N-Trimethyl chitosan-coated multivesicular liposomes for oxymatrine oral delivery

Background: Multivesicular liposomes (MVLs), uncoated and coated with N-trimethyl chitosan (TMC), have been studied for their potential use for drug delivery by the oral route. Method: Synthesized TMC was characterized by infrared spectroscopy, revealing the presence of trimethyl groups, and by proton nuclear magnetic resonance spectroscopy, allowing the calculation of the degree of substitution quaternization (70.2%). Oxymatrine (OM), a natural quinolizidine alkaloid used clinically for treating hepatitis B, was chosen as a model drug. The surface-modified MVLs and uncoated MVLs were characterized in vitro in terms of their shape, size, zeta potential, entrapment efficiency, coating efficiency, the stability of MVLs in polymer suspension, and the stability in simulated gastric and intestinal fluids. Results: In vivo, the area under the plasma concentration-time curve obtained from the pharmacokinetics study of TMC-coated MVLs was found to be about 3.26- and 1.96-fold higher than that of OM solution and uncoated MVLs, respectively. Conclusion: TMC-coated MVLs can be considered as a potential carrier for oral drug administration.