Preparation and In Vitro/In Vivo Characterization of Polymeric Nanoparticles Containing Methotrexate to Improve Lymphatic Delivery

Methotrexate (MTX) is a folic acid antagonist used as an effective drug to treat various kinds of cancers. However, MTX has limited use in cancer chemotherapy due to its adverse effects such as poor bioavailability, low specificity, drug resistance, and dose-dependent side effects. To improve lymphatic delivery and reduce toxicity of MTX, MTX-loaded nanoparticles (NPs) were prepared in the present study. NPs were prepared with double emulsion solvent evaporation method using poly(lactide-co-glycolide) (PLGA). NPs were assessed for size, encapsulation efficiency, morphology, Fourier-transform infrared spectroscopy, X-ray diffraction, and thermal characterization. In vitro release profiles and cytotoxicity of these NPs were also evaluated. Prepared NPs and free MTX were administered orally or intravenously (5 mg/kg as MTX) to rats to evaluate their pharmacokinetic characteristics and lymphatic delivery effects. Mean particle size and encapsulation efficiency of NPs were 163.7 ± 10.25 nm and 93.3 ± 0.5%, respectively. Prepared NPs showed a sustained release profile of MTX in vitro and may be effective to cancer cells. Area under the blood concentration-time curve, total clearance, half-life, and lymphatic targeting efficiency were significantly different (p < 0.05) between prepared NPs and free MTX. These results demonstrate that MTX-loaded PLGA NPs are good candidates for targeted delivery of MTX to the lymphatic system.