Managing Poor Solubility With Cutting-Edge Formulation Approaches

By Nathan Dormer, Ph.D., Director of Drug Product Development, Adare Pharma Solutions

Current drug discovery and computational modeling efforts are focused on identifying molecules with the physiological and chemical properties needed to target highly complex disease states. While this prioritization is key to uncovering the new chemical entities (NCEs) that will serve as the foundation for transformative therapies, it often comes at the expense of other properties integral to the bioavailability of a drug. Chief among these is its solubility, as an increasing number of poorly-soluble active pharmaceutical ingredients (APIs) are the cornerstone of cutting-edge therapies. Thus, equally complex formulation technologies are needed to maintain or improve solubility with the ultimate goal of improving bioavailability.

Improvements in a drug's rate of onset and therapeutic levels can often be realized by controlling and improving the distribution of drug into the bloodstream and tissues. Formulation techniques that address one or more facets of the "big picture" (solubility, permeability, and bioavailability) are likely to have the most commercial success. Comparatively, it is "easier" to tailor a drug's final dosage form to increase solubility than it is to develop or discover highly-soluble molecules with targeted therapeutic effect. A wealth of novel excipients, newer solubilization techniques such as amorphous solid dispersions, and a range of other compounding and manufacturing techniques have emerged as solutions to these challenges; finding the right contract development and manufacturing organization (CDMO) to successfully apply appropriate formulation techniques is critical to a drug's commercial success.

Finding the right formulation comes down to a fundamental understanding of the physicochemical properties of the molecule itself and the delivery amount and rate needed for a desired therapeutic effect. The ultimate arbiter of final formulation is dosage size; other factors, such as taste masking or swallowability, are addressed once the bioavailability of a drug has been optimized through appropriate formulation technology selection.