Spectrophotometric quantitative determination of cilazapril and hydrochlorothiazide in tablets by chemometric methods

Four chemometric methods were applied to simultaneous determination of cilazapril and hydrochlorothiazide in tablets. Classical least-square (CLS), inverse least-square (ILS), principal component regression (PCR) and partial least-squares (PLS) methods do not need any priori graphical treatment of the overlapping spectra of two drugs in a mixture. For all chemometric calibrations a concentration set of the random mixture consisting of the two drugs in 0.1 M HCI and methanol (1:1) was prepared. The absorbance data in the UV-Vis spectra were measured for the 15 wavelength points (from 222 to 276 nm) in the spectral region 210-290 nm considering the intervals of deltalambda = 4 nm. The calibration of the investigated methods involves only absorbance and concentration data matrices. The developed calibrations were tested for the synthetic mixtures consisting of two drugs and using the Maple V software the chemometric calculations were performed. The results of the methods were compared each other as well as with HPLC method and a good agreement was found.     

Spectrophotometric determination of benazepril hydrochloride and hydrochlorothiazide in binary mixture using second derivative, second derivative of the ratio spectra and chemometric methods

Different spectrophotometric methods are presented for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical tablets. The first method depends on second derivative (2D) ultraviolet spectrophotometry, with zero crossing and peak to base measurement. The second derivative amplitudes at 214.8 and 227.4 nm were selected for the assay of benazepril hydrochloride and hydrochlorothiazide, respectively. The second method depends on second derivative of the ratio spectra by measurement of the amplitudes at 241.2 and 273.2 nm for benazepril hydrochloride and hydrochlorothiazide, respectively. Chemometric methods, classical least squares and principal component regression, were applied to analyze the mixture. Both the chemometric methods were applied to the zero and first order spectra of the mixture. The proposed methods were successfully applied for the determination of the two drugs in laboratory prepared mixtures and in commercial tablets.     

Simultaneous Estimation of Hydrochlorothiazide,Hydralazine Hydrochloride,and Reserpine Using PCA,NAS, and NAS-PCA

In this study, new and feasible UV-visible spectrophotometric and multivariate spectrophotometric methods were described for the simultaneous determination of hydrochlorothiazide (HCTZ), hydralazine hydrochloride (H.HCl), and reserpine (RES) in combined pharmaceutical tablets. Methanol was used as a solvent for analysis and the whole UV region was scanned from 200–400 nm. The resolution was obtained by using multivariate methods such as the net analyte signal method (NAS), principal component analysis (PCA), and net analyte signal-principal component analysis (NAS-PCA) applied to the UV spectra of the mixture. The results obtained from all of the three methods were compared. NAS-PCA showed a lot of resolved data as compared to NAS and PCA. Thus, the NAS-PCA technique is a combination of NAS and PCA methods which is advantageous to obtain the information from overlapping results.     

Simultaneous resolution of a binary mixture of captopril and hydrochlorothiazide in tablets by bivariate and multivariate spectral calibrations

The multivariate spectral calibration methods, two-linear regression-calibration (bivariate calibration (BC)) and multi-linear regression-calibration (MLRC) are proposed for the simultaneous resolution of a binary mixture of hydrochlorothiazide (HCT) and captopril (CTP), which have closely overlapping spectra. The BC and MLRC calibration algorithms are described for the two-component system, HCT-CTP. Some alternative methods, classical least squares (CLS), inverse least squares (ILS), principal component regression (PCR) and principal least squares (PLS) methods, were also used to determine HCT and CTP in the mixture. Using a synthetic mixture of the two drugs, all the methods were validated and applied to tablets. The BC and MLRC methods which are very rapid, and easy to apply, yet not expensive, are powerful tools with very simple mathematical contents for the quantitative analysis. Data treatment was performed using MAPLE V, EXCEL and SPSS 10.0 Software.     

Simultaneous spectrophotometric determination of diclofenac potassium and methocarbamol in binary mixture using chemometric techniques and artificial neural networks

In this study, the simultaneous determination of diclofenac potassium (DP) and methocarbamol (MT) by chemometric approaches and artificial neural networks using UV spectrophotometry has been reported as a simple alternative to using separate models for each component. Three chemometric techniques-classical least-squares (CLS), principal component regression (PCR), and partial least-squares (PLS)-along with radial basis function-artificial neural network (RBF-ANN) were prepared by using the synthetic mixtures containing the two drugs in methanol. A set of synthetic mixtures of DP and MT was evaluated and the results obtained by the application of these methods were discussed and compared. In CLS, PCR, and PLS, the absorbance data matrix corresponding to the concentration data matrix was obtained by the measurements of absorbances in the range 260-310 nm in the intervals with Δλ = 0.2 nm in their zero-order spectra. Then, calibration or regression was obtained by using the absorbance data matrix and concentration data matrix for the prediction of the unknown concentrations of DP and MT in their mixtures. In RBF-ANN, the input layer consisting of 251 neurons, 9 neurons in the hidden layer, and 2 output neurons were found appropriate for the simultaneous determination of DP and MT. The accuracy and the precision of the four methods have been determined and they have been validated by analyzing synthetic mixtures containing the two drugs. The proposed methods were successfully applied to a pharmaceutical formulation containing the examined drugs.     

Application of LC and HPTLC-densitometry for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide

Two methods are described for the simultaneous determination of benazepril HCl and hydrochlorothiazide in binary mixture. The first method was based on HPTLC separation of the two drugs followed by densitometric measurements of their spots at 238 and 275 nm for benazepril HCl and hydrochlorothiazide, respectively. The separation was carried out on Merck HPTLC aluminum sheets of silica gel 60 F(254,) using ethyl acetate-methanol-chloroform (10:3:2 v/v) as mobile phase. Second order polynomial equation was used for the regression line in the range 2-20 and 2.5-25 microg/spot for benazepril HCl and hydrochlorothiazide, respectively. The second method was based on HPLC separation of the two drugs on reversed phase, ODS column at ambient temperature using a mobile phase consisting of acetonitrile and water (35:65 v/v) and adjusting to pH 3.3 with acetic acid. Quantitation was achieved with UV detection at 240 nm based on peak area with linear calibration curves at concentration ranges 10-60 and 12.5-75 microg ml(-1) for benazepril HCl and hydrochlorothiazide, respectively. The two proposed methods were successfully applied to the determination of both drugs in laboratory prepared mixtures and in commercial tablets. No chromatographic interference from the tablets excipients was found.     

Simultaneous spectrophotometric determination of pseudoephedrine hydrochloride and ibuprofen in a pharmaceutical preparation using ratio spectra derivative spectrophotometry and multivariate calibration techniques

Spectrophotometric methods are described for the simultaneous determination of pseudoephedrine hydrochloride and ibuprofen in their combination. The obtained data were evaluated by using five different methods. In the first method, ratio spectra derivative spectrophotometry, analytical signals were measured at the wavelengths corresponding to either maximums and minimums for both drugs in the first derivative spectra of the ratio spectra obtained by using each other spectra as divisor in their solution in 0.1 M HCl. In the other four spectrophotometric methods using chemometric techniques, classical least-squares, inverse least-squares, principal component regression and partial least-squares (PLS), the concentration data matrix were prepared by using the synthetic mixtures containing these drugs in methanol:0.1 M HCl (3:1). The absorbance data matrix corresponding to the concentration data matrix was obtained by the measurements of absorbances in the range 240-285 nm in the intervals with deltalambda = 2.5 nm at 18 wavelengths in their zero-order spectra, then, calibration or regression was obtained by using the absorbance data matrix and concentration data matrix for the prediction of the unknown concentrations of pseudoephedrine hydrochloride and ibuprofen in their mixture. The procedures did not require any separation step. The linear range was found to be 300-1300 microg/ml for ibuprofen and 100-1300 microg/ml for pseudoephedrine hydrochloride in all five methods. The accuracy and the precision of the methods have been determined and they have been validated by analyzing synthetic mixtures. The five methods were successfully applied to tablets and the results were compared with each other.     

Spectrophotometric and HPTLC-densitometric determination of lisinopril and hydrochlorothiazide in binary mixtures

Different spectrophotometric and HPTLC-densitometric methods are presented for the simultaneous determination of lisinopril and hydrochlorothiazide in pharmaceutical tablets. The spectrophotometric methods include third derivative (³D) ultraviolet spectrophotometry with zero crossing measurement at 217.4 and 233.4 nm, second derivative of the ratio spectra with measurement at 214.3 and 228.0 nm; both classical least squares and principal component regression were applied to the UV absorption and first derivative spectra of the mixture. The HPTLC method was based on separation of both drugs followed by densitometric measurements of their spots at 210 and 275 nm for lisinopril and hydrochlorothiazide, respectively. The separation was carried out on Merck HPTLC aluminum plates of silica gel 60 F₂₅₄, using chloroform–ethylacetate–acetic acid (10:3:2 by vol.) as mobile phase. The linear and second order polynomial were used for the regression equation of lisinopril and hydrochlorothiazide, respectively.     

Dissolution and assaying of multicomponent tablets by chemometric methods using computer-aided spectrophotometer

Dissolution of three component tablets containing paracetamol (APAP), propyphenazone (PP), and caffeine (CAF) was carried out by USP paddle method. Three chemometric methods; inverse least square (ILS), principal component regression (PCR) and partial least squares (PLS) were applied to simultaneous assay of APAP, PP and CAF in tablets. The PCR, PLS and ILS methods were applied to simultaneous dissolution APAP, PP and CAF in tablets using a double beam UV-Vis spectrophotometer without any chemical separation and any graphical treatment of the overlapping spectra of three drugs. Twenty two mixture solutions in different concentrations were prepared in simulated gastric juice (SGJ, USP) for the chemometric calibrations as training set. The absorbance data matrix was obtained by measuring the absorbance at 14 wavelength points (from 222.5 to 292.5 nm) with the intervals of 5 nm (Deltalambda=5 nm) in the spectral region between 200 and 310 nm. Training set and absorbance data were used for the calibrations of chemometric methods. The developed calibrations were tested for the previously prepared solutions of mixture of three drugs for the validation of the assay method. The chemometric calculations were performed by using the 'MAPLE VRSQUO; software. The results of three chemometric methods were statistically compared with each other. These chemometric calibrations were successfully applied to the content uniformity and dissolution of the multicomponent tablets without any separation procedure. The synthetic mixtures of three drugs were used for the validity of the calibrations. Means recoveries (percent) and relative standard deviation of PLS, PCR and ILS methods were found to be 100.1+/-0.6, 101.4+/-1.6 and 100.1+/-0.6 for APAP; 100.9+/-3.2, 102.0+/-3.3 and 100.9+/-3.2 for PP; 99.9+/-3.5, 101.6+/-3.3 and 99.9+/-3.2 for CAF, respectively. Dissolution profiles of three component tablets were performed. More than 95% of drugs were dissolved within 15 min. All of the three-chemometric methods in this study can be satisfactorily used for the quantitative analysis and for dissolutions test of multicomponent dosage form.     

Simultaneous determination of enalapril maleate and hydrochlorothiazide by first-derivative ultraviolet spectrophotometry and high-performance liquid chromatography

Two methods are described for the simultaneous determination of enalapril maleate and hydrochlorothiazide in combined pharmaceutical tablets. The first method depends on first-derivative ultraviolet spectrophotometry, with zero-crossing and peak-to-base measurement methods. The first-derivative amplitudes at 224 and 260 nm were selected for the assay of enalapril maleate and hydrochlorothiazide, respectively. The second method is based on high-performance liquid chromatography on a reversed-phase column using a mobile phase of acetonitrile-water (20:80, v/v) (pH 3.8) with programmable detection at 215 and 275 nm. Both methods showed good linearity, precision and reproducibility. The proposed methods were successfully applied to the determination of these drugs in laboratory-prepared mixtures and in commercial tablets.     

Simultaneous Determination of Valsartan and Hydrochlorothiazide in Tablets by RP-HPLC

A simple, reproducible and efficient reverse phase high performance liquid chromatographic method was developed for simultaneous determination of valsartan and hydrochlorothiazide in tablets. A column having 200 × 4.6 mm i.d. in isocratic mode with mobile phase containing methanol:acetonitrile:water:isopropylalcohol (22:18:68:2; adjusted to pH 8.0 using triethylamine; v/v) was used. The flow rate was 1.0 ml/min and effluent was monitored at 270 nm. The retention time (min) and linearity range (μg/ml) for valsartan and hydrochlorothiazide were (3.42, 8.43) and (5-150, 78-234), respectively. The developed method was found to be accurate, precise and selective for simultaneous determination of valsartan and hydrochlorothiazide in tablets.     

Simultaneous determination of benazepril hydrochloride and hydrochlorothiazide by micro-bore liquid chromatography

A micro-bore liquid chromatographic method was developed for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical dosage forms. The use of a BDS C-18 micro-bore analytical column, results in substantial reduction in solvent consumption and increased sensitivity. The mobile phase consisted of a mixture of 0.025 M sodium dihydrogen phosphate (pH 4.8) and acetonitrile (55:45, v/v), pumped at a flow rate of 0.40 ml min(-1). Detection was set at 250 nm using an ultraviolet detector. Calibration graphs are linear (r better than 0.9991, n = 5), in concentration range 5.0-20.0 microg ml(-1) for benazepril hydrochloride and 6.2-25.0 microg ml(-1) for hydrochlorothiazide. The intra- and interday R.S.D. values were <1.25% (n = 5), while the relative percentage error (Er) was <0.9% (n = 5). The detection limits attained according to IUPAC definition were 0.88 and 0.58 microg ml(-1) for benazepril hydrochloride and hydrochlorothiazide, respectively. The method was applied in the quality control of commercial tablets and content uniformity test and proved to be suitable for rapid and reliable quality control.     

Simultaneous determination of fosinopril and hydrochlorothiazide in pharmaceutical formulations by spectrophotometric methods

Three new spectrophotometric procedures for the simultaneous determination of fosinopril and hydrochlorothiazide are described. The first method, derivative-differential spectrophotometry, comprised of measurement of the difference absorptivities derivatized in the first-order (ΔD₁) of a tablet extract in 0.1 N NaOH relative to that of an equimolar solution in methanol at wavelengths of 227.6 and 276.4 nm, respectively. The second method, depends on the application ratio spectra derivative spectrophotometric method to resolve the interferance due to spectral overlapping. The analytical signals were measured at 237.9, 243.8 nm for fosinopril and 262.4, 269.3 and 278.6 nm for hydrochlorothiazide in the binary mixture, in the first derivative of the ratio spectra of the mixture solutions in methanol. Calibration graphs were established for 4.0–50.0 μg ml⁻¹ fosinopril and 2.0–14.0 μg ml⁻¹ hydrochlorothiazide in binary mixture. The third method, absorbance ratio method, the determination of fosinopril and hydrochlorothiazide was performed by using the absorbances read at 210.0, 219.5 and 271.7 nm in the zero-order spectra of their mixture. The developed methods were compared with absorbance ratio method. Application of the suggested procedures were successfully applied to the determination of this compound in synthetic mixtures and in pharmaceutical preparations, with high percentage of recovery, good accuracy and precision.     

反相高效液相色谱法测定氨氯缬沙噻嗪片中3种组分的溶出度

目的:建立可同时测定氨氯缬沙噻嗪片3种组分溶出度的反相高效液相色谱方法。方法:采用Inertsil ODS-3 C18色谱柱(250 mm×4.6 mm,5μm),以20 mmol.L-1磷酸二氢钾溶液(磷酸调节pH值至3.5)-乙腈(55∶45)为流动相,流速1.0 mL.min-1,检测波长225 nm。结果:氨氯地平、缬沙坦和氢氯噻嗪的线性范围分别为1.3～20.1μg.mL-1(r=0.999 9),39.8～636.8μg.mL-1(r=0.999 9)和3.1～49.4μg.mL-1(r=1.000 0);回收率分别为100.5%,100.6%和100.4%。结论:方法简便快速、重复性好,可用于同时测定氨氯缬沙噻嗪片3种组分的溶出度。     

Two new spectrophotometric approaches to the multicomponent analysis of the acetaminophen and caffeine in tablets by classical least-squares and principal component regression techniques

Classical least-squares (CLS) and principal component regression (PCR) techniques were proposed for the simultaneous analysis of tablets containing acetaminophen and caffeine without using a chemical separation procedure. The chemometric calibrations were prepared by measuring the absorbances values at the 15 wavelengths in the spectral region 215-285 nm and by using a training set of the mixtures of both drugs in 0.1 M HCI. The obtained chemometric calibrations were used for the estimation of acetaminophen and caffeine in samples. The numerical calculations were performed with the 'MAPLE V' software. By applying two techniques to synthetic mixtures, the mean recoveries and the relative standard deviations in the CLS and PCR techniques were found as 99.5 and 1.29, 99.7 and 1.00% for acetaminophen and 99.9 and 1.92, 100.0 and 1.178% for caffeine, respectively. Our results were compared with those obtained previously by one of us considering HPLC method as a reference method. These two methods were successfully applied to a pharmaceutical tablet formulation of two drugs.     

Spectrophotometric simultaneous determination of triamterene and hydrochlorothiazide in triamterene-H tablets by multivariate calibration methods

The multivariate calibration methods of partial least-square regression and principal component regression were applied for the simultaneous spectrophotometry determination of triamterene (TRM) and hydrochlorothiazide (HYD) in their mixtures. The parameters of the chemometric procedure were optimized, and the proposed methods were validated with synthetic samples and applied to analyze these drugs in pharmaceutical products with good accuracy and precision. The results were compared with those given by the British Pharmacopoeia (BP) method. The square of the correlation coefficients (R(2)) for predicted TRM and HYD with the proposed method in a test sample were 0.9994 and 0.9992, respectively. The relative standard deviation for commercial tablets in the proposed method and BP standard method were 0.405 and 2.142%, respectively.     

Three new spectrophotometric methods applied to the simultaneous determination of hydrochlorothiazide and irbesartan

This work involves the simultaneous determination of hydrochlorothiazide and irbesartan in a binary mixture without previous separation by three new analytical methods. The first method, based on compensation technique, is presented for the derivative spectrophotometric determination of binary mixtures with overlapping spectra. By using ratios of the derivative maxima or the derivative minimum, the exact contribution of either component in the binary mixture can be measured and the amounts quantified. The second method uses of the first derivative of the ratio spectra. The ratio spectra were obtained by dividing the absorption spectra of the binary mixture by that of one of the components. The amplitudes in the first derivative of the ratio spectra at 231, 266, 279, 238 and 248 nm were selected to determine hydrochlorothiazide and irbesartan in binary mixtures. The concentration of the other components are then determined from their respective calibration graphs treated similarly. With the third method, the absorbance ratio method, the determination of hydrochlorothiazide and irbesartan was performed using the absorbances read at 272 nm, 241 nm and 263 nm in the zero-order spectra of their mixture. The absorbance ratio was also developed as a comparison method. The three methods are simple, accurate, rapid and require no preliminary separation steps and can, therefore, be used for routine analysis of both drugs in quality control laboratories.     

Analysis of binary mixtures of losartan potassium and hydrochlorothiazide by using high performance liquid chromatography, ratio derivative spectrophotometric and compensation technique

A new simple, precise, rapid and selective reversed-phase high performance liquid chromatographic (HPLC) and two spectrophotometric methods have been described for resolving binary mixture of losartan potassium and hydrochlorothiazide in the pharmaceutical formulations. The first method, is based on HPLC on a reversed-phase column using a mobile phase 0.01 N sodium dihydrogen phosphate:methanol:acetonitrile (8:2:1 v/v/v) (pH 5.5) with detection at 265.0 nm. The second method, is depend on ratio derivative spectrophotometry, the amplitudes in the first derivative of the ratio spectra at 238.360 nm and at 230.423 nm were selected to simultaneously determine losartan potassium and hydrochlorothiazide in the mixture. The third method, based on compensation technique is presented for the derivative spectrophotometric determination of binary mixtures with overlapping spectra. By using ratios of the derivative maxima or the derivative minimum, the exact compensation of either component in the mixture can be achieved, followed by its determination. The accuracy and precision of the methods have been determined and they have been validated by analysing synthetic mixtures containing losartan potassium and hydrochlorothiazide. The methods do not require any separation step. The methods were also applied to the determination of losartan potassium and hydrochlorothiazide in pharmaceutical preparations. The analytical results were quite good in all cases.     

Simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in tablets by second-order derivative spectrophotometry

A second-order derivative spectrophotometric method for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical dosage forms is described. The determination of benazepril hydrochloride in the presence of hydrochlorothiazide was achieved by measuring the second-order derivative signals at 253.6 and 282.6 nm, while the second-order derivative signal at 282.6 nm was measured for the determination of hydrochlorothiazide. The linear dynamic ranges were 14.80-33.80 microg ml(-1) for benazepril hydrochloride and 18.50-42.20 microg ml(-1) for hydrochlorothiazide, the correlation coefficient for the calibration graphs were better than 0.9998, n = 5, the precision (%RSD) was better than 1.43% and the accuracy was satisfactory (Er < 0.99%). The detection limits were found to be 2.46 and 1.57 microg ml(-1) for benazepril hydrochloride and hydrochlorothiazide, respectively. The method was applied in the quality control of commercial tablets and proved to be suitable for rapid and reliable quality control.