Polymorph, Salt & Cocrystal Screening and Selection

Different solid forms (polymorph, cocrystals and salts) of APIs have significant differences in thermodynamics, kinetics, and physical properties, which may affect the stability, production process, dissolution, and bioavailability of APIs and formulations, and thus may affect the safety, efficacy, and quality controllability of drugs. Therefore, screening and selecting the ideal solid form (polymorph, cocrystals and salts) of APIs is crucial for reducing R&D risks, improving success rates, reducing production costs, and improving product quality.

Overall Strategy for Polymorph, Salt & Cocrystal Screening and Selection

If the physical and chemical properties of drug molecules can meet the development needs, priority will be given to using the free form for polymorph screening and selecting the dominant crystal form with excellent physical and chemical properties and scalable process.

The physical and chemical properties of drug molecules such as solubility, stability and bioavailability can be improved through salts/co-crystals.

Process of Polymorph Screening and Selection
When drug molecules crystallize in different crystal forms, their bioavailability, solubility, dissolution rate, chemical and physical stability, melting point and other properties may be different. Excellent polymorph screening and selection is an efficient means to reduce R&D risks, reduce production costs, and improve product quality. 

Obtain basic information about drug molecules

Approximate solubility test
Choose appropriate solvent system and crystallization method
Preliminary crystal form screening
Scale-up preparation of dominant crystal forms
Crystal form evaluationMutual transformation relationship, stability, hygroscopicity, solubility, pressure and abrasion resistance...

 Process of Salt Screening and Selection
Many APIs are in the form of acids or bases, but in many cases, their physicochemical properties are difficult to meet the requirements for pharmaceutical properties. By selecting the appropriate salt form, many problems in drug development can be solved, and the most reliable method for discovering suitable salt forms is salt screening and selection. Our services include:

Obtain basic information about drug molecules

Analyze structural formula and pKa information
Basic characterization of free forms
Free form solubility test
Choose appropriate counterions and solvents
Preliminary salt form screening
Scale-up preparation of advantageous salt forms
Salt form assessmentStability, hygroscopicity, solubility, crystal morphology...

 Process of Co-crystal Screening and Selection
Co-crystals can significantly improve the physical and chemical properties of APIs without destroying covalent bonds, such as solubility, stability, bioavailability and mechanical properties. In addition, co-crystals also have good applications in masking the taste of drugs, improving drug tableting performance, and expanding production. Co-crystal screening and selection can help us find superior eutectic. Our services include:

Obtain basic information about drug molecules

Approximate solubility test
Select the appropriate FCC and solvent
Preliminary cocrystal screening
Scale-up preparation of advantageous cocrystal
Cocrystal assessmentStability, hygroscopicity, solubility...