Antibiotic sensitivity study of marketed preparations of Doxycycline HCl against different microorganisms

Abstract

Doxycycline is a semisynthetic broad-spectrum tetracycline antibiotic, active against a wide range of gram-positive and gram-negative organism. It is used to treat infection caused by susceptible bacteria. This study was employed to evaluate the microbial sensitivity pattern of two brands of doxycycline hydrochloride (Doxicap®, Impedox®) at different concentrations (200mg, 250mg, 300mg, 350mg and 400mg) against four microorganisms (Staphylococcus aureas, Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae). For Staphylococcus aureas, Streptococcus pneumoniae, Escherichia coli three concentrations were tested which were 300mg, 350mg and 400mg and for Haemophilus influenzae also three concentrations were tested which were 200mg, 250mg, 300mg. Kirby-Bauer disc diffusion method was used to investigate whether there is any significant difference with standard or not. Antimicrobial resistance is a very significant public health issue. The global presence of antimicrobial resistance is threatening the continue effectiveness of many current medications due to poor quality drug, counterfeit medications etc. The present study showed that, the amount of crude Doxycycline present in the two brands was effective in terms of purity, but whether the drug is therapeutically active or not can be determine by performing the quality control tests.