Tuning the pH-sensitive cationic nanopolymers for in vitro release of doxorubicin

In the present study, Chitosan (CS) along with N-isopropyl acrylamide (NIPAAM) and 2-(Di isopropyl amino) ethyl methacrylate (DPA), were used to synthesize polymeric nanoparticles (PNPs) for delivering Doxorubicin (DOX) (having anti-cancer effects) at the malignant site. In the FTIR spectrum, peaks of OH at 3411 cm(-1), N-H at 1534 cm(-1), and C=O at 1630 cm(-1) confirmed the presence of constituent molecules in the PNPs while appearance of no peak between 3000 to 3100 cm(-1) depicted successful free radical polymerization through cleavage of double bond. The semi-circular appearance with 251 nm average particle size was confirmed through SEM analysis. The thermal stability was quantified by TGA i.e., no considerable degradation up to 97 degrees C. The amorphous nature was determined by the XRD pattern of PNPs at 2 Theta. The MTT assay of DOX-loaded PNPs showed 88.5% cell inhibition. At an acidic pH of 5.3, a maximum of 243% swelling was achieved in 80 hours as compared to 140% and 73% swelling at pH 6.5 and pH 7.4 respectively. The DOX loading was found to be maximum at 85.6% (4.28 mg/5 mg) of the drug feed in solution. There was a more prominent 81% (3.46 mg/4.28) DOX release at the internal pH of tumor cells i.e., 5.3.