Development of polymeric IPN hydrogels by free radical polymerization technique for extended release of letrozole: Characterization and toxicity evaluation

This research study’s objective was to formulate interpenetrating pH-sensitive polymeric networks interpenetrating networks (IPNs) based on hydroxypropylmethylcellulose (HPMC)/Primojel for use in the treatment of various malignant conditions. For controlled release, letrozole (LTZ) was selected as a model drug in HPMC and Primojel-based IPN hydrogels. HPMC and Primojel based IPN hydrogels were fabricated through the free radical polymerization method by utilizing HPMC and Primojel as polymers, methacrylic acid as monomer, ammonium persulfate as initiator, and methylenebisacrylamide as cross-linker. For structural characterization, various techniques such as Fourier transform infrared spectroscopy, Scanning electron microscopy (SEM), DSC, TGA, and Powder x-ray diffraction (PXRD) were applied to IPN samples. In vitro and swelling studies were also employed to observe the response of these polymeric networks against 1.2 and 7.4 pH. TGA and DSC of an optimized loaded formulation possess better thermal stability as compared to individual drug. PXRD depicted minor crystallinity and a significant amorphous nature. SEM images show that polymeric networks possess an uneven and porous surface. Significant swelling and enhanced in-vitro outcomes at a high pH of 7.4 confirmed the IPN pH responsive properties. Toxicological studies performed on rabbits revealed no harm in the results. Thus, IPN based on HPMC/Primojel was successfully synthesized and can be used for LTZ’s controlled release.