Mechanism for improving the dissolution rate of poorly soluble acidic drugs using poly-γ-glutamic acid and the formulation of poly-γ-glutamic acid-coated particles to improve dissolution rate

Abstract

For poorly soluble drugs, formulations designed to improve their solubility are needed in order to ensure effective blood concentrations are achieved after oral administration. In this study, we developed a new solubilization method for poorly soluble acidic drugs using poly-γ-glutamic acid (PGA). The drugs were released from drug/PGA mixed powders more rapidly than from drug bulk powders. This rapid drug release was thought to be due to molecular interactions between PGA and the drugs when they were dissolving. From these results, it was considered that PGA-coated drug particles were useful for improving the dissolution rate of the drug. PGA-coated drug particles were prepared using indomethacin and warfarin, and rapid drug release from the PGA-coated drug particles was confirmed. The optimum amount of PGA for drug coating was examined, and it was suggested that acceptable particles may be prepared by adding 50 mg PGA potassium salt to 100 mg of drug.