The impact of polymer blends and solid dispersion technologies on drug release rates

The objective of this research was to investigate the impact of polymer blends and solid dispersion formulation technologies on drug forms and release rates. An hydrophobic carrier, poly(methyl methacrylate PMMA), an hydrophilic carrier Eudragit EPO, together with an hydrophobic drug indomethacin (INDO), were used to produce various dispersion formulations through hot melt mixing (HMM) and solvent evaporation methods. Characterization of the various solid dispersion formulations was performed using standard analytical methods such as differential scanning calorimetry (DSC), polarized light microscopy (PLM), environmental scanning electron microscopy (ESEM), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR). The results obtained from the various characterizations suggest that the drug was molecularly dispersed in the polymer matrices. In-vitro dissolution studies were carried out in simple model gastric fluid (pH 1.2) and also in phosphate buffer dissolution medium (pH 7.2). Approximately, 19.79 % of the INDO contained in the HMM formulation comprising PMMA 70 EPO 10 INDO 20 by weight percent was released in approximately 30 minutes while about 54% of the solvent evaporation formulation (PMMA 70 EPO 10 INDO 20) was released after 22 hours. Dissolution results demonstrated that a combination of hydrophobic and hydrophilic polymers will effectively sustain the drug release for a prolonged period of time depending on the formulation composition and the solid dispersion technology employed to produce it.