Solid state properties – salt selection

The vast majority of APIs exist as weak acids or weak bases. This gives the opportunity to alter the physic-chemical properties of the material by forming a salt.

Most often the goal of salt formation is to enhance dissolution rate, but sometimes it can be to enhance stability by reducing hygroscopicity of a compound.

As for different polymorphs, different salts can have very different physic-chemical properties. The selection of a suitable salt is often one of the first things to consider when developing a new chemical entity, as it can enhance the prospect of systemic exposure during clinical trials.

Salts are usually formed with acceptable co-formers (acids or bases) that have been used previously in marketed products intended for the same route of administration.

Consultancy is available for
• selecting the most appropriate salt screening strategy
• outsource company selection and management
• data interpretation

The goal is to fit the salt selection strategy into the overall product development strategy to get the product of suitable quality in the shortest possible development time.

Back to Solid State