Effects of plasticizers and surfactants on the film forming properties of hydroxypropyl methylcellulose for the coating of diclofenac sodium tablets

Hydroxy propyl methyl cellulose (HPMC) 5cPs, an aqueous soluble polymer was employed for coating diclofenac sodium (DFS) tablets 25 mg for protecting the integrity of the drug yet rendering the drug to release at a faster rate on contact with the gastric environment. Proper optimization for the aqueous based film coating formulation was undertaken primarily employing plasticizers like polyethylene glycol (PEG) 400 and propylene glycol (PG). The defect free selected formulations were further subjected for studying the effects of surfactants like sodium lauryl sulphate (SLS) and Tween-80 along with the plasticizers. The quality of the aqueous film coats or the plasticizer efficiency in case of PEG-400 is in the order 1.5 > 0.5 > 1.0% and for PG 1 > 4 > 3% which can be stated on the basis of less incidence of major coat defects like chipping, cracking, orange peel, roughness, blistering, blooming, picking. The quality of aqueous film coat or the surfactant efficiency in case of SLS + PEG-400 is in the order 0.3 < 0.5 < 0.1% and SLS + PG is in the order 0.5 < 0.1 < 0.3%. In case of Tween-80 + PEG-400 the order is 0.3 < 0.5 < 0.1% and Tween-80 + PG is in the order 0.3 < 0.1 < 0.5%. Elegant film formation can be stated from fewer incidences of coat defects. The obtained coated tablets eventually satisfied all the normal physical parameters like thickness, weights, and weight gain, drug content, crushing strength, percent friability, disintegration time, dissolution profile and possible drug–polymer interactions. ANOVA was undertaken followed by Dunnet multiple comparison for the dissolution profile considering uncoated as the standard. The difference was considered significant at p ⩽ 0.01.