Issue link: https://www.e-digitaleditions.com/i/870536
D Tablets & Capsules September 2017 39 liquid-filled capsules Liquid-filled hard capsules help meet today's formulation challenges Jnanadeva Bhat, Fernando Diez, and Justin Kalafat ACG While liquid-filled capsule products are not new, they continue to play an important role in the delivery of poorly bioavailable and highly potent APIs. This article provides an overview and summarizes some recent developments. rug discovery and development have undergone astounding changes in the last few decades, fueled by advances in many areas. Among the most important are cell and molecular biology, recombinant DNA technol- ogy, genomics, proteomics, and biochemical and chemi- cal informatics. Better laboratory instruments and automation have also contributed. Likewise, more effi- cient manufacturing technologies and processes have led to the creation of purer and more potent active pharma- ceutical ingredients (APIs). Figure 1 illustrates how the structural complexity and chemical properties of today's APIs compare to substances discovered decades earlier. The oral absorption of an API is fundamentally depen- dent on the API's aqueous solubility and gastrointestinal permeability. Extensive research into these fundamental properties led to the Biopharmaceutics Classification Systems (BCS), which categorizes APIs into four groups, Class I to Class IV (Figure 2). The BCS assesses com- pounds based on factors related to oral absorption and on