Enhancement of Solubility and Dissolution Rate of BCS Class II Drugs

Abstract

The enhancement of solubility and dissolution rate is a critical aspect of pharmaceutical development, particularly for Biopharmaceutical Classification System (BCS) Class II drugs characterized by low solubility and high permeability. This review provides an extensive overview of techniques and strategies employed to address the challenges associated with these drugs, aiming to improve their bioavailability and therapeutic efficacy. The review begins by introducing the Biopharmaceutical Classification System (BCS) and its significance in drug formulation, emphasizing the importance of solubility and dissolution rate in determining oral bioavailability. Challenges associated with BCS Class II drugs are discussed, including formulation difficulties and variability in absorption along the gastrointestinal tract. Various techniques for solubility enhancement are examined, such as particle size reduction, salt formation, solubilization techniques (co-solvency, complexation, micellization), solid dispersion, cyclodextrin complexation, and nanoparticle formulation. Additionally, strategies for dissolution rate enhancement are explored, including nanocrystals, surfactants, spray drying, and porous carriers. Furthermore, the review highlights common assessment techniques for solubility and dissolution rate, both in vitro and in vivo, essential for evaluating the effectiveness of formulation strategies. The importance of these techniques in predicting drug behaviour and refining drug delivery mechanisms is emphasized. Overall, this comprehensive review underscores the significance of enhancing solubility and dissolution rate in pharmaceutical development, particularly for BCS Class II drugs, and provides valuable insights into the diverse strategies and methodologies employed to overcome formulation challenges and improve drug bioavailability and therapeutic outcomes.