Acrylamide grafted neem (Azadirachta indica) gum polymer: Screening and exploration as a drug release retardant for tablet formulation

The study was initiated with the intent to synthesize acrylamide grafted neem gum polymer (AAm-g-NG), and screen its drug release retardation ability both in vitro and in vivo. Different batches (NGP-1 to NGP-9) of tablet formulation were prepared by varying polymer concentration using propranolol HCl and compared with HPMC K100M and marketed SR tablets. FTIR study proved the grafting phenomenon and showed no incompatibility between AAm-g-NG and propranolol HCl. AAm-g-NG showed significant swelling and water retention capacity than NG. AAm-g-NG was found to be biodegradable and exhibited no toxicity to Artemia salina. After 12 h, NGP-6 showed non-significant (p > 0.05; f(2)= similar to 90) percent drug release (80.52 +/- 3.41%) compare to marketed formulation (79.65 +/- 4.08%). Significant swelling of the matrix caused slower diffusion of the drug. NGP-6 and marketed formulation in rabbits showed the non-significant difference between C-max and T-max, hence NGP-6 meets the requirement of sustained-release tablets.