Two smart spectrophotometric methods for simultaneous determination of Lisinopril and Hydrochlorothiazide in binary mixtures

Abstract

Two new, simple, fast and sensitive spectrophotometric methods were developed for analysis of binary mixtures of Lisinopril (LIS) and hydrochlorothiazide (HCT). These methods were absorptivity factor method and ratio subtraction method. In the first method, calculations were made using the absorbance of the mixtures at 211 nm where LIS absorptivity is half HCT absorptivity. On the other hand, the second method was based on obtaining the original spectrum of LIS from the zero order spectrum of the binary mixture then determining the concentration of LIS from its linear regression equation. HCT concentration in both methods was determined from the absorbance at 270 nm where a lack of interference of LIS occurs. The methods were validated according to ICH and applied successfully on different ratios of laboratory mixtures and on pharmaceutical tablets with excellent accuracy and precision.

Mathematical Processing of Absorption as Green Smart Spectrophotometric Methods for Concurrent Assay of Hepatitis C Antiviral Drugs, Sofosbuvir and Simeprevir: Application to Combined Pharmaceutical Dosage Forms and evaluation of the method greenness

“…2.2 Method II: Ratio subtraction method [11][12][13] This method works well for a combination of two drugs A and B with overlapped spectra without the need of an ISP provided that one of them (B) has an extended part in its spectrum of zero order with no interference from drug A. The concentration of drug A can be determined using ratio subtraction where the zero-order spectrum of the mixture is divided by the zero-order spectrum of a certain concentration of B named as the divisor (B').…”

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“…Also, a modern approach of HPLC 25 utilizing a Photo Diode Array detector (HPLC-PDA) was utilized for the simultaneous estimation. The absorptivity factor method and ratio subtraction method are the two new smart spectrophotometric methods 26 used for the estimation of Hydrochlorothiazide. From the exhaustive literature survey, it was found that little work on the HPTLC method has been reported for the simultaneous estimation of Ramipril and Hydrochlorothiazide in the combined formulation.…”

Spectrophotometric and Multivariate Calibration Techniques for Simultaneous Determination of Different Drugs in Pharmaceutical Formulations and Human Urine: Evaluation of Greenness Profile

“…HZ is excreted (>95%) as unchanged drug in urine [23,24]. Different techniques have been reported for HZ quantitation such as HPLC [25][26][27][28], GC [29], spectrophotometry [30,31], and voltammetry [32].…”