Pharmaceutical Characterization of MyoNovin, a Novel Skeletal Muscle Regenerator: in silico, in vitro and in vivo Studies.

PURPOSE: MyoNovin is a novel skeletal muscle-regenerating compound developed through synthesis of two nitro groups onto a guaifenesin backbone to deliver nitric oxide to skeletal muscle with a potential to treat muscle atrophy. The purpose of this study was to utilize in silico, in vitro, and in vivo approaches to characterize MyoNovin and examine its safety, biodistribution, and feasibility for drug delivery. METHODS: In silico software packages were used to predict the physicochemical and biopharmaceutical properties of MyoNovin. In vitro cardiotoxicity was assessed using human cardiomyocytes (RL-14) while effects on CYP3A4 metabolic enzyme and antioxidant activity were examined using commercial kits. A novel HPLC assay was developed to measure MyoNovin concentration in serum, and delineate initial pharmacokinetic and acute toxicity after intravenous administration (20 mg/kg) to male Sprague-Dawley rats. RESULTS: MyoNovin showed relatively high lipophilicity with a LogP value of 3.49, a 20-fold higher skin permeability (19.89 cm/s*10(7)) compared to guaifenesin (0.66 cm/s*10(7)), and similar to 10-fold higher effective jejunal permeability (2.24 cm/s*10(4)) compared to guaifenesin (0.26 cm/s*10(4)). In vitro, MyoNovin was not cytotoxic to cardiomyocytes at concentrations below 8 mu M and did not inhibit CYP3A4 or show antioxidant activity. In vivo, MyoNovin had a short half-life (t(1/2)) of 0.16 h, and a volume of distribution V-ss of 0.62 L/kg. Biomarkers of MyoNovin cardiac and renal toxicity did not differ significantly from baseline control levels. CONCLUSIONS: The predicted high lipophilicity and skin permeability of MyoNovin render it a potential candidate for transdermal administration while its favourable intestinal permeation suggests it may be suitable for oral administration. Pharmacokinetics following IV administration of MyoNovin were delineated for the first time in a rat model. Preliminary single 20 mg/kg dose assessment of MyoNovin suggest no influence on cardiac troponin or beta-N-Acetylglucosaminidase.