Evaluation of extemporaneously manufactured topical gels containing aceclofenac on inflammation and hyperalgesia in rats

The systemic use of non-steroidal anti-inflammatory drugs (NSAIDs) which act by inhibiting cyclooxygenase (COX) is severely hampered by gastric and peptic ulcers. The topical delivery of NSAIDs has the advantages of avoiding gastric and peptic ulcers and delivering the drug to the inflammation site. Importance of aceclofenac as a new generational NSAID has inspired the development of topical dosage forms. This mode of administration may help to avoid typical side effects of NSAIDs associated with oral and systemic administration such as gastric irritation, particularly diarrhoea, nausea, abdominal pain and flatulence. The aim of this study was to formulate topical gel containing 1% of aceclofenac in carbopol and PEG base and to evaluate it for analgesic and antiinflammatory activity using carrageenan-induced thermal hyperalgesia and paw oedema in rats. Carrageenan administration into the hind paw produced a significant inflammation associated with hyperalgesia as shown by decreased rat paw withdrawal latency in response to a thermal stimulus (47+/-0.5 degrees C) 4 h after carrageenan injection. Topical application of AF1 significantly attenuated the development of hypersensitivity to thermal stimulus as compared to control (P<0.05) and other formulation treated groups (P<0.05). All the AF semisolid formulations, when applied topically 2 h before carrageenan administration, inhibited paw edema in a timedependent manner with maximum percent edema inhibition of 80.33+/-2.52 achieved with AF1 after 5 h of carrageenan administration However, topical application of AF2 markedly prevented the development of edema as compared to other formulation (AF2 and AF3) treated groups (P<0.05). Among all the semisolid formulations, Carbopol gel base was found to be most suitable dermatological base for aceclofenac.