Bioadhesive formulations have a wide scope of application for both systemic and local effects of the drug. The oral transmucosal drug delivery bypasses liver and avoids pre-systemic elimination. The strategies to overcome such obstacles include the employment of new materials that, possibly, combine mucoadhesive and penetration enhancer properties and the design of novel drug delivery systems which, besides improving patient compliance, favor a more intimate contact of the drug with the absorption mucosa. Cellulose derivatives like HPMC is having good mucoadhesive property however it's potential can be increased by inclusion of plant derived gum like gum karaya. Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) with pain relieving properties. It is used to treat many painful conditions, inflammation, swelling, and /or stiffness caused by several conditions and acute postoperative pain. One form of diclofenac, the potassium salt, is more effective at the same dose than the other form of diclofenac, the sodium salt. In view of first pass effect it has been selected as model drug for the study.