Imine-Linked Covalent Organic Frameworks: A Biocompatible and pH-Dependent Carrier for In Vitro Sustained Release of Doxorubicin.

Among the novel drug delivery systems (DDSs), covalent organic frameworks (COFs) show promising features in pharmaceutical science. In this paper, an imine-linked COF with hexagonal topology was synthesized using the autoclave condition. Then, the prepared COF (APB-COF) was used as a pH-dependent carrier for in vitro release of doxorubicin (DOX). The intrinsic properties of APB-COF caused reaching an excellent drug encapsulation efficiency. DOX@APB-COF shows an exemplary pH-dependent release in two different pHs. DOX release at pH = 7.4 was 32%, which increased to 54% by changing the pH to the cancer cell pH (pH = 5.4). Moreover, the cytotoxicity of APB-COF and DOX@APB-COF was studied using the standard MTT test against MCF10 (normal breast cell line) and MDAmb231 cells (breast cancer cell line), respectively. It was observed that the APB-COF does not affect cell proliferation, whereas the DOX@APB-COF only limits cancer cell proliferation. Using APB-COF as the drug carrier can pave the way for using COFs in innovative DDSs.

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.