Synthesis, biological activities, and pharmacokinetics studies of a mutual prodrug of aceclofenac and paracetamol

An ester-based mutual prodrug (aceclofenac–paracetamol; AC-PR) was synthesized (one-pot method) with an aim of improving the therapeutic index through prevention of gastrointestinal irritation and bleeding that is associated with aceclofenac. The release of aceclofenac and paracetamol from the ester prodrug (AC-PR) was studied by reverse phase HPLC in hydrochloric acid buffer (pH 1.2), phosphate buffer (pH 7.4), 80 % v/v human plasma, 10 % w/v rat intestinal homogenate and 10 % w/v rat liver homogenate (pH 7.4). The prodrug showed negligible hydrolysis at pH 1.2 as compared to pH 7.4, suggesting that very less of the prodrug would hydrolyze in stomach, but would release the parent drugs at pH 7.4 in adequate amounts. The prodrug showed enhanced anti-inflammatory activity and significant protection against acetic acid-induced writhings (analgesic activity) as compared to that of aceclofenac. Further, the prodrug produced reduced number of ulcers as compared to that of the parent drug. These results suggest that the synthesized mutual prodrug (AC-PR) is better in terms of activity and GIT toxicity than the parent drug.