Synthesis and evaluation of some amino acid conjugates of pirprofen

Amino acid conjugates of pirprofen were synthesized by coupling reaction of acid chloride of drug and various amino acid methyl ester hydrochlorides. The synthesized conjugates were characterized by IR, NMR and mass spectral analysis. The hydrolysis study of the conjugates was performed to investigate the kinetic (release rate) behavior of the conjugates and the results showed that the release rate followed first order kinetics. A faster release of the parent drug from the conjugates was observed in 0.05 M phosphate buffer with 80% human plasma owing to presence of amidases. The conjugates were evaluated for analgesic, anti-inflammatory and ulcerogenic activity. Higher anti-inflammatory activity shown by PTME (62.06%) may be due to synergistic effect of amino acid and pirprofen. The conjugates showed comparable analgesic and anti-inflammatory activities to free drug with much reduced ulcerogenicity.