Direct nose-to-brain delivery of drugs and faster onset of action have made intra-nasal route a much sought-after alternative to conventional routes of drug delivery to the brain. Lamotrigine is used for the treatment and management of neuropathic pain, and in the present work, lamotrigine (LTG)-PLGA nanoparticles were developed for intra-nasal delivery. The LTG-PLGA nanoparticles were prepared using modified nanoprecipitation method via high-speed homogenization and ultra-sonication techniques. Entrapment efficiency (EE%) of developed LTG-PLGA-NPs was found to be 84.87 ± 1.2% with drug loading of 10.21 ± 0.89%. The particle size of developed nanoparticles was found to be 184.6 nm with PDI value of 0.082 and zeta potential of - 18.8 mV. Dissolution profiles were studied in PBS (pH 7.4), simulated nasal fluid, and simulated cerebrospinal fluid where almost complete release was observed within 5 h in CSF. In vitro, cytotoxicity was analyzed using MTT assay where dose-dependent cytotoxicity was observed for developed LTG-PLGA-NPs. In vitro cytokine analysis showed positive effects of LTG-PLGA-NPs as pro-inflammatory cytokine suppressors. Further, in vivo studies were performed for radiolabeled formulation and drug (99mTc-LTG-PLGA-NPs and 99mTc-LTG-aqueous) using Sprague Dawley rats where with the help of gamma scintigraphy studies, various routes of administration viz. oral, intra-nasal, and intra-venous were compared. Various pharmacokinetic parameters were evaluated using biodistribution studies to estimate the drug levels in blood and brain. For 99mTc-LTG-PLGA-NPs via intra-nasal route, drug targeting efficiency (DTE%) was found to be 129.81% and drug target organ transport (DTP%) to be 22.81% in brain with Cmax of 3.82%/g within Tmax 1.5 h. Thus, the developed PLGA nanoparticles for intra-nasal delivery provide a possible alternative for existing available drug formulation for neuropathic pain management.
Keywords: Biodistribution; Gamma scintigraphy; Lamotrigine; Nanoparticles; PLGA.