Investigation of polyethylene oxide-based prolonged release solid dispersion containing isradipine

The aim of the study was to press a synergistic act of a formulation: (1) enhancing the dissolution rate of a poorly water-soluble drug; (2) controlling the release rate of the drug. There is still little published research on such a formulation. The model drug used in the current study is isradipine (IS), a calcium channel blocker of the dihydropyridine class. To fulfill the expected target, solid dispersion containing IS was first prepared with the carrier polyethylene glycol 6000 (PEG 6000) with the melting method and then polyethylene oxide N-60K (PEO N-60K) was utilized to induce drug release in a controlled manner. Physicochemical properties of the solid dispersion and physical mixture were characterized by powder x-ray diffraction (PXRD) and Fourier transform infrared (FTIR) spectroscopy to investigate the structural behavior of drug and IS-PEG interactions, respectively. Preparation of such a formulation not only enhanced but also controlled the drug dissolution rate in both simulated gastric (pH 1.2) and intestinal (pH 6.8) media. This result should be a consideration for pharmaceutical scientists in maintaining the desired blood levels of drugs with narrow therapeutic fluctuation ranges for extended periods of time after a single administration.