Drug Solubility

An Ongoing Issue in Drug Development

Solubility is a major challenge in the development of drug formulations. Drugs that are not water-soluble cannot be easily delivered through the bloodstream to targeted tissues. Historically, salts have been used to increase solubility; however, this approach often only provides marginal improvements, particularly with larger, more complex, or highly hydrophobic (water-repelling) molecules. Newer, more effective methods of providing solubility have been successfully applied to commercial products, including the use of lipids, proteins, nanoparticles and mixed-micelles.

Within oncology, emulsifying solvents have typically been used in recent years to improve the solubility of chemotherapeutics. However, while these solvents create water-soluble formulations, many cause toxic side effects limiting the amount of an active drug that can be administered to patients, or may require patients to be pretreated with steroids as well as other medications.