Pyrazinamide hydrochloride

QHgN2 95-54-5) see Benperidol Droperidol Mibefradil hydrochloride Pyrazinamide Tiabendazole Tibezonium iodide... 

Various antituberculosis agents ethambutol hydrochloride pyrazinamide... 

Most pharmacopoeias specify that ethambutol hydrochloride contains not less than 98.0% and not more than 100.5% of C10H24N2O2 2HCI, calculated on the dried basis. Pharmaceutical products such as tablets must contain not less than 95.0% and not more than 105.0% of the labeled amount.As for pyrazinamide, the main pharmacopoeia assay method for ethambutol is a titration method. However, an HPLC method is used for the assay of ethambutol HCl in tablets.This method requires that a liquid chromatograph equipped with a 200-nm detector and a 4.6 mm X 15 cm base-deactivated column that contains 5 p,m porous silica particles, 3-10 p,m in diameter, with chemically bonded nitrile groups (CN, LIO) is used. The mobile phase is a mixture of 1.0 ml of triethylamine and 1 L of water, adjusted with phosphoric acid to a pH of 7.0. The flow rate is about 1.0 ml/min. Separately inject equal volumes (about 50 p.1) of standard preparations and the assay preparations into the chromatograph, record the chromatograms, and measure the responses for the major peaks and calculate the quantity, in mg, of ethambutol hydrochloride present in the tablets from the peak responses obtained from the assay preparation and the standard preparation, respectively. The tailing factor must not be more than 2.0, and the relative standard deviation for replicate injections not more than 2.0%. 

The international pharmacopoeia recently also pub-hshed an HPLC assay for ethambutol combined with iso-niazid and pyrazinamide using a stainless steel Cjg column (15 cm X 4.6 mm). The mobile phase for this method is a solution prepared as follows dissolve 50 g ammonium acetate and 0.2 g copper(ll) acetate in 1000 ml of water and adjusted to pH 5.0 with glacial acetic acid. 940 ml of this solution is mixed with 60 ml methanol. The HPLC is operated at a flow rate of 2.0 ml/min. The detector is an ultraviolet spectrophotometer set at a wavelength of about 270 nm and 20 jl1 of the solutions are injected. The assay is not valid unless the resolution between the isoniazid peak (the peak with the shorter retention time) and the ethambutol hydrochloride peak is at least 10 (see Fig. 2) and the resolution between the isoniazid and pyrazinamide peaks is at least 2. The relative standard deviation for the peak areas of isoniazid, pyrazinamide, and ethambutol hydrochloride, eluting in this order, is less than 2.0%. 

WHO. International pharmacopoeia monograph on rifampicin, isoniazid, pyrazinamide and ethambutol hydrochloride tablets. Working document QAS/04.097 rev Oct 05. Quality Assurance Safety Medicines (QSM), Department of Essential Drugs and Medicines Policy (EDM). WHO Geneva, October, 2005. 

Allen, L.V. Jr. Erickson,M.A. III. Stability of bethanechol chloride, pyrazinamide, quinidine sulfate, rifampin, and tetracycline hydrochloride in extemporaneously compounded oral hquids, Am.J.Health Syst.Pharm., 1998, 55, 1804-1809. 

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