Systemic absorption of diclofenac is generally rapid and directly proportional to the dose. The rate of diclofenac absorption may vary depending on the salt form, pharmaceutical composition or drug delivery system as well as timing of administration in relation to food intake
Approximately 60 % of the intact diclofenac reaches the systemic circulation due to first-pass metabolism. Diclofenac, similar to other acidic NSAIDs, concentrates not only in the systemic circulation, but also in inflamed tissues where the weak acidic environment reduces plasma protein binding. This facilitates diffusion of Diclofenac into the intracellular spaces where its therapeutic effect can take action. (5) In addition because