Challenges to improve the biopharmaceutical properties of poorly water-soluble drugs and the application of the solid dispersion technology

The oral solid dosage forms are extremely relevant to drug therapy and responsible for much of the pharmaceutical industry turnover worldwide. However, the development of medicines in solid form involves significant challenges, including obtaining formulations with appropriate bioavailability for low aqueous solubility drugs (classes II and IV of the Biopharmaceutics Classification System). One of the most effective strategies to overcome poor dissolution rate and low absorption of drugs is the solid dispersion technique, however, although it has been the focus of much research in recent decades, there are relatively few commercially available products based on such technology. This is mainly due to problems related to production scale-up and physicochemical instability and creates opportunities for new studies to explore the full potential of the technology. This review presents an overall approach to the factors affecting the dissolution rate and oral bioavailability of BCS-classes II and IV drugs and a brief review of the state-of-the-art of solid dispersion technology.