Enhancing the Solubility of BCS Class IV Antibiotics to Unleash Their Potential

Water solubility is a key physicochemical property during drug development, yet about 90% of new drug candidates exhibit low solubility. Numerous approaches have been proposed to enhance drug solubility, including physical modification and the use of solubilizing agents, formulation modifications, and nanotechnology techniques. Increasing both the solubility and dissolution rate of the drug substance is an important element of drug formulation technology, aimed at improving therapeutic efficacy and bringing economic benefits—both in the production process and by reducing the cost of therapy for the patient. Moreover, enhancing solubility helps reduce dosing, which is key to combating antibiotic overuse and resistance. This article reviews the newest methods and effects for increasing solubility and the dissolution rate of antibacterial substances in biopharmaceutics classification system (BCS) class IV, characterized by low water solubility and limited intestinal permeability. Particular attention was paid to summarizing the newest strategies to guide future formulation development and critically evaluate the literature.