Enhancement of the Solubility of Simvastatin by Utilizing Two Distinct Types of Excipient Compositions, L-Isoleucine and Sodium Docusate

Simvastatin is a BCS class II drug, which means it has high absorbability but low solubility. The solubility of a drug plays an important role in determining its bioavailability and the effect that it has on the body as a whole. The study objective was to increase the solubility of simvastatin by using two excipients: sodium docusate and L-isoleucine. These excipients were incorporated in a solid dispersion at different ratios, left to dry, dissolved, and tested for increased solubility against a simvastatin calibration curve (which was prepared using a standard solution of simvastatin). The improvement in solubility for a 4:1:1 ratio was 1.49-fold. A 2:1:1 ratio of simvastatin: docusate: isoleucine was increased 7.18-fold, and a 4:3:3 ratio increased the solubility 4.81-fold. The synergistic effect of docusate and isoleucine showed improvement in the solubility of simvastatin at room temperature when incorporated in relatively low ratios.