Hydrochlorothiazide liquid chromatographic methods

Extensive literature reviews (554, 555) have indicated that almost all reported analytical methods for the analysis of diuretics employ liquid chromatography. Most of these methods are limited, however, to assaying diuretics in urine and plasma. With the exception of a liquid chromatographic method for the determination of furosemide, another one for chlormethiazide, and a third method for chlorothiazide and hydrochlorothiazide residues in bovine milk, no chromato-... 

On the basis of the above observations, a common extraction and cleanup procedure was developed and applied in two recently reported liquid chromatographic methods for the determination of either chlorothiazide and hydrochlorothiazide (558) or chlormethiazide (559) in bovine milk. Both of these methods involve a defatting step by milk centrifugation. Tire defatted milk (4.75 ml) is mixed with 2 ml 5% lead acetate solution and extiacied with 9 ml acetonitrile. Following centrifugation, the supernatant is extracted with 25 ml water-saturated... 

Panderi and Parissi-Poulou developed a microbore liquid chromatographic method for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical dosage forms [30]. The use of a BDS C-18 microbore analytical column was found to result in substantial reduction in solvent consumption and in increased sensitivity. The mobile phase consisted of a mixture of 25 mM sodium dihydrogen phosphate buffer (pH 4.8) and acetonitrile (11 9 v/v), pumped at a flow rate of 0.4 mL/min. Detection was effected at 250 nm using an ultraviolet absorbance detector. The intra- and inter-day relative standard deviation values were less than 1.25% (n = 5), while the relative percentage error was less than 0.9% (n = 5). The detection limits obtained according to the IUPAC definition were 0.88 and 0.58 pg/mL for benazepril hydrochloride and hydrochlorothiazide, respectively. The method was applied to the quality control of commercial tablets and content uniformity test, and proved to be suitable for rapid and reliable analysis. 

Manna et al. described a rapid and accurate reversed-phase ion-paring liquid chromatographic method, with ultraviolet detection, for the simultaneous assay of benazepril hydrochloride, fosinopril sodium, ramipril and hydrochlorothiazide [32], The separation was achieved on a LC-8 (12.5 cm x 4 mm, 5 pm particle size) column. The mobile phase consisted of 20 mM sodium heptansulfonate (pH 2.5) and methanol (8 17 v/v). Validation of the method showed it to be precise, accurate, and linear over the concentration range of analysis, with a limit of detection of 2 ng for benazepril. The method was applied to the analysis of three different binary commercial formulations. 

Cakir et al. reported the use of a high performance liquid chromatographic method and a spectrophotometric method for the analysis of benazepril hydrochloride and hydrochlorothiazide [39]. 

Azumaya, C.T. Sensitive liquid chromatographic method for the determination of hydrochlorothiazide in human plasma. J.Chromatogr., 1990, 532, 168—174... 

A procedure for the determination of diuretics of different therapeutical character high (bumetanide, ethacrynic acid, furosemide), intermediate (bendroflumethiazide, chlorthalidone, hydrochlorothiazide, xipamide) and low (acetazolamide, amiloride, spironolactone, triamterene) efficacy diuretics, and the uricosuric agent probenecid, in urine samples, illustrates a method development implying the control of pH, surfactant and modifier [23]. The greatest analytical problems in the detection of these compounds are basically their wide variety of chemical structures, functional groups and protonation constants. This implies the use of several experimental conditions for their analysis with conventional aqueous-organic mobile phases and laborious liquid-liquid or solid-liquid extraction prior to chromatographic separation. In contrast, the same micellar eluent can produce a satisfactory separation after direct injection. 

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