Muhammad Abdul Qadir, Mahmood Ahmed, Rabia Ikram.
Synthesis, antimicrobial and antifungal possessions of tramadol esters: in vitro studies..
Pak J Pharm Sci Jan ;28(4):1307-10.

Tramadol esters were prepared by refluxing equimolar concentration of tramadol with leucine and asparagine separately with methanol, sulphuric acid and phthalic anhydride for 10 hours and temperature was maintained at 75 degrees C. After refluxing, the colour of sample solutions were changed from colorless to yellow, blank solution was prepared in the same way as the sample solution except the Tramadol. Both the products and blank were neutralized with sodium carbonate and excess of sodium bicarbonate was precipitated as sodium sulphate, which was washed with acetone. The structures of both the products were confirmed with spectral data (FT-IR, 1HNMR and 13CNMR). Antimicrobial and anti-fungal property of derivative of analgesic tramadol drug was tested with one fungus and three sensitive bacteria belonging to both gram positive and gram-negative types. Esterified product of tramadol with leucine and asparagine showed moderate activity against Escherichia coli and Tricophyton rubrum. Both the products showed marked activity against Staphylococcus aureus and found no activity against Salmonella spp.

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