Non-aqueous titrimetric assay of doxycycline hyclate in pharmaceutical preparations.

Doxycycline is a member of the tetracycline derivation and has a wide range of antibacterial activity. Two simple, cost-effective, accurate, and precise direct titrimetric methods to the detn. of doxycycline hyclate (DOX) in pharmaceutical prepns. were developed and validated. The methods are based on the titrn. of DOX with 0.01 N acetous perchloric acid in the presence of mercuric acetate in glacial acetic acid using either crystal violet as indicator in visual end point detection (method A) or by combined glass electrode in potentiometric end point detection (method B). The methods were applicable over the range of 4.0 - 40 mg DOX. The validation of the methods yielded good results that included precision (RSD < 3% for intra- and inter-day precision), and accuracy (RE ≤ 2.68%). It was also found that the excipients in the com. tablet prepn. did not interfere with the assay and the results were compared with the official HPLC method. [on SciFinder(R)]