Covalent polybenzimidazole-based triazine frameworks: A robust carrier for non-steroidal anti-inflammatory drugs

Covalent triazine-based polymers (CTPs) are a new class of porous materials that can be used for the intercalation of therapeutic agents. The main purposes of designing new drug carriers include protecting them from degradation, enhancing their poor aqueous solubility, and investigating their controlled release properties. In this context, a novel polybenzimidazole-based CTP (BZ-CTP) was prepared by a solvothermal reaction between 4,4',4″-((1,3,5-triazine-2,4,6-triyl) tris(azanediyl)) tribenzoic acid (TCA) and 3,3'-diaminobenzidine. Piroxicam (PRX) and mefenamic acid (MFA) were loaded thoroughly into the CTP by using ultrasonication to form MFA-loaded CTP (MFA@BZ-CTP) and PRX-loaded CTP (PRX@BZ-CTP) with drug loading efficiencies of 49% and 53%, respectively. We attribute the increased loading efficiencies to the formation of π-π stacking forces between the aromatic rings present in the CTP structure and drugs. The in vitro release experiments were assessed in simulated physiological conditions using the dialysis method. Moreover, the release mechanisms were evaluated by Korsmeyer-Peppas kinetic studies and the obtained results showed excellent sustained releases of 81% after 96 h and 87% after 24 h for the PRX@BZ-CTP and MFA@BZ-CTP hybrids, respectively.