Sustained drug delivery of doxorubicin as a function of pH, releasing media, and NCO contents in polyurethane urea elastomers

A novel diamine 4-(4-aminophenoxy)butyl-4-aminophenyl ether (ABAE) was synthesized as a chain extender (CE) by a quick and facile method using microwave reactor. CE was used for the preparation of stimuli-responsive Polyurethane-urea elastomer (PUU) with the ratio of NCO/OH from 2 to 2.5. Synthesized PUU was characterized with the help of Fourier transform infrared spectroscopy (FTIR), derivative thermogravimetric analysis (DTG), and scanning electron microscopy SEM. PUU films were loaded with an anti-cancer drug “doxorubicin”. Drug release kinetics were studied in different solvents, at different pH values and with different NCO contents of PUU. The maximum of 45% cumulative drug release was observed in DMSO while the drug release increased with the decrease in pH and a maximum cumulative release of 47% was observed at acidic pH of 4.4. The minimum drug was released from the one, which was crosslinked with highest ratio (2.5) of NCO/OH. So, we can say that drug release can easily be adjusted under different conditions and environments with the help of these stimuli-responsive media.