Simultaneous infrared spectrometric determination of lisinopril and hydrochlorothiazide in tablets by chemometric methods

ABSTRACT

A new Fourier transform infrared [FTIR] spectrometric method was developed for assaying hydrochlorothiazide[Hctz] and lisinopril [Lnp] in binary solid pharmaceutical formulations. Initially, the mixture ofhydrochlorothiazide and lisinopril in solid mixtures was analyzed using FT-IR spectrometry in mid-IR range.Simultaneous determination of Hctz and Lnp carried out with inverse least squares [ILS] multivariate calibrationof infrared spectra of binary standards of the drugs. The spectral range of1508-1850 cm[-1] was selected for themeasurement in methanolic solutions. In this method the statistical parameters such as R[2]for Hctz and Lnp were0.9995, 0.9994 and relative standard deviation [RSD] for Hctz and Lnp were 0.71%, 0.63% [n=6], respectively.Detection limits of Lnp and Hctz were obtained 0.75 and 0.90 mg/mL, respectively. USP methods were alsoused for comparing with proposed method, as a reference method. The proposed method was successfullyapplied to the determination of these drugs in laboratory-prepared mixtures and in commercial tablets. Thismethod has suitable accuracy, precision, repeatability; and is comparable with reference standard methods: