Competitive inhibition of nicotine acetylcholine receptors using microneedles of nicotine and varenicline for smoking withdrawal therapy

Current strategies for smoking withdrawal conditions involve monotherapy of nicotine and combinational therapy of nicotine with varenicline or bupropion as per the CDC and FDA. The available dosage forms for nicotine are patches, gums, inhalers and nasal sprays, bupropion and varenicline are available in tablet form. This research work focused on developing a microneedle delivery system to deliver combination drug for overcoming the obstacles encountered by oral route of administration of varenicline such as severe side effects (mood swings, agitation, depressed behaviour, seizures, etc), and nicotine therapy challenges such as short halflife, repeated dosing, nausea, and vomiting. The nanoparticles of nicotine prepared by nanoprecipitation method showed particle size PTZ (356.6 +/- 65.98), percentage entrapment efficiency (35.55 % +/- 0.007), in -vitro drug release (47.89 % +/- 0.7) for 72 h. Microneedles showed height (600 mu m), width (350 mu m), and tip diameter (10 mu m). The nanoparticles encapsulated in microneedles showed in -vitro sustained delivery of nicotine (67.00 % +/- 4.92) and varenicline (79.78 % +/- 1.09) in 48 h. Nicotine released in a sustained manner attaches to the nicotine acetylcholine receptors (nAchR) to release dopamine for controlling the withdrawal challenges such as anxiety, irritability, cravings, disturbed sleep pattern, etc. The varenicline released from microneedles binds to the nAchR and inhibits dopamine release responsible for the euphoric effect induced by nicotine, and thus assists in curbing the nicotine withdrawal symptoms. This combination microneedle system offers prolonged treatment in a single application for smoking withdrawal conditions wherein patients are not in stage of oral dosing because of repeated dosing resulting in adverse effects like seizures, hypertension, sleep disturbances, insomnia, and nausea.