Advances in Solid Dispersion Techniques for Enhancing Drug Solubility, Bioavailability and Controlled Release

Solid dispersion (SD) refers to the dispersion of active ingredients, whether one or more, within inert carriers in a solid state. This is achieved through methods like fusion, solvent, or solvent fusion. The solid dispersion technique is particularly valuable for enhancing the solubility of inadequately soluble drugs, particularly those falling under BCS Class II. This technique involves the utilization of carriers such as polyethylene glycol 4000, urea, and polyvinylpyrrolidone K 30 to improve the drug's solubility and dissolution properties. The method of solid dispersion has been utilized to improve the solubility, dissolution, and bioavailability of various natural drug components. Furthermore, solid dispersion has been investigated as a strategy for developing natural drug products with controlled or sustained release characteristics. The mechanism of action of this delivery system relies on the specific type of solid dispersion, as well as the interactions among the drugs, carriers, and other components incorporated into the formulation. Currently, there are various methods accessible for characterizing SDs, including X-ray diffraction, differential scanning calorimetry, FTIR spectroscopy, and dissolution testing, among others. The pharmaceutical uses of the Solid Dispersion technique encompass: augmenting drug absorption, achieving a uniform distribution of a small drug quantity in a solid state, and safeguarding unstable drugs by mitigating processes like hydrolysis, oxidation, and photooxidation