Solid form screening, including salt, polymorph, cocrystal and amorphous solid dispersions, is vital for successful pharmaceutical development. With an increase in molecule size and complexity, companies face a larger number of compounds that are either poorly soluble, difficult to crystallise or problematic with respect to desired physical chemical properties. Our solid state research team has expertise in identifying new crystal forms as well as in solving problems related to polymorphism and crystallisation.
Our solid form screening expertise includes:
Physicochemical properties of drug substances, such as solubility, dissolution rate and physicochemical stability can be altered significantly by salt formation. Consequently, important properties of the drug product such as bioavailability and shelve life can be radically influenced. Our technology platform for crystallisation screening accommodates high-throughput salt screening studies using only minimal amounts of drug substance. Salt screening is used for both early phase salt selection studies and broad patent protection.
Cocrystals provide opportunities to alter the physicochemical properties of the drug substance or to crystallise compounds. The ability of a drug substance to form a cocrystal depends on a range of variables, with the most important being the number of H-bonding donors or acceptors and its sterical properties. By systematically exploring the combination of relevant variables, we increase the chance of discovering a cocrystal with the desired properties. Our in-depth crystallisation expertise, rational design of experiments and proprietary high-throughput technologies, mean we can successfully identify and characterise cocrystals.
For regulatory purposes, companies must demonstrate that they have made a reasonable effort to identify the polymorphs of their drug substance and have checked for polymorph interconversions. Due to the unpredictable behaviour of polymorphs and their different physicochemical properties, companies also have to demonstrate consistency in manufacturing between batches of the same product.
Our unique polymorph screening methodology enhances understanding of the polymorphic behaviour of drug candidates. The scope and size of studies range from small screens for initial indication of polymorphism to large screens for intellectual property use. Our polymorph screening services use proprietary high-throughput crystallisation technology, with the capability to perform more than 1000 screening experiments using only a few grams of drug substance.
Amorphous solid dispersion screening
Using the amorphous form of a drug substance offers several advantages in terms of dissolution rate and solubility. However, reduced chemical stability, increased hygroscopicity and physical instability are the major drawbacks of using the amorphous phase in the final drug product. This creates the need to stabilise the amorphous phase of the API in a polymer matrix, e.q. an amorphous solid dispersion.
A variety of factors contribute to the formation of a suitable Amorphous Solid Dispersion (ASD), including the nature of the polymer, the drug polymer ratio, the impact of surfactants and the solvent used in the process. We have developed high-throughput solid dispersion screening technology in order to find the optimal combination of these factors.