Sustained Delivery of Pyridostigmine Bromide from Thermosensitive Chitosan/GP Hydrogel

Pyridostigmine bromide (PB) is a carbamate derivative of reversible acetylcholinesterase (AChE) inhibitor that has some properties, such as high water-solubility, high hygroscopiccharacter (its rapid transformation from solid to liquid state under ambient condition), short elimination half time (1~ 2 hr)and exhibition of side effects [1]. The approved dose of PB for pretreatment to protect against Soman is one 30 mg of it’s tablet every 8 hr, while the there is only a 180 mg of extendedrelease coated tablet (Mestinon®) on the pharmaceutical market for twice-daily administration against myastheniagravis. So, the need to maintain an 8 hr schedule of PB under the conditions of actual or anticipated combat stress is a majorpractical deficiency in medical defense against nerve agents. In this work a new sustained PB delivery formulation based on injectable chitosan/glycerolphosphate solution, which couldprotect the drug from hydrolysis and control its release over a prolonged period; is proposed, and it’s in vitro release pattern was evaluated