Solubility enhancement of olmesartan medoximil by spray drying technique

Olmesartan medoxomil (OM) is an angiotensin II receptor blocker. It is practically insoluble in water and has an oral bioavailability of 26% with a terminal half life of approximately 13 hours. In the present study, a spray drying technique has been used to prepare solid dispersion (SD) of OM with Polyvinyl pyrrolidone (PVP K) 30 and Gelucire® 50/13 with silicon dioxide (Aerosil®200) as carrier to improve drug solubility. The SDs were characterized in comparison with pure drug and corresponding Physical mixture (PM) in the same ratio by using drug content, saturation solubility, scanning electron microscopy (SEM), diffuse reflectance infrared transform spectroscopy (DRIFTS), X-ray powder diffraction (XRPD) and in vitro drug release. SDs were further subjected to aging at room temperature (300C / 60% RH) for three months and characterized for in vitro drug release and presence of crystallanity using XRPD.Absence of pure OM peaks in XRPD suggests transformation of crystalline OM into an amorphous form. DRIFT spectra revealed presence of hydrogen bonding interactions in solid dispersion. Significant improvement in dissolution of SDOMGA compared to SDOMP, crystalline OM, spray dried OM, and physical mixtures of drug with carrier. Therefore solid dispersion by spray drying with multifunctional excipient Gelucire® 50/13 can stabilize OM in amorphous form, improve solubility and prevent hydrolysis providing better alternative to conventional stabilizers like PVPK30.

Author(s): Kirti K. Kamble

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