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Co-crystals and Novel Polymorphs

Co-Crystal Screening and Characterisation

Identification of the optimized solid form of an API, those with the best physico-chemical properties, was previously restricted to the free active or it’s salts. However, today we can add the option of screening for co-crystals which is a form that consists of two or more components that are solid at room temperature but being different from salts in that no proton is transferred from the acidic to the basic functionality. Co-crystals have different physico-chemical properties than the free active or a salt such as, dissolution rate, solubility, melting point, chemical stability and hygroscopicity, and hence can exhibit more desirable critical quality attributes. CPES scientists have vast knowledge and experience in the discovery of co-crytsals can screen co-formers to identify potential co-crystals via a number of methods, following identification of a co-crystal form our team can characterise the co-crystal and determine it’s physico-chemical properties to identify benefits over the free drug or its salts.

Co crytsals

Stable Novel Polymorphs

Polymorphs are chemically identical, but have different crystal lattice energies, melting points, intrinsic solubilities, rates of dissolution, densities, mechanical properties, chemical and physical stability, hygroscopicity, etc.

Polymorphism has implications in biopharmaceutical properties, formulation/processing aspects and intellectual property considerations.

The different intrinsic solubilities may lead to differences in the rate of absorption – i.e. have therapeutic implications.

Scientists at CPES have developed a novel method to prepare metastable polymorphs that do not covert back to the thermodynamically stable polymorph over a long period of time under accelerated storage conditions. The stable polymorph have been shown to have desirable quality attributes and may be used to develop a superior drug product, for example it has a significantly greater aqueous solubility and dissolution rate.