New Strategies for Improving the Solubility of Poorly Water-Soluble Drugs: A Comprehensive Review

Abstract

A drug's solubility and bioavailability are crucial determinants of its therapeutic success, particularly when taken orally. Less than 10% of new drug candidates have exhibited good solubility and permeability, while 40% of pharmaceuticals cause low water solubility and side effects such as stomach irritation and peptic ulcers. Solubility affects the rate of dissolution, absorption, distribution, and excretion of drugs. Recent innovations in solubility improvement techniques aim to overcome low solubility in medications. Steam-aided granulation creates a porous structure that enhances solubility and bioavailability by using steam to granulate the drug substance. Solid dispersion disperses the drug in a polymer matrix to improve solubility. Floating granulation combines the drug with a hydrophobic material that floats in the stomach for sustained-release effects and better bioavailability. Spherical agglomeration forms spherical agglomerates by combining the drug with a binder and solvent, thereby reducing the particle size and increasing surface area. Liquisolid technology converts the drug substance into a free-flowing powder and forms a paste-like material with liquid, creating a porous structure that enhances absorption. Cryo techniques use low temperatures to improve solubility through spray freezing, freeze-drying, and spray drying. Sono crystallisation employs ultrasound waves to induce crystallization and enhance solubility. In summary, solubility and bioavailability are critical to a drug's therapeutic success, and recent solubility improvement techniques, such as steam-aided granulation, solid dispersion, floating granulation, spherical agglomeration, liquisolid technology, cryo techniques, and sono crystallisation, can enhance drug solubility and bioavailability.