Inside Ardena Somerset: US-Based ASD and Oral Solid Manufacturing

Why a US Site Matters

For biotech companies based in North America, time zone alignment and proximity are not trivial. A development partner eight hours ahead means decisions made in the afternoon do not get actioned until the next day. Equipment access, sample shipping, and site visits all become harder when the facility is on another continent.

Ardena’s Somerset, New Jersey site gives North American sponsors a US-based manufacturing partner with direct access to the oral solid and bioavailability enhancement capabilities the Ardena network is known for. The same scientific standards, the same quality systems, the same integrated project management, but in the same time zone.

What the Site Does

Spray Drying for Amorphous Solid Dispersions

Somerset’s core strength is spray-dried amorphous solid dispersion (ASD) manufacture. The site operates laboratory and GMP-scale spray drying equipment with closed-loop solvent recovery and secondary drying capability. The formulation team has developed ASDs across a wide range of BCS Class II molecules and polymer systems, including HPMC-AS, PVPVA, and PVP-K grades.

Development programmes at Somerset start with feasibility: does this molecule respond to ASD? If yes, which polymer gives the best balance of dissolution performance, physical stability, and processability? From there, the team scales through development batches to GMP clinical manufacture within the same facility, with no formal tech transfer between scales.

Hot Melt Extrusion

HME capability at Somerset serves molecules where spray drying is less suitable, typically thermally stable APIs where a solvent-free process is preferred or where the downstream processing of a spray-dried powder presents challenges. The site’s HME expertise covers twin-screw extrusion, extrudate milling, and downstream tabletting or capsule filling of the milled intermediate.

Downstream Oral Solid Manufacturing

Somerset handles the full downstream processing chain for ASD-based products: granulation where required, blending, tabletting, and capsule filling. Analytical capabilities support content uniformity, dissolution testing, and stability studies from development through to GMP release.

Who Somerset Is Built For

Programme Type	Why Somerset Is a Good Fit
BCS Class II molecules needing ASD strategy	Spray drying and HME under one roof; formulation screening to GMP clinical batch at a single site
North American sponsors wanting US-based manufacturing	Same time zone; direct site access; FDA cGMP operations; no import/export logistics for US clinical supply
Programmes requiring dual US/EU clinical supply	Somerset provides FDA cGMP US supply; Ghent or Pamplona provides EU GMP supply under coordinated Ardena project management
Early-phase ASD feasibility with tight timelines	Rapid screening capability; formulation team responds quickly; no transatlantic coordination overhead
IND-stage oral solid programmes	Experience preparing CMC sections for IND submissions; regulatory team aligned with FDA expectations

The Connection to the European Network

Somerset is not an isolated US operation. It is a node in the Ardena network, with direct scientific and project management connections to Ghent, Oss, Assen, and Pamplona. For programmes where solid state work needs to happen in Ghent before formulation development begins in Somerset, the handoff is internal. For programmes requiring EU GMP supply for European trials alongside US supply from Somerset, a single project manager coordinates both.

That integration removes the coordination overhead that sponsors would otherwise manage themselves when using a US development house alongside a separate European manufacturer.

High Potency API Manufacturing: Safety by Design

What Makes a Compound High Potency?

The term high potency active pharmaceutical ingredient (HPAPI) refers to any compound with significant biological activity at very low doses, typically below 1 milligram per day in humans, or with occupational exposure limits in the microgram per cubic metre range. The category includes cytotoxic oncology agents, hormonal compounds, certain immunosuppressants, and novel targeted therapies with high receptor affinity.

The manufacturing challenge with HPAPIs is not the chemistry itself, which may be no more complex than for conventional APIs, but the containment required to protect operators and the environment from exposure to a compound that causes harm at extremely low concentrations. The engineering controls, facility design, and operational procedures needed to handle HPAPIs safely are substantially different from those applicable to conventional pharmaceutical manufacturing, and they must be in place before any GMP manufacturing campaign begins.

The Occupational Exposure Banding Framework

Occupational exposure banding (OEB) is the standard industry framework for classifying the hazard of a pharmaceutical compound based on its potency, toxicology profile, and pharmacological activity, and for defining the corresponding engineering controls required for safe handling. The ISPE guide to risk-based manufacture of pharmaceutical products and guidance from the American Industrial Hygiene Association (AIHA) provide frameworks for OEB classification. Most CDMOs use a five-band or six-band system, with Band 4 and Band 5 requiring the most stringent containment.

OEB Band	OEL Range (8-hour TWA)	Typical Compound Types	Required Containment Level
OEB 1	Greater than 1 mg/m3	Conventional APIs with low hazard	Standard pharmaceutical engineering controls
OEB 2	0.1 to 1 mg/m3	APIs with moderate potency	Local exhaust ventilation; PPE
OEB 3	0.01 to 0.1 mg/m3	Potent APIs; some hormones	Closed or semi-closed processing; enhanced PPE
OEB 4	0.001 to 0.01 mg/m3 (1 to 10 micrograms/m3)	Cytotoxics; HPAPIs; most ADC payloads	Containment isolators or RABS; dedicated facilities or rigorous decontamination
OEB 5	Below 0.001 mg/m3 (below 1 microgram/m3)	Genotoxic compounds; highly potent cytotoxics; TCDD-like compounds	Dedicated facility; full containment isolators; continuous air monitoring; stringent decontamination validation

OEL ranges above represent typical band definitions and may vary between organisations and classification systems. Compound-specific OELs should always be established by qualified industrial hygienists.

Engineering Controls: The Hierarchy of Protection

The occupational health principle of the hierarchy of controls applies directly to HPAPI manufacturing. Elimination and substitution are rarely options for an API that is the entire point of the product. Substitution with a less hazardous alternative may be possible at the discovery stage but not at the development stage. Engineering controls, specifically containment technology, are therefore the primary means of protecting operators.

Closed Handling Systems

At OEB 3 and lower OEB 4, closed handling systems including contained transfer systems and split butterfly valves allow material to be transferred between vessels and equipment without operator exposure. These systems are widely used in pharmaceutical manufacturing for potent materials and do not require a dedicated facility.

Containment Isolators

For OEB 4 and OEB 5 compounds, manufacturing operations must be conducted inside containment isolators: sealed enclosures with integrated glove ports that allow operators to manipulate materials inside without direct contact. Isolators maintain negative pressure relative to the surrounding environment, ensuring that any leak is inward rather than outward. Decontamination of the isolator between campaigns is typically achieved using hydrogen peroxide vapour or other validated decontamination agents.

Facility Design

At the highest potency levels, dedicated facilities with separate HVAC systems, airlocks, and personnel decontamination facilities are required. The facility must be validated to demonstrate that decontamination procedures achieve adequate removal of the compound from surfaces and that the HVAC system prevents cross-contamination with less potent products. Continuous environmental monitoring for HPAPI compounds in work area air is standard practice at OEB 4 and 5.

Process Design for HPAPI Manufacturing

Containment is not only about the physical infrastructure. The manufacturing process itself must be designed to minimise the number of open handling steps, reduce the generation of dust and aerosols, and simplify the decontamination requirements. Process design considerations for HPAPI manufacturing include using wet granulation rather than dry granulation where the API is amenable, minimising the number of charging and discharging operations, and using in-line or at-line analytical methods that do not require sample removal from the contained environment.

Ardena’s HPAPI Manufacturing Capability at Pamplona

Ardena’s Pamplona (Idifarma) facility in Spain provides OEB 3, 4, and 5 manufacturing capability for high potency API and drug product development and GMP manufacturing. The site is equipped with containment isolators for handling at the highest potency levels, dedicated HPAPI suites with appropriate HVAC segregation, and validated decontamination procedures.

Pamplona’s HPAPI capability supports both drug substance synthesis and drug product manufacturing for oral solid and injectable dosage forms, covering the full manufacturing chain for oncology compounds, ADC payloads, and other high-potency molecules from pre-GMP development through to clinical batch supply.

Hot Melt Extrusion vs. Spray Drying: Choosing Your ASD Technology

Two Routes to the Same Goal

When a BCS Class II molecule needs bioavailability enhancement and simpler approaches such as particle size reduction or salt selection have not provided a sufficient solution, amorphous solid dispersions are often the next logical step. The two dominant manufacturing technologies for pharmaceutical ASDs are hot melt extrusion (HME) and spray drying, and both have a strong track record of producing commercially approved products.

The choice between them is not arbitrary. Each technology imposes different constraints on the API, the polymer, and the downstream processing, and the right choice depends on the physicochemical properties of the molecule, the intended commercial manufacturing scale, and the regulatory pathway. Making this decision early, at the pre-formulation or early formulation stage, avoids late-stage redevelopment.

How Each Technology Works

Hot Melt Extrusion (HME)

In HME, the API and polymer are blended as dry powders and fed into a heated extruder barrel where the polymer melts and the API dissolves or disperses within the polymer melt. The twin-screw extruder applies both heat and mechanical shear to the material, facilitating mixing and dispersion at the molecular level. The molten extrudate is cooled and then processed into the desired particle size, typically by milling or pelletisation, before being formulated into tablets or capsules.

HME is a continuous, solvent-free process, which is an advantage both for manufacturing efficiency and for regulatory simplicity around residual solvent control. The absence of organic solvents also makes it more straightforward to implement in a GMP environment from an occupational health and environmental perspective.

Spray Drying

In spray drying, the API and polymer are co-dissolved in a common organic solvent (or solvent mixture) and the solution is atomised into a heated drying chamber where the solvent evaporates rapidly, leaving behind solid particles of the API-polymer dispersion. The particle size of the spray-dried intermediate is controlled by atomisation conditions including feed rate, atomiser type, and inlet temperature.

Spray drying is a batch or semi-continuous process that requires solvent handling, solvent recovery, and residual solvent control to below ICH Q3C limits. However, it is applicable to a wider range of APIs and polymers than HME because it does not require the API to be thermally stable at the processing temperatures needed to melt the polymer.

Head-to-Head Comparison

Selection Factor	Hot Melt Extrusion	Spray Drying
API thermal stability	Required: API must be stable at polymer melt temperature (typically 100-200 degrees C)	Not required: API only exposed to moderate temperatures during solvent evaporation
API solubility in polymer	Good molecular mixing requires API to dissolve in or be miscible with polymer melt	API and polymer must share a common solvent; molecular solubility in polymer less critical
Polymer selection	Must melt at processable temperatures; HPMC-AS and PVPVA are less suited to HME due to high Tg	Broad polymer compatibility; HPMC-AS, PVPVA, PVP-K, Eudragit all spray-dried commercially
Solvent use	Solvent-free; no residual solvent concern	Requires solvent handling, recovery, and ICH Q3C compliance
Drug loading	Typically limited by melt viscosity and extruder torque; often 10-40% w/w	Broader range achievable; depends on API/polymer solubility in solvent
Scale-up	Highly scalable; continuous processing; well-established at commercial scale	Well-established at commercial scale; batch or semi-continuous
Regulatory precedent	Extensive; Kaletra (lopinavir/ritonavir), Noxafil (posaconazole)	Extensive; Zelboraf (vemurafenib), Incivek (telaprevir)
Best suited for	Thermally stable APIs; solvent-free preference; continuous manufacturing	Thermally labile APIs; broad polymer choice; rapid early-stage screening

Making the Decision in Practice

For molecules with good thermal stability and compatibility with HME-processable polymers, HME offers a cleaner manufacturing process with no solvent handling overhead and strong scale-up credentials. For thermally labile molecules, or programmes where early-stage feasibility screening across a broad polymer matrix is the priority, spray drying is typically the first technology evaluated.

In practice, the two technologies are often evaluated in parallel at the screening stage, and the selection is made based on the comparative performance data, manufacturability assessment, and the commercial manufacturing infrastructure available at the intended development and manufacturing partner.

Ardena’s ASD Manufacturing Capabilities

Ardena operates spray drying and hot melt extrusion capabilities at its Somerset, New Jersey facility and at Pamplona (Idifarma) in Spain. Both sites can support ASD development from early screening through to GMP clinical batch manufacture. The formulation development teams at these sites have extensive experience with the full range of ASD-relevant polymers and can advise on technology selection based on the API’s physicochemical profile and the programme’s development goals.

CMC Regulatory Dossiers for Nanomedicines: Module 3 Deep Dive

Why Standard Module 3 Templates Fall Short for Nanomedicines

The Common Technical Document (CTD) Module 3 template was designed for conventional small molecule and biological drug products. For nanomedicine products, including lipid nanoparticles, polymeric nanoparticles, and metal oxide nanoparticle systems, the template provides a useful framework but cannot accommodate the full complexity of the characterisation data required without substantial adaptation.

The fundamental difference is that for a conventional drug product, the drug substance and the drug product are distinct entities that are characterised and controlled separately. For an LNP encapsulating mRNA, the physical properties of the particle, its size, charge, composition, and payload integrity, are not properties of the drug substance alone or the drug product alone: they emerge from the combination and the manufacturing process that brings them together. Regulators expect the CMC package to reflect this complexity.

The Key Additions to Module 3 for Nanomedicine Products

Module 3 Section	Standard Content	Nanomedicine-Specific Additions
3.2.P.1 Description and Composition	Formulation composition and dosage form description	Nanoparticle system description; lipid or polymer composition; molar ratios; N:P ratio for nucleic acid products
3.2.P.2 Pharmaceutical Development	Formulation rationale; manufacturing process development	CQA identification and justification; design space for particle size and encapsulation; lipid selection rationale; process analytical technology (PAT) tools used
3.2.P.3 Manufacture	Manufacturing process description and controls	Microfluidics or extrusion process parameters; critical process parameters with ranges; in-process controls including real-time particle size monitoring
3.2.P.4 Control of Excipients	Excipient specification and source	Novel lipid excipient characterisation; supplier qualification; impurity profile for ionisable lipids
3.2.P.5 Control of Drug Product	Release specification and methods	Nanoparticle-specific release tests: particle size, PDI, EE%, zeta potential, in vitro release; analytical method description and justification
3.2.P.6 Reference Standards	Reference standard description	Reference nanoparticle batch for comparability; reference payload (mRNA or small molecule)
3.2.P.8 Stability	Stability protocol and data	Nanoparticle-specific stability attributes; physical stability monitoring by XRPD or DLS; storage condition justification for frozen products

Physicochemical Characterisation: Going Beyond the Four CQAs

While particle size, PDI, encapsulation efficiency, and zeta potential are the core release CQAs for most nanomedicine products, regulators expect a more comprehensive characterisation package in the pharmaceutical development section that demonstrates a thorough understanding of the product’s critical quality attributes and their relationship to clinical performance.

Morphology

Transmission electron microscopy (TEM) or cryo-TEM provides direct visual confirmation of nanoparticle morphology, including particle shape, internal structure (for core-shell systems), and the absence of gross aggregation. Cryo-TEM is particularly valuable for LNPs because it images the particles in their native hydrated state, avoiding the artefacts introduced by conventional TEM sample preparation.

Lipid Composition and Purity

The identity and purity of each lipid component must be confirmed in every batch. HPLC-UV or HPLC-ELSD methods are used to quantify the intact lipid species, and LC-MS is used to identify and quantify lipid degradation products, including hydrolysis products and oxidation products, particularly for unsaturated lipids. The FDA’s guidance on drug product impurities applies to lipid degradation products, and the acceptance criteria for these impurities must be justified based on safety data.

mRNA Integrity and Potency (for mRNA Products)

For mRNA LNP products, the integrity of the mRNA payload must be confirmed in the final drug product. Agarose gel electrophoresis or capillary gel electrophoresis is used to assess mRNA integrity, detecting degradation as a shift in the size distribution or the appearance of shorter fragments. An in vitro translation assay using cell-free or cell-based expression systems is used to confirm that the mRNA in the final product retains its biological potency.

Comparability and Manufacturing Changes

For nanomedicine products, manufacturing changes that would be considered minor for a conventional solid dosage form can have significant effects on product quality. A change in the microfluidics chip geometry, the process temperature, or the lipid supplier can shift the particle size distribution, alter the encapsulation efficiency, or change the in vivo behaviour of the product. Regulators expect a rigorous comparability exercise for any manufacturing change that could affect the physicochemical properties of the nanoparticle, and the comparability data must include the full suite of CQAs and, where appropriate, in vitro biological activity data.

How Ardena Builds Nanomedicine CMC Packages

Ardena’s regulatory team works alongside the formulation scientists and analytical chemists at Oss to build Module 3 CMC packages for nanomedicine IND and IMPD filings. The team has experience adapting the CTD format for LNP, polymeric nanoparticle, and metal oxide nanoparticle products, and can advise on the current FDA and EMA expectations for characterisation data and analytical method validation for nanoparticle-specific methods.

Nanosuspensions: When Nano Is the Simplest Solution

Not Every Solubility Problem Needs a Complex Solution

When a development team encounters a BCS Class II molecule with poor aqueous solubility, the instinct is often to reach for the most technically sophisticated tool available: an amorphous solid dispersion by hot melt extrusion or spray drying, or a lipid-based formulation system. These technologies are powerful, but they are also complex, expensive, and demanding in terms of development time and manufacturing infrastructure.

A nanosuspension, a stabilised colloidal dispersion of drug nanocrystals in an aqueous medium, offers a different proposition. It keeps the API in its crystalline form, which means no stability concerns around amorphous recrystallisation. It improves dissolution rate through surface area enhancement, without requiring a polymer matrix, a solvent system, or a high-shear processing step. For the right molecule, it is genuinely the simplest route to adequate oral bioavailability.

The Science of Dissolution Enhancement by Nanosuspension

The Noyes-Whitney equation tells us that dissolution rate is proportional to surface area. Reducing a drug particle from a D90 of 100 micrometres to a D90 of 200 nanometres increases the specific surface area by approximately a factor of 500, producing a proportional increase in intrinsic dissolution rate. For BCS Class II molecules where dissolution is the rate-limiting step in absorption, this translates into a meaningful increase in Cmax and AUC relative to a conventional micronised formulation.

Nanosuspensions can also achieve a modest increase in apparent solubility relative to the bulk crystalline form through the Ostwald-Freundlich effect, which predicts an increase in solubility for very small particles due to the increased surface free energy. This effect is generally modest for particles above 100 nanometres, and the primary driver of bioavailability improvement in pharmaceutical nanosuspensions is dissolution rate enhancement rather than solubility enhancement.

Nanosuspension vs. ASD: Choosing the Right Approach

Factor	Nanosuspension	Amorphous Solid Dispersion (ASD)
API solid state	Crystalline throughout	Amorphous; stability risk
Solubility enhancement mechanism	Dissolution rate (surface area); modest Ostwald-Freundlich effect	Supersaturation; higher apparent solubility; requires precipitation inhibitor
Magnitude of enhancement	Moderate; typically 2-10 fold improvement in AUC vs micronised	Can be substantial; 10-100 fold for low-solubility molecules
Development complexity	Lower; no polymer excipient system required	Higher; polymer selection, drug-polymer miscibility, downstream processing
Manufacturing equipment	Wet milling or media milling; established technology	Spray drying or HME; specialist equipment
Physical stability	High; crystalline API is thermodynamically stable	Lower; amorphous conversion risk requires careful packaging and storage
Best suited for	Moderate solubility gap; stable crystalline API; simple downstream processing	Severe solubility gap; molecule responds well to supersaturation strategy

Critical Formulation Considerations for Nanosuspensions

Stabiliser Selection

Nanosuspensions are thermodynamically unstable systems that will aggregate if not adequately stabilised. Stabilisers adsorb to the particle surface and prevent particle-particle contact by steric or electrostatic mechanisms. Common pharmaceutical stabilisers for nanosuspensions include HPMC, HPMC-AS, poloxamer 188, poloxamer 407, and polysorbate 80. The selection of stabiliser type and concentration is empirical and depends on the surface chemistry of the specific API.

Milling Parameters

For wet-milled nanosuspensions, the target particle size and size distribution are controlled by milling time, bead size and loading, mill speed, and temperature. Milling at elevated temperature can lead to polymorphic conversion in sensitive molecules, making temperature monitoring and control during milling important. The milling process must be developed and characterised to define the process parameters that reproducibly achieve the target particle size specification.

Downstream Conversion to Solid Dosage Form

Most clinical and commercial nanosuspension products are converted from the liquid nanosuspension intermediate into a solid dosage form, typically a tablet or capsule, by spray drying, fluid bed granulation, or lyophilisation. The conversion process must maintain the nanoparticle size distribution: if particles aggregate during drying or granulation, the bioavailability advantage is lost. Redispersibility testing of the final solid dosage form in simulated gastrointestinal fluids is an important part of the characterisation package.

Ardena’s Nanosuspension Development Capabilities

Ardena’s nanomedicine team at Oss has wet milling and media milling capability for nanosuspension development at both screening and scale-up. Particle size characterisation by DLS and laser diffraction, stabiliser screening, and downstream conversion studies are conducted as part of integrated nanosuspension development programmes.

Polymeric Nanoparticles for Sustained Drug Release

The Case for Sustained Release at the Nanoscale

Many therapeutic molecules have pharmacokinetic profiles that are poorly suited to their intended use. A drug that clears from circulation within a few hours may need to be dosed multiple times daily to maintain therapeutic concentrations, creating peaks and troughs in exposure that lead to toxicity at Cmax and loss of efficacy at Ctrough. For chronic conditions requiring long-term treatment, the dosing burden affects patient adherence and quality of life.

Polymeric nanoparticles address this by encapsulating the drug within a biodegradable polymer matrix that releases its payload gradually as the polymer degrades or the drug diffuses through the matrix wall. Release profiles ranging from days to weeks can be engineered by selecting the polymer composition, molecular weight, and drug loading, providing a level of pharmacokinetic control that is difficult to achieve with conventional extended-release oral formulations for many drug classes.

PLGA: The Workhorse Polymer for Sustained Release Nanoparticles

Poly(lactic-co-glycolic acid) (PLGA) is the most widely used biodegradable polymer in pharmaceutical nanoparticle formulations. It is approved for use in parenteral drug products, has a well-characterised safety profile, and degrades in vivo by hydrolysis to lactic acid and glycolic acid, both naturally occurring metabolic products. The FDA’s guidance on biodegradable drug products provides the framework for the characterisation and safety data required for PLGA-based products.

The degradation rate of PLGA depends on the ratio of lactic to glycolic acid monomer units, the molecular weight of the polymer, and the end-group chemistry. High glycolic acid content and low molecular weight produce faster degradation; high lactic acid content and high molecular weight produce slower degradation. This tunability allows the release profile to be tailored across a wide range by selecting the appropriate PLGA grade.

Release Mechanisms in Polymeric Nanoparticles

Release Mechanism	How It Works	Polymer System	Typical Release Profile
Surface erosion	Polymer degrades from outside in; drug released as surface layers are removed	Polyanhydrides; surface-eroding PLGA formulations	Near zero-order release; sustained over weeks
Bulk erosion	Polymer absorbs water and degrades throughout the matrix simultaneously	PLGA (predominant mechanism); PLA	Biphasic: initial burst followed by sustained release as matrix erodes
Diffusion	Drug diffuses through the intact polymer matrix to the surface	Dense polymer cores; crosslinked hydrogels	Rate depends on drug size, matrix porosity, and diffusion path length
Swelling and diffusion	Polymer swells on water uptake; drug diffuses through swollen matrix	HPMC; polyacrylates; hydrophilic matrices	Relatively constant release rate; suitable for hydrophilic drugs

Formulation Variables That Control Release Rate

Polymer Molecular Weight and Composition

As discussed above, PLGA molecular weight and L:G ratio are the primary handles for controlling the bulk degradation rate and thus the drug release profile. A PLGA 50:50 (equal lactic and glycolic acid) degrades significantly faster than a PLGA 75:25 or PLGA 85:15. Within a given composition, higher molecular weight polymers degrade more slowly. Matching polymer selection to the target release duration is the starting point for any polymeric nanoparticle formulation design.

Drug Loading and Drug-Polymer Interactions

Higher drug loading can increase the initial burst release if the drug is present at the particle surface, and can affect matrix integrity and degradation rate if the drug-polymer interaction alters the physical properties of the matrix. Drug loading is typically optimised alongside release profile in early development to identify the combination that achieves the target exposure profile without compromising physical stability or manufacturability.

Particle Size

Smaller particles have a larger surface area to volume ratio, which generally increases the rate of surface-mediated drug release and can enhance the initial burst. For sustained release applications where a prolonged low-level release is desired, larger particles or core-shell architectures may better suppress the burst release component.

Analytical Characterisation of Polymeric Sustained Release Nanoparticles

In addition to the standard nanoparticle CQAs of particle size, PDI, and zeta potential, sustained release polymeric nanoparticle products require drug content assay, in vitro release testing, and polymer characterisation including molecular weight distribution by gel permeation chromatography (GPC). In vitro release testing for parenteral sustained release nanoparticles is technically challenging because standard dissolution apparatus is not designed for nanoparticle systems; sample and separate methods, membrane diffusion cells, and dialysis-based approaches are all used, and the choice of method affects the release profile observed.

Ardena’s Polymeric Nanoparticle Capabilities at Oss

Ardena’s nanomedicine team at Oss has formulation expertise in polymeric nanoparticle systems including PLGA, PLA, and other biodegradable polymer platforms. Development programmes include polymer selection, drug loading optimisation, in vitro release method development, and physicochemical characterisation using DLS, NTA, and GPC.

Regulatory Strategy for LNP-Based Therapies: A 2026 Update

A Rapidly Maturing Regulatory Framework

The approval of the first mRNA COVID-19 vaccines in late 2020 was a watershed moment for LNP-based medicines and for the regulatory agencies that oversee them. Within the space of two years, both the FDA and EMA moved from limited experience with LNP products to reviewing and approving the most widely administered pharmaceutical products in history. The data generated during that period, on LNP characterisation, stability, immunogenicity, and manufacturing, has fundamentally shaped the expectations that regulators now bring to new LNP development programmes.

The regulatory frameworks for nanomedicines continue to evolve, and developers entering the field in 2026 face a more defined but also more scrutinised path than those who filed the first LNP programmes a decade ago. This article outlines the current regulatory expectations for LNP-based therapeutics at both the FDA and EMA.

Key Regulatory Guidance Documents for LNP Developers

Document	Agency	Relevance to LNP Programmes
Guidance for Industry: Drug Products, Including Biological Products, that Contain Nanomaterials (2022)	FDA	Defines nanomaterial scope; addresses CMC characterisation expectations including particle size, surface properties, and stability
Reflection Paper on Nanotechnology-Based Medicinal Products for Human Use (EMA/CHMP/79769/2006 and updates)	EMA	Foundational guidance on physicochemical characterisation and non-clinical testing expectations for nanomedicine products
ICH Q8(R2) Pharmaceutical Development	ICH	Quality by Design framework applicable to LNP development; design space and control strategy concepts
ICH Q2(R2) Analytical Validation	ICH	Validation requirements for LNP-specific analytical methods including encapsulation assays and particle characterisation
FDA mRNA Product-Specific Guidance	FDA	Product-specific guidance documents for mRNA vaccines and therapeutics addressing CMC and non-clinical requirements
EMA Guideline on Excipients in the Dossier for Application for Marketing Authorisation	EMA	Relevant to novel lipid excipients used in LNP formulations that are not covered by existing compendial monographs

CMC Expectations for an LNP IND or IMPD Filing

Drug Substance: The Nucleic Acid Payload

For mRNA-based LNP products, the mRNA is the drug substance, and the LNP is the drug product formulation system. The mRNA drug substance section of Module 3 must address the mRNA sequence and structure including the 5-prime cap, UTR design, and codon optimisation strategy, the manufacturing process for in vitro transcription, the impurity profile including residual template DNA, truncated transcripts, and dsRNA, and the analytical methods used to characterise sequence integrity, purity, and potency. FDA’s guidance on mRNA drug substance CMC provides the current framework for these requirements.

Drug Product: The LNP Formulation

The drug product section must describe the LNP composition including the identity and grade of each lipid component, the drug-to-lipid ratio, and the buffer system. Novel ionisable lipids that are not described in the current literature or approved products require a more detailed justification of their physical and safety properties. The manufacturing process description must cover the microfluidics or extrusion process, the critical process parameters and their ranges, and the in-process controls applied at each step.

Characterisation: The Critical Quality Attributes

Regulators expect a comprehensive physicochemical characterisation package covering at minimum particle size and PDI, encapsulation efficiency, zeta potential, lipid composition (identity and purity of each lipid component), mRNA integrity, and potency by in vitro translation assay. The method used to measure each CQA must be described, and where the method is not a compendial or established published method, abbreviated validation data supporting fitness for purpose is expected at the IND or IMPD stage.

Stability: Supporting the Clinical Trial Duration

The stability data submitted with an IND or IMPD must cover the duration of the intended clinical trial, including a margin for shipping and site storage. For LNP products stored at minus 20 or minus 80 degrees Celsius, the stability programme must include data at the intended long-term storage condition and, ideally, at an intermediate temperature to demonstrate the impact of inadvertent excursions. Accelerated stability data at minus 20 degrees Celsius for products stored at minus 80 degrees Celsius is increasingly expected by regulators as an indicator of the stability margin.

The Novel Excipient Question

Many of the ionisable lipids used in current LNP programmes are proprietary compounds not described in pharmacopoeial monographs or in the composition of previously approved products. Regulators classify these as novel excipients and require a more comprehensive safety and characterisation package than would be required for an established excipient. For Phase I filings, the FDA and EMA have accepted abbreviated novel excipient packages that focus on physicochemical characterisation and the non-clinical toxicology data generated in the IND-enabling studies. The full novel excipient justification is required at the NDA or MAA stage.

How Ardena Supports LNP Regulatory Filings

Ardena’s regulatory team works alongside its nanomedicine formulation scientists at Oss to build CMC packages for LNP-based IND and IMPD filings. The team has experience preparing Module 3 sections for both mRNA LNP and small molecule LNP products, and can advise on the current FDA and EMA expectations for characterisation data, novel excipient justification, and stability programme design.

Gold and Iron Oxide Nanoparticles in Diagnostic Imaging

Inorganic Nanoparticles in Pharmaceutical Development

The pharmaceutical nanoparticle landscape extends well beyond lipid and polymer systems. Metal and metal oxide nanoparticles, particularly gold nanoparticles and iron oxide nanoparticles, have physical properties that make them uniquely useful in diagnostic imaging, thermal therapy, and the emerging field of theranostics, where a single agent combines diagnostic and therapeutic functions.

Interest in these materials has grown steadily alongside advances in nanomedicine formulation science, and several iron oxide nanoparticle products are already approved for clinical use as MRI contrast agents. The broader field of metal nanoparticle applications in pharmaceuticals is advancing through clinical development, with programmes in cancer imaging, hyperthermia therapy, and targeted drug delivery among those in active investigation.

Iron Oxide Nanoparticles: MRI Contrast and Beyond

How Iron Oxide Nanoparticles Enhance MRI Contrast

Superparamagnetic iron oxide nanoparticles (SPIONs) enhance the contrast of magnetic resonance imaging by shortening the T2 and T2* relaxation times of water protons in tissues where the particles accumulate. This produces a signal reduction (darkening) in T2-weighted images, allowing tissues with SPION accumulation to be distinguished from surrounding tissue. The degree of contrast enhancement depends on the size, surface coating, and magnetic properties of the particles.

Approved SPION-based MRI contrast agents including ferumoxytol are used clinically for imaging of the lymphatic system, the liver, and the vasculature. The EMA’s reflection paper on non-clinical studies for generic nanoparticle medicinal products provides guidance relevant to the development of SPION-based imaging agents and new nanoparticle therapeutics.

Emerging Applications: Hyperthermia and Drug Delivery

Beyond MRI contrast, iron oxide nanoparticles can generate heat when exposed to an alternating magnetic field, a phenomenon known as magnetic hyperthermia. Localised heat generation in tumour tissue can directly kill cancer cells or sensitise them to concurrent chemotherapy or radiotherapy. Magnetic hyperthermia using iron oxide nanoparticles has been investigated in clinical trials for glioblastoma and prostate cancer.

Surface-functionalised iron oxide nanoparticles can also act as drug carriers, with the magnetic core providing imaging capability and the surface providing a platform for drug loading and targeting ligand attachment. This combination of imaging and therapeutic function in a single particle is the theranostic concept at its most direct.

Gold Nanoparticles: Optical Properties and Biomedical Applications

Surface Plasmon Resonance

Gold nanoparticles exhibit a phenomenon known as surface plasmon resonance: the conduction electrons on the gold surface oscillate in resonance with incident light at specific wavelengths, producing intense absorption and scattering at those wavelengths. The resonance wavelength depends on the size and shape of the particle and can be tuned from the visible to the near-infrared range by controlling particle geometry during synthesis.

This optical tunability makes gold nanoparticles attractive for photothermal therapy, where near-infrared light penetrates tissue and is absorbed by gold nanoparticles localised in the tumour, generating heat that destroys tumour cells. Near-infrared light causes minimal damage to surrounding tissue, making this a highly targeted thermal ablation approach.

Surface Functionalisation for Drug Delivery

The surface of gold nanoparticles can be functionalised with a wide range of chemical groups, including thiol-linked molecules, antibodies, oligonucleotides, and polymer coatings. This versatility makes gold nanoparticles a flexible platform for targeted drug delivery, where the gold core provides photothermal or imaging capability and the surface carries therapeutic cargo and targeting ligands.

Characterisation Requirements for Inorganic Nanoparticles

Property	Measurement Technique	Regulatory Relevance
Core size and size distribution	Transmission electron microscopy (TEM); X-ray diffraction	Core size affects magnetic and optical properties; must be defined and controlled
Hydrodynamic diameter and PDI	Dynamic light scattering (DLS)	Reflects particle size in biological media including protein corona formation
Surface chemistry and coating	X-ray photoelectron spectroscopy (XPS); FTIR; NMR	Surface coating determines colloidal stability, protein adsorption, and biological fate
Zeta potential	Electrophoretic light scattering	Colloidal stability indicator; relevant to aggregation and non-specific interactions
Metal content and purity	ICP-MS or ICP-OES	Precise metal quantification for dose control; impurity profiling required for regulatory filing
Endotoxin and sterility	LAL assay; sterility testing	Critical for injectable products; inorganic nanoparticles can interfere with standard LAL assays

Characterisation requirements for metal nanoparticle pharmaceuticals are evolving. Regulatory expectations should be confirmed with the relevant agency for each specific application and development stage.

Ardena’s Metal and Metal Oxide Nanoparticle Platform

Ardena’s nanomedicine team at Oss has experience with metal and metal oxide nanoparticle systems, including formulation development, physicochemical characterisation, and GMP manufacturing support for inorganic nanoparticle products. The analytical capabilities at Oss include DLS, zeta potential measurement, and the infrastructure for handling metal-containing pharmaceutical materials under GMP conditions.

From mRNA to Protein: Understanding LNP Delivery Efficiency

The Problem That Most mRNA Gets Wrong

The appeal of mRNA therapeutics is straightforward: deliver the genetic instructions for a beneficial protein directly into cells, let the cell’s own machinery produce the protein, and achieve a therapeutic effect without permanently altering the genome. The challenge is equally clear: mRNA is a large, negatively charged, inherently unstable molecule that cannot cross cell membranes unaided, is degraded rapidly by extracellular RNases, and triggers innate immune responses that can abort expression before it begins.

Lipid nanoparticles have become the delivery system of choice for mRNA therapeutics precisely because they address these barriers. But not all LNPs deliver mRNA with equal efficiency. Understanding the intracellular journey from LNP uptake to protein expression, and the points at which that journey can fail, is essential for designing formulations that maximise therapeutic protein output.

The Intracellular Delivery Pathway

Step 1 — Cellular Uptake

LNPs enter cells primarily through endocytosis, a process in which the cell membrane engulfs the particle and internalises it within an endosome. The efficiency of uptake depends on the particle size, surface properties, and the extent to which the LNP has adsorbed apolipoprotein E (ApoE) from plasma, which facilitates receptor-mediated uptake in hepatocytes via the LDL receptor pathway. For non-hepatic targets, surface modification with targeting ligands can enhance uptake in specific cell types.

Step 2 — Endosomal Escape

This is the critical bottleneck in LNP-mediated mRNA delivery. After cellular uptake, the LNP is contained within an endosome, and the endosome matures progressively from early endosome through late endosome to lysosome, with decreasing pH at each stage. If the mRNA does not escape the endosome before lysosomal degradation occurs, it is destroyed and no protein expression results.

Ionisable lipids are the key functional component that drives endosomal escape. At physiological pH they are largely neutral, which reduces non-specific toxicity in circulation. At the acidic pH of the late endosome, they become protonated and positively charged, disrupting the endosomal membrane and enabling mRNA release into the cytoplasm. The efficiency of this process, often described as endosomal escape efficiency, is typically low: published estimates suggest that fewer than 2% of endocytosed LNPs successfully deliver their mRNA cargo to the cytoplasm.

Step 3 — Translation

Once mRNA reaches the cytoplasm, it is translated by ribosomes into the encoded protein. The efficiency of translation depends on the quality and integrity of the mRNA, including its 5-prime cap structure, the design of the untranslated regions (UTRs), and the codon optimisation of the coding sequence. mRNA degradation by cytoplasmic RNases competes with translation throughout the expression period.

Formulation Variables That Drive Delivery Efficiency

Formulation Variable	Effect on Delivery	Optimisation Approach
Ionisable lipid selection	Primary driver of endosomal escape efficiency; pKa affects pH-response profile	Screen ionisable lipids across a range of apparent pKa values; target pKa 6.2-6.8 for hepatic delivery
Lipid molar ratios	Balance between encapsulation, stability, and endosomal escape activity	Design of experiments to map formulation space; optimise N:P ratio for each mRNA
PEG-lipid content and PEG chain length	Modulates particle size, colloidal stability, and cellular uptake	Higher PEG content reduces uptake; shed-able PEG chains can improve delivery
mRNA : lipid ratio (N:P ratio)	Determines encapsulation efficiency and particle charge	Typically optimised to achieve greater than 85% encapsulation with near-neutral zeta potential
Microfluidics mixing parameters	Affects particle size and homogeneity during formulation	Optimise flow rate ratio and total flow rate for target particle size

Measuring Delivery Efficiency In Vitro

The standard cell-based assay for measuring LNP transfection efficiency uses a reporter system, typically luciferase or green fluorescent protein (GFP), where the mRNA encodes a readily detectable protein. Cells are incubated with the LNP at defined concentrations for a defined period, and protein expression is measured by luminescence or fluorescence. Comparing luminescence or fluorescence across formulations with identical mRNA doses gives a direct readout of relative delivery efficiency.

In vitro delivery efficiency is a useful screening tool for ranking formulations, but it does not always predict in vivo performance. Cell lines used for screening may have different uptake and endosomal biology to the target cell type in vivo, and the absence of serum proteins including ApoE in some in vitro assays can significantly underestimate hepatic delivery efficiency.

Ardena’s mRNA LNP Formulation Expertise at Oss

Ardena’s formulation scientists in Oss have expertise in ionisable lipid-based LNP formulation for mRNA and nucleic acid payloads. The site operates microfluidics and nanoparticle extrusion platforms for LNP manufacture at both screening and GMP scale, with integrated analytical capability for particle size, PDI, encapsulation efficiency, and zeta potential measurement.

Formulation development programmes at Oss are structured to move efficiently from initial lipid screening through to a robust formulation with defined critical quality attributes, supported by in vitro characterisation and stability data suitable for an IND or IMPD filing.

Lipid Nanoparticle Characterisation: The 4 CQAs You Cannot Skip

Why CQAs Matter More for LNPs Than for Conventional Drug Products

For a conventional small molecule tablet, the critical quality attributes that determine in vivo performance, dissolution rate, disintegration time, content uniformity, are relatively straightforward to measure and control. For a lipid nanoparticle (LNP) system, the relationship between physicochemical properties and in vivo behaviour is more intricate, and the analytical tools needed to characterise it are more demanding.

An LNP that looks identical to a passing batch in a visual inspection can behave very differently in vivo if its particle size distribution has shifted, its encapsulation efficiency has dropped, or its surface charge has changed. The four critical quality attributes discussed in this article, particle size, polydispersity index (PDI), encapsulation efficiency, and zeta potential, are the core measurements that define the identity and performance of an LNP product, and they must be reliably measured and controlled throughout development and into GMP manufacturing.

The 4 Critical Quality Attributes

CQA	What It Measures	Typical Target Range	Why It Matters
Particle size (Z-average)	Mean hydrodynamic diameter of the particle population, measured by DLS	50-200 nm for most therapeutic applications	Size determines circulation time, tissue distribution, and cellular uptake. Particles above 200 nm clear rapidly; below 50 nm may pass through kidney filtration.
Polydispersity index (PDI)	Width of the particle size distribution (0 = monodisperse; 1 = polydisperse)	Below 0.2 for clinical LNP products	High PDI indicates a heterogeneous population. Broader distributions correlate with variable in vivo performance and reduced reproducibility between batches.
Encapsulation efficiency (EE%)	Proportion of the nucleic acid or small molecule payload that is encapsulated within the LNP rather than free in solution	Greater than 85% for mRNA LNPs; target depends on payload and indication	Free (unencapsulated) payload is bioavailable but unprotected, degrades rapidly, and contributes to off-target effects. Low EE% reduces effective dose and increases immunostimulation risk for nucleic acid payloads.
Zeta potential	Net surface charge of the particle at the slipping plane, measured by electrophoretic light scattering	Near-neutral for ionisable LNPs in physiological conditions; negative in buffer (typically minus 5 to minus 20 mV)	Surface charge affects colloidal stability, protein adsorption (corona formation), and cellular uptake. Highly charged particles aggregate more readily and may trigger immune activation.

Target ranges above are representative of typical clinical-stage LNP products based on published literature. Programme-specific specifications must be established based on the molecule and intended clinical use.

Measuring Particle Size and PDI: Dynamic Light Scattering

Dynamic light scattering (DLS) is the standard technique for measuring LNP particle size and PDI. DLS measures the Brownian motion of particles in suspension and uses the diffusion coefficient to calculate the hydrodynamic diameter via the Stokes-Einstein equation. It is fast, non-destructive, and highly sensitive to small shifts in particle size, making it well suited for both development screening and GMP release testing.

DLS has important limitations. It is an intensity-weighted measurement and is therefore disproportionately sensitive to larger particles, which scatter more light. A small number of aggregates can significantly shift the reported Z-average upward even when the bulk of the population is within specification. For LNP batches where aggregation is a concern, complementary techniques such as nanoparticle tracking analysis (NTA) or asymmetric flow field-flow fractionation (AF4) provide a number-weighted or separated view of the size distribution.

Measuring Encapsulation Efficiency: The RiboGreen Assay

For nucleic acid payloads including mRNA and siRNA, encapsulation efficiency is most commonly measured using the RiboGreen fluorescence assay. The assay compares the fluorescence signal from the nucleic acid in an intact LNP sample (where encapsulated nucleic acid is inaccessible to the dye) with the signal from a sample disrupted with a detergent such as Triton X-100 (where all nucleic acid is accessible). The ratio of the two signals gives the encapsulation efficiency.

For small molecule payloads, encapsulation efficiency is typically measured by separating the encapsulated and free fractions using size exclusion chromatography or ultracentrifugation and then quantifying each fraction by LC-UV or LC-MS/MS.

Integrating CQA Measurement into the Development and GMP Lifecycle

Development Phase

During formulation development, CQA measurements are used to screen formulation variables including lipid ratios, drug-to-lipid ratios, and processing conditions. A design of experiments (DoE) approach linking formulation parameters to CQA outcomes allows the formulation space to be explored efficiently and a robust formulation to be identified before GMP scale-up.

GMP Manufacturing

At GMP manufacturing scale, CQA measurements are used as in-process controls during manufacture and as release tests that every batch must pass before it can be used in a clinical study. The specification ranges for each CQA are derived from the development data, with limits set to ensure that batches released for clinical use are within the range of material that has demonstrated acceptable in vivo performance.

LNP Characterisation at Ardena Oss

Ardena’s GMP nanomedicine facility in Oss is equipped with DLS instruments, RiboGreen assay capability, and the analytical infrastructure needed to characterise LNP products across all four critical quality attributes during development and GMP manufacturing. The analytical team works alongside the formulation scientists to integrate CQA monitoring into the development workflow from early screening batches through to GMP release testing.