African Journal of Pharmacy and Pharmacology Vol. 5(3), pp. 298-305, March 2011 Available online http://www.academicjournals.org/ajpp DOI: 10.5897/AJPP10.083 ISSN 1996-0816 ©2011 Academic Journals Full Length Research Paper Stability-indicating (liquid chromatographic) LC method for the determination of rifabutin in bulk drug and in pharmaceutical dosage form Jaiprakash N. Sangshetti, Sachin Hingankar, Amol Waghule and Devanand B. Shinde* Department of Chemical Technology, Dr. Babasaheb Ambedkar Marathwada University, India. Accepted 15 March, 2011 A novel stability-indicating LC assay method was developed and validated for quantitative determination of Rifabutin in bulk drugs and in pharmaceutical dosage form in the presence of degradation products generated from forced degradation studies. An isocratic, reversed phase LC method was developed to separate the drug from the degradation products, using an Ace5-C18 (250 x 4.6 mm, 5 μm) column, and 50 mM ammonium acetate (pH-4 by acetic acid) and acetonitrile (50:50v/v) as a mobile phase. The detection was carried out at the wavelength of 275 nm. The Rifabutin was subjected to stress conditions of hydrolysis (acid, base), oxidation, photolysis and thermal degradation. Degradation was observed for Rifabutin hydrolysis (acid, base), oxidation and photolysis conditions attempted. There is no degradation in thermal condition. The degradation products were well resolved from the main peak. The percentage recovery of Rifabutin ranged from (99.42 to 100.27%) in pharmaceutical dosage form. The developed method was validated with respect to linearity, accuracy (recovery), precision, specificity and robustness. The forced degradation studies prove the stability- indicating power of the method. Key words: Rifabutin, column liquid chromatography, stability indicating method, validation. INTRODUCTION Rifabutin is chemically known as (Figure 1; 4-deoxo-3, 4- [2-spiro-(N-iso- butyl - 4 - piperidyl) - 2, 5 - dihydro - 1H - imidazo] - rifamycin-S), a semisynthetic derivative of rifampicin S, that has shown broad-spectrum antibacterial activity against Gram-positive and Gram-negative organisms, including mycobacteria. Rifabutin was found to have activity against Mycobacterium avium- intracellular isolated from patients with AIDS (Heifets, 1987) has been approved for prophylaxis of combination therapy containing rifampin.Disseminated Mycobacterium avium complex (MAC) in patients infected with human immunodeficiency virus (HIV). Prophylactic treatment with rifabutin was shown to decrease the incidence of MAC by approximately 50% in AIDS patients enrolled in two randomized, placebo - controlled clinical trials *Corresponding author. E-mail: dbsjaiprakash05@rediffmail. com. (Nightingal, 1993). Rifabutin (Rfb) is a bactericidal antibiotic drug primarily used in the treatment of tuberculosis. Its effect is based on blocking the DNA- dependent RNA-polymerase of the bacteria. It is effective against Gram-positive and some Gram-negative bacteria, but also against the highly resistant Mycobacteria, e.g. Mycobacterium tuberculosis, Mycobacterium leprae and Mycobacterium avium intracellulare. A recent literature survey revealed that few methods were available for the determination of rifabutin in bio- logical samples, which involved high performance liquid chromatography (HPLC) with UV detection (Lau, 1996; Gatti, 1999). According to current good manufacturing practices, all drugs must be tested with a stability- indicating assay method before release. Literature survey reveals that there is no stability-indicating LC assay method for determination of Rifabutin in bulk drug and pharmaceutical dosage form. In the present research article, we report the development and validation of a stability-indicating LC method for the determination of