Estimation of content of anti-TB drugs supplied at centres of the Revised National TB Control Programme in Tamil Nadu, India.

OBJECTIVE: To determine the content of certain antituberculosis (TB) drugs supplied at TB treatment centres of the Revised National TB Control Programme (RNTCP) in the state of Tamil Nadu, India. METHODS: Eight districts across the state were selected, and the following drugs were collected from five settings (District TB centre, TB unit, designated microscopy centres, DOT providers) in each district: rifampicin (150 and 450 mg), isoniazid (300 mg), pyrazinamide (500 and 750 mg), ethambutol (400 and 600 mg), ethionamide (250 mg), levofloxacin (500 mg) and cycloserine (250 mg). A maximum of 10 tablets/capsules were collected from each setting. The drugs were coded prior to analysis. All drugs were assayed by validated spectrophotometric methods. The acceptable limits for drug content were taken as 90-110% of the stated content. RESULTS: More than 90% of tablets of rifampicin 450 mg, isoniazid 300 mg, pyrazinamide 500 and 750 mg, ethambutol 400 and 600 mg and ethionamide 250 mg were within acceptable limits. Eighty per cent of rifampicin 150 mg, 21% of cycloserine 250 mg and 87% of levofloxacin 500 mg were within acceptable limits. The mean cycloserine content was below the acceptable limit in all districts, the mean drug content being 200 mg (range: 108-245 mg). CONCLUSION: This systematic study showed that the stated drug content of cycloserine was not reached in all districts. Deterioration of cycloserine could be minimised by storing the drug in refrigerators. The geographical location of the districts had no influence on the drug content.

Screening of bulk drug samples and anti-tuberculosis products for the presence of therapeutically less active diasteriomeric (R,S) form of ethambutol dihydrochloride.

BACKGROUND: The present study was carried out to screen various ethambutol dihydrochloride (EB2HCI) bulk drug samples and anti-tuberculosis (anti-TB) products for the presence of less active (R,S)-EB2HCl. METHODOLOGY: Samples of pure EB2HCl were received gratis from various companies and the formulations were procured from local market, and also from a Directly Observed Treatment Short-course (DOTS) centre. Some products available in the institute from Global Drug Facility were also included in the study. In total, 5 API samples and 35 formulations containing EB2HCI were investigated. These were subjected to evaluation for the presence of (R,S)-EB2HCl using a previously published differential scanning calorimetric method. The thermograms were recorded between 25 degrees C and 250 degrees C at a rate of 10 degrees C/min. RESULTS: 1 API sample and 12 formulations were found to contain (R,S)-EB2HCI up to an extent of 30-100%. One of the DOTS centres supply was also found to contain approximately 97% of the less active isomer. CONCLUSION: The presence of therapeutically inactive form of the EB2HCl from 30-100% in approximately 30% of the products in the local market is an alarming finding, which means low quality anti-TB products are in circulation. The same may be contributory to the developing resistance of the drugs against the mycobacterium.