Naproxen-Loaded Poly(2-hydroxyalkyl methacrylates): Preparation and Drug Release Dynamics.

Poly(2-hydroxyethylmethacrylate)/Naproxen (NPX/pHEMA) and poly (2-hydroxypropyl methacrylate)/Naproxen (NPX/pHPMA) composites with different NPX content were prepared in situ by free radical photopolymerization route. The resulted hybrid materials were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning Electron microscopy (SEM), and X-ray diffraction (XRD). These composites have been studied as drug carrier systems, in which a comparison of the in vitro release dynamic of NPX between the two drug carrier systems has been conducted. Different factors affecting the performance of the release dynamic of this drug, such as the amount of Naproxen incorporated in the drug carrier system, the pH of the medium and the degree of swelling, have been investigated. The results of the swelling study of pHEMA and pHPMA in different media pHs revealed that the diffusion of water molecules through both polymer samples obeys the Fickian model. The "in vitro" study of the release dynamic of Naproxen from NPX/pHEMA and NPX/pHPMA drug carrier systems revealed that the higher percentage of NPX released was obtained from each polymer carrier in neutral pH medium, and the diffusion of NPX trough these polymer matrices also obeys the Fickian model. It was also found that the less the mass percent of NPX in the composites, the better its release will be. The comparison between the two drug carrier systems revealed that the pHEMA leads to the best performance in the release dynamic of NPX. Regarding Naproxen solubility in water, the results deducted from the "in vitro" study of NPX/pHEMA10 and NPX/pHPMA10 drug carrier systems revealed a very significant improvement in the solubility of NPX in media pH1 (2.33 times, 1.43 times) and 7 (3.32 times, 2.60 times), respectively, compared to those obtained by direct dissolution of Naproxen powder.