Oral solid dosage forms physicochemical properties

Pharmaceutical excipients available on the market seem sufficient to support typical oral solid dosage form development. In some cases, new chug candidates have physicochemical and biopharmaceutical properties that are less than ideal. These chugs present formulation challenges and may require either the discovery of new excipients or improvement of existing excipients. From a regulatory perspective, there is no answer for the question of registration of an excipient as a separate entity. 

Early on in product development, the potential for the successful development of a solid oral dosage form is assessed, based on the physicochemical properties of the API (1). Prior to solid dosage form development, it is necessary to anticipate the physicochemical properties that can have a major influence on product manufacture and performance. The early development (preformulation and early formulation development) studies should focus on these properties so as to avoid problems at later stages of development. While the molecular properties dictate the intrinsic solubility and the chemical stability of the compound, by controlling the physical form of the compound and by modifying physical properties (e.g., particle size), the dissolution rate can be enhanced with the potential for improving bioavailability. This chapter will focus on physical properties including particle characteristics, and most importantly, the physical form (i.e., solid state) of the API. 

Tan, A., Rao, S., Prestidge, C.A., 2013. Transforminglipid-based oral drug delivery systems into solid dosage forms an overview of solid carriers, physicochemical properties, and biopharmaceutical performance. Pharm. Res. 30, 2993—3017. 

All product characteristics likely to be affected by storage, e.g., assay value or potency, content of products of decomposition, physicochemical properties (hardness, disintegration, particulate matter, etc.), should be determined for solid or semi-solid oral dosage forms, dissolution tests should be carried out... 

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