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The presence of coloring matters in syrups usually interferes with the spectrophotometric determination of active pharmaceutical ingredients. A novel approach was introduced to eliminate the interference of sunset yellow (coloring matter) in Cyrinol syrup. Smart, simple, accurate, and selective spectrophotometric methods were developed and validated for the simultaneous determination of a ternary mixture of carbinoxamine maleate, pholcodine, and ephedrine hydrochloride in syrup. Four of the applied methods used ratio spectra: successive derivative subtraction coupled with constant multiplication, successive derivative of ratio spectra, ratio subtraction coupled with ratio difference, and ratio spectra continuous wavelet transforms zero-crossing. In addition, a method that was based on the presence of an isosbestic point, the amplitude summation method, was also established. A major advantage of the proposed methods is the simultaneous determination of the mentioned drugs without prior separation steps. These methods were successfully applied for the determination of laboratory-prepared mixtures and a commercial pharmaceutical preparation without interference from additives, thus proving the selectivity of the methods. No significant difference regarding both accuracy and precision was observed upon statistical comparison of the results obtained by the proposed methods with each other and with those of official or reported ones.

A novel approach for the resolution and quantitation of severely overlapped quaternary mixture of carbinoxamine maleate (CAR), pholcodine (PHL), ephedrine hydrochloride (EPH) and sunset yellow (SUN) in syrup was demonstrated utilizing different spectrophotometric assisted multivariate calibration methods. The applied methods have used different processing and pre-processing algorithms. The proposed methods were partial least squares (PLS), concentration residuals augmented classical least squares (CRACLS), and a novel method; continuous wavelet transforms coupled with partial least squares (CWT-PLS). These methods were applied to a training set in the concentration ranges of 40-100 μg/mL, 40-160 μg/mL, 100-500 μg/mL and 8-24 μg/mL for the four components, respectively. The utilized methods have not required any preliminary separation step or chemical pretreatment. The validity of the methods was evaluated by an external validation set. The selectivity of the developed methods was demonstrated by analyzing the drugs in their combined pharmaceutical formulation without any interference from additives. The obtained results were statistically compared with the official and reported methods where no significant difference was observed regarding both accuracy and precision., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A comparative study of smart spectrophotometric techniques for the simultaneous determination of Omeprazole (OMP), Tinidazole (TIN) and Doxycycline (DOX) without prior separation steps is developed. These techniques consist of several consecutive steps utilizing zero/or ratio/or derivative spectra. The proposed techniques adopt nine simple different methods, namely direct spectrophotometry, dual wavelength, first derivative-zero crossing, amplitude factor, spectrum subtraction, ratio subtraction, derivative ratio-zero crossing, constant center, and successive derivative ratio method. The calibration graphs are linear over the concentration range of 1-20 μg/mL, 5-40 μg/mL and 2-30 μg/mL for OMP, TIN and DOX, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and successfully applied to commercial pharmaceutical preparation. The methods that are validated according to the ICH guidelines, accuracy, precision, and repeatability, were found to be within the acceptable limits., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Smart spectrophotometric methods have been applied and validated for the simultaneous determination of a binary mixture of chloramphenicol (CPL) and prednisolone acetate (PA) without preliminary separation. Two novel methods have been developed; the first method depends upon advanced absorbance subtraction (AAS), while the other method relies on advanced amplitude modulation (AAM); in addition to the well established dual wavelength (DW), ratio difference (RD) and constant center coupled with spectrum subtraction (CC-SS) methods. Accuracy, precision and linearity ranges of these methods were determined. Moreover, selectivity was assessed by analyzing synthetic mixtures of both drugs. The proposed methods were successfully applied to the assay of drugs in their pharmaceutical formulations. No interference was observed from common additives and the validity of the methods was tested. The obtained results have been statistically compared to that of official spectrophotometric methods to give a conclusion that there is no significant difference between the proposed methods and the official ones with respect to accuracy and precision., (Copyright © 2015 Elsevier B.V. All rights reserved.)

This work represents a comparative study of two smart spectrophotometric techniques namely; successive resolution and progressive resolution for the simultaneous determination of ternary mixtures of Amlodipine (AML), Hydrochlorothiazide (HCT) and Valsartan (VAL) without prior separation steps. These techniques consist of several consecutive steps utilizing zero and/or ratio and/or derivative spectra. By applying successive spectrum subtraction coupled with constant multiplication method, the proposed drugs were obtained in their zero order absorption spectra and determined at their maxima 237.6 nm, 270.5 nm and 250 nm for AML, HCT and VAL, respectively; while by applying successive derivative subtraction they were obtained in their first derivative spectra and determined at P230.8-246, P261.4-278.2, P233.7-246.8 for AML, HCT and VAL respectively. While in the progressive resolution, the concentrations of the components were determined progressively from the same zero order absorption spectrum using absorbance subtraction coupled with absorptivity factor methods or from the same ratio spectrum using only one divisor via amplitude modulation method can be used for the determination of ternary mixtures using only one divisor where the concentrations of the components are determined progressively. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. Moreover comparative study between spectrum addition technique as a novel enrichment technique and a well established one namely spiking technique was adopted for the analysis of pharmaceutical formulations containing low concentration of AML. The methods were validated as per ICH guidelines where accuracy, precision and specificity were found to be within their acceptable limits. The results obtained from the proposed methods were statistically compared with the reported one where no significant difference was observed., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Four simple, accurate, sensitive and precise spectrophotometric methods were developed and validated for simultaneous determination of Troxerutin (TXN) and Carbazochrome (CZM) in their bulk powders, laboratory prepared mixtures and pharmaceutical dosage forms. Method A is first derivative spectrophotometry (D(1)) where TXN and CZM were determined at 294 and 483.5 nm, respectively. Method B is first derivative of ratio spectra (DD(1)) where the peak amplitude at 248 for TXN and 439 nm for CZM were used for their determination. Method C is ratio subtraction (RS); in which TXN was determined at its λmax (352 nm) in the presence of CZM which was determined by D(1) at 483.5 nm. While, method D is mean centering of the ratio spectra (MCR) in which the mean centered values at 300 nm and 340.0 nm were used for the two drugs in a respective order. The two compounds were simultaneously determined in the concentration ranges of 5.00-50.00 μg mL(-1) and 0.5-10.0 μg mL(-1) for TXN and CZM, respectively. The methods were validated according to the ICH guidelines and the results were statistically compared to the manufacturer's method., (Copyright © 2015 Elsevier B.V. All rights reserved.)

This work is concerned with development and validation of three simple, specific, accurate and precise spectrophotometric methods for determination of flumethasone pivalate (FP) and clioquinol (CL) in their binary mixture and ear drops. Method A is a ratio subtraction spectrophotometric one (RSM). Method B is a ratio difference spectrophotometric one (RDSM), while method C is a mean center spectrophotometric one (MCR). The calibration curves are linear over the concentration range of 3-45 μg/mL for FP, and 2-25 μg/mL for CL. The specificity of the developed methods was assessed by analyzing different laboratory prepared mixtures of the FP and CL. The three methods were validated as per ICH guidelines; accuracy, precision and repeatability are found to be within the acceptable limits., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The resolving power of spectrophotometric assisted mathematical techniques were demonstrated for the simultaneous determination of perindopril arginin (PER) and amlodipine besylate (AML) in presence of their degradation products. The conventional univariate methods include the absorptivity factor method (AFM) and absorption correction method (ACM), which were able to determine the two drugs, simultaneously, but not in the presence of their degradation products. In both methods, amlodipine was determined directly at 360 nm in the concentration range of 8-28 μg mL(-1), on the other hand perindopril was determined by AFM at 222.2 nm and by ACM at 208 nm in the concentration range of 10-70 μg mL(-1). Moreover, the applied multivariate calibration methods were able for the determination of perindopril and amlodipine in presence of their degradation products using concentration residuals augmented classical least squares (CRACLS) and partial least squares (PLS). The proposed multivariate methods were applied to 19 synthetic samples in the concentration ranges of 60-100 μg mL(-1) perindopril and 20-40 μg mL(-1) amlodipine. Commercially available tablet formulations were successfully analysed using the developed methods without interference from other dosage form additives except PLS model, which failed to determine both drugs in their pharmaceutical dosage form., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In the present work, different spectrophotometric methods and one spectrofluorimetric method have been developed and validated for the determination of mosapride citrate in the presence of its acid-induced degradation products. The drug was subjected to stress stability study including acid, alkali, oxidative, photolytic, and thermal stress degradation. The developed spectrophotometric methods included the use of first order derivative ((1)D), derivative of ratio spectra ((1)DD), mean centring of ratio spectra (MC) and H-point standard additions (HPSAM) spectrophotometric methods. For (1)D method, the peaks amplitudes at 282.8 and 319.6 nm were measured, while for (1)DD method those at 308 nm and 323 nm were measured. Mean centring of ratio spectra method used the values at 317 nm for calibration, while for HPSAM the absorbance at 273 and 288.6 nm were used. These methods were successfully applied for determination of mosapride in the concentration range of 5-70 µg.ml(-1). The spectrofluorimetric method was based on measuring the native fluorescence of mosapride in 0.1 M NaOH using λ(excitation) 276 nm and λ(emission) 344 nm and 684 nm with linearity ranges of 50-3000 ng.ml(-1) and 50-9000 ng.ml(-1), respectively. All the developed methods were validated according to the International Conference on Harmonization (ICH) guidelines and were applied for bulk powder and dosage form. The results obtained were statistically compared to each other using one-way ANOVA testing., (Copyright © 2011 John Wiley & Sons, Ltd.)

Hydrochlorothiazide (HCT) and spironolactone (SPR) are mostly co-formulated in antihypertensive formulations. Several methods have been developed and validated for their determination; these methods include spectrophotometric and chemometric-assisted spectrophotometric methods. The developed spectrophotometric methods were isosbestic point (ISO) and ratio subtraction (RS) methods. The absorbance values at 232.4 (lambda(iso1)) and 257.6 nm (lambda(iso2)) were used for determination of the total mixture concentration, while HCT could be directly determined at 317.2 nm (lambda(max)) and by subtraction SPR concentration could be obtained. Also SPR concentration could be calculated by RS method using the absorbance at 243.8 nm (lambda(max)). A wavelength selection method based on genetic algorithm (GAs) was developed and compared to the conventional partial least squares method (PLS). In this method, several parameters were adjusted and the optimum parameter settings were determined using experimental design. The developed chemometric methods were successfully applied for the determination of the HCT and SPR, as well as for determination of their impurities and degradation products. The proposed methods were successfully applied for determination of HCT and SPR in commercial tablets and they were statistically compared to each other and to the reported method. No significant difference was found, providing their accuracy and precision.

Simple, accurate, sensitive and validated UV spectrophotometric, chemometric and HPTLC-densitometric methods were developed for determination of oxybutynin hydrochloride (OX) in presence of its degradation product and additives in its pharmaceutical formulations. Method A is the first derivative of ratio spectra (DD(1)) which allows the determination of OX in presence of its degradate in pure form and tablets by measuring the peaks amplitude at 216 nm. Method B and C are principal component regression (PCR) and partial least-squares (PLS) for determination of OX in presence of its degradate in pure form, tablets and syrup. While, the developed high performance thin layer chromatography HPTLC-densitometric method was based on the separation of OX from its degradation product, methylparaben and propylparaben followed by densitometric measurement at 220 nm which allows the determination of OX in pure form, tablets and syrup. The separation was achieved using HPTLC silica gel F(254) plates and chloroform:methanol:ammonia solution:triethylamine (100:3:0.5:0.2, v/v/v/v) as the developing system. The accuracy, precision and linearity ranges of the developed methods were determined. The results obtained were statistically compared with each other and to that of a reported HPLC method, and there was no significant difference between the proposed methods and the reported method regarding both accuracy and precision., (Copyright (c) 2009 Elsevier B.V. All rights reserved.)

Metronidazole (MZ) is an anti-infective drug used in the treatment of anaerobic bacterial and protozoa infections in humans. It is also used as a veterinary antiparasitic drug. Spiramycin (SP) is a medium-spectrum antibiotic with high effectiveness against Gram-positive bacteria. Three simple, sensitive, selective and precise spectrophotometric methods were developed and validated for the simultaneous determination of MZ and SP in their pure form and in pharmaceutical formulations. In methods A and B, MZ was determined by the application of direct spectrophotometry and by measuring its zero-order (D(0)) absorption spectra at its λ(max) = 311 nm. In method A, SP was determined by the application of first derivative spectrophotometry (D(1)) and by measuring the amplitude at 218.3 nm. In method B, the first derivative of the ratio spectra (DD(1)) was applied, and SP was determined by measuring the peak amplitude at 245.6 nm. Method C entailed mean centering of the ratio spectra (MCR), which allows the determination of both MZ and SP. The methods developed were used for the determination of MZ and SP over a concentration range of 5-25 µg ml(-1). The proposed methods were used to determine both drugs in their pure, powdered forms with mean percentage recoveries of 100.16 ± 0.73 for MZ in methods A and B, 101.10 ± 0.90 in method C, 100.09 ± 0.70, 100.02 ± 0.88 and 100.49 ± 1.26 for SP in methods A, B and C, respectively. The proposed methods were proved using laboratory-prepared mixtures of the two drugs and were successfully applied to the analysis of MZ and SP in tablet formulation without any interference from each other or from the excipients. The results obtained by applying the proposed methods were compared statistically with a reported HPLC method and no significant difference was observed between these methods regarding both accuracy and precision., (© 2010 John Wiley & Sons, Ltd.)

In this work two well known oral hypoglycemic drugs that are administered in combination for patients with type-II diabetes were simultaneously determined. Several spectrophotometric methods were developed and validated for the determination of metformin hydrochloride (MET), pioglitazone hydrochloride (PIO) and pioglitazone acid degradate (PIO Deg). Derivative, ratio derivative, isosbestic and chemometric-assisted spectrophotometric methods were developed. The first derivative (D(1)) method was used for the determination of MET in the range of 5-30 microg x mL(-1) and PIO in the range of 10-90 microg x mL(-1) by measuring the peak amplitude at 247 nm and 280 nm, respectively. The concentration of PIO was calculated directly at 268 nm. The first derivative of ratio spectra (DD(1)) method used the peak amplitudes at 238 nm and 248.6 nm for the determination of MET in the range of 5-30 microg x mL(-1). In the isosbestic point method (ISO), the total mixture concentration was calculated by measuring the absorbance at 254.6 nm. Classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS-2) were used for the quantitative determination of MET, PIO and PIO Deg. The methods developed have the advantage of simultaneous determination of the cited components without any pre-treatment. Resolution and quantitative determination of PIO degradate with a minimum concentration of 3 microg x mL(-1) in drug samples was done. The proposed methods were successfully used to determine each drug and the acid degradate in a laboratory-prepared mixture and pharmaceutical preparations. The results were statistically compared using one-way analysis of variance (ANOVA). The methods developed were satisfactorily applied to the analysis of the two drugs in pharmaceutical formulations.

Two different methods manipulating spectrophotometric data have been developed, validated and compared. One is capable of removing the signal of any interfering components at the selected wavelength of the component of interest (univariate). The other includes more variables and extracts maximum information to determine the component of interest in the presence of other components (multivariate). The applied methods are smart, simple, accurate, sensitive, precise and capable of determination of spectrally overlapped antihypertensives; hydrochlorothiazide (HCT), irbesartan (IRB) and candesartan (CAN). Mean centering of ratio spectra (MCR) and concentration residual augmented classical least-squares method (CRACLS) were developed and their efficiency was compared. CRACLS is a simple method that is capable of extracting the pure spectral profiles of each component in a mixture. Correlation was calculated between the estimated and pure spectra and was found to be 0.9998, 0.9987 and 0.9992 for HCT, IRB and CAN, respectively. The methods were successfully determined the three components in bulk powder, laboratory-prepared mixtures, and combined dosage forms. The results obtained were compared statistically with each other and to those of the official methods. [ABSTRACT FROM AUTHOR]

Smart and novel spectrophotometric and chemometric methods have been developed and validated for the simultaneous determination of a binary mixture of chloramphenicol (CPL) and dexamethasone sodium phosphate (DSP) in presence of interfering substances without prior separation. The first method depends upon derivative subtraction coupled with constant multiplication. The second one is ratio difference method at optimum wavelengths which were selected after applying derivative transformation method via multiplying by a decoding spectrum in order to cancel the contribution of non labeled interfering substances. The third method relies on partial least squares with regression model updating. They are so simple that they do not require any preliminary separation steps. Accuracy, precision and linearity ranges of these methods were determined. Moreover, specificity was assessed by analyzing synthetic mixtures of both drugs. The proposed methods were successfully applied for analysis of both drugs in their pharmaceutical formulation. The obtained results have been statistically compared to that of an official spectrophotometric method to give a conclusion that there is no significant difference between the proposed methods and the official ones with respect to accuracy and precision. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two novel methods namely; absorbance subtraction (AS) and amplitude modulation (AM) methods were developed. [•] Six recently well established spectrophotometric methods (SRS, RD, RS, EXRS, CM and MCR) were applied. [•] The proposed methods are very simple, accurate, precise. [•] They do not require any sophisticated apparatus or computer programs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Omarigliptin was liable to hydrolytic and oxidative degradations. • Novel stability indicating spectrophotometric methods were developed. • Four univariate and two multivariate approaches were adopted. • Validation was conducted as per ICH guidelines. Six selective spectrophotometric techniques, four univariate and two multivariate ones were developed for the determination of the antidiabetic drug omarigliptin (OMR) along with its hydrolytic and oxidative degradation products. The proposed univariate spectrophotometric methods were ratio subtraction, first derivative, derivative ratio and ratio difference. Linearities were constructed in the range of 10.0–180.0 μg mL−1 for both OMR & its hydrolytic degradation product and 10.0–110.0 μg mL−1 for the oxidative degradation one. On the other hand, partial least squares and artificial neural networks were the chosen multivariate approaches. Their linearity ranges were 20.0–60.0 μg mL−1 for OMR and 10.0–30.0 μg mL−1 for the two degradation products. All the methods were validated, effectively applied for quantification of the intact drug in its tablet formulation and favorably compared to the reported one. [ABSTRACT FROM AUTHOR]

Abstract: Four accurate and sensitive methods were developed and validated for determination of naphazoline hydrochloride (NAP) and chlorpheniramine maleate (CLO) in the presence of naphazoline hydrochloride alkaline degradation product (NAP Deg). The first method is a spectrophotometric one , where NAP was determined by the fourth derivative (D4) spectrophotometric method by measuring the peak amplitude at 302nm, while CLO was determined by the second derivative of the ratio spectra (DD2) spectrophotometric method at 276.4nm. The second method is a chemometric-assisted spectrophotometric method in which partial least squares (PLS-1) and partial component regression (PCR) were used for the determination of NAP, CLO and NAP Deg using the information contained in their absorption spectra of ternary mixture. The third method is a TLC-densitometric one where NAP, CLO and NAP Deg were separated using HPTLC silica gel F254 plates using ethyl acetate:methanol:ammonia: (8:2:0.5, by volume) as the developing system followed by densitometric measurement at 245nm. The fourth method is HPLC method where NAP, CLO and NAP Deg were separated using ODS C18 column and a mobile phase consisting of 0.1M KH2PO4 (pH=7):methanol (55:45 v/v) delivered at 1.5mLmin−1 followed by UV detection at 265nm. The proposed methods have been successfully applied to the analysis of NAP and CLO in pharmaceutical formulations without interference from the dosage form additives and the results were statistically compared with a reported method. [Copyright &y& Elsevier]

In this work three different spectrophotometric methods were established for the determination of cimetidine (I), ranitidine hydrochloride (II) and famotidine (III) The first one is a colorimetric method, it was applied for the determination of the three drugs by using sodium nitroprusside as a color reagent to produce a red colored complexes. In this method, the zero order spectrum 0D was used for the determination of drug (III) at λ=500 nm while the first derivative spectra 1D were used for the determination of drug (I) and (II) at their corresponding wave lengths 523 and 510 nm and Δλ=4 nm. The method can be considered as a stability indicating method for the determination of the three drugs in the presence of their induced hydrogen peroxide oxidative degradates. Beer's law was obeyed in the concentration range of 25–150 µg·mL-1 for (I) and 50–500 µg·mL-1 for (II) and (III) with mean percentage recoveries of 100.27±0.697, 99.79±0.465 and 99.15±0.687, respectively. The second method is a simple colorimetric method, it was applied for the determination of drug (III). Where, 3-Methyl-2-benzo-thiazolinone hydrazone (MBTH) was used as a color reagent. It reacts with the drug to produce a bluish violet color, having two maxima at 536 and 620 nm. The percentage recoveries were 99.73±1.048 and 99.94±0.887, respectively within the concentration range of 20–120 µg·mL-1. The third one is a spectrophotometric method via a complex formation reaction by using cobalt II. A colorless complex was developed having λmax at 319 nm with a ratio of 1:1 and a stability constant logarithm of 5.49. The percentage recovery was 99.84±0.858 within a concentration range of 10–60 µg·mL-1. The statistical comparison with the BP official methods and the assay validation for the three proposed methods has been applied. The results obtained showed that they could be used for... [ABSTRACT FROM AUTHOR]

Simple, sensitive and rapid spectrophotometric techniques have been established for the determination of cimetidine (I), famotidine (II) and ranitidine hydrochloride (III) in presence of their S-oxide derivatives in both raw materials and in pharmaceutical formulations. Hydrogen peroxide was used to enhance the formation of S-oxide compounds (oxidative derivatives). The first derivative of the ratio spectra (@DD) technique has been applied for the determination of (I) and (II). While, direct zero order ([sup 0]D), first derivative (@D) and the second derivative of the ratio spectra (2DD) have been carried out for the determination of drug (III). Linear calibration curves were obtained for determination of (I) and (II) by applying ¹DD at 220 and 230 nm in the concentration range of 2-20 and 4-40 µg mL[sup -1] with the mean percentage recoveries of 99.88 ± 0.943 (n = 10) and 99.88 ± 0.824% (n = 10) for (I) and (II), respectively. While for (III) linear calibration curves were obtained by applying [sup 0]D, ¹D and ²DD at 313, 334 and 255nm, respectively. The concentration range was 2-20 µg mL[sup -1] with the corresponding mean percentage recoveries of 100.13±0.464, 100.01±0.428 and 99.94± 0.439 for (I), (II) and (III), respectively. The results obtained by the proposed methods were statistically analyzed and compared with those obtained by the official BP methods. [ABSTRACT FROM AUTHOR]

Paracetamol (PAR), Pseudoephedrine hydrochloride (PSE) and cetirizine dihydrochloride (CET) is a ternary mixture that composes tablets which are popular for the relief of flu in Egypt. The spectra of the drugs were overlapped and no spectrophotometric methods were reported to resolve the mixture. This research proposes four spectrophotometric methods that are efficient and require water only as a solvent. The first method was ratio subtraction-ratio difference method (RSDM) where PAR was initially removed from the mixture by ratio subtraction and determined at 292.4 nm, then PSE and CET were quantified by subtracting the amplitudes of their ratio spectra between 257.0 and 230.0 nm for PSE and between 228.0 and 257.0 nm for CET. The second method was derivative ratio spectra—zero crossing (DRZC) which was based on determining both PSE and CET from the zero-crossing points of the first and third derivative of their ratio spectra at 252.0 and 237.0 nm, respectively while PAR was determined using its first derivative at 292.4 nm. Moreover, the ternary mixture was resolved using successive derivative ratio (SDR) method where PAR, PSE and CET were determined at 310.2, 257.0 and 242.4 nm, respectively. The fourth proposed method was pure component contribution algorithm (PCCA) which was applied to quantify the drugs at their λmax. Recovery percentages for RSDM were 100.7 ± 1.890, 99.69 ± 0.8400 and 99.38 ± 1.550; DRZC were 101.8 ± 0.8600, 99.04 ± 1.200 and 98.95 ± 1.300; SDR were 101.9 ± 1.060, 99.59 ± 1.010 and 100.2 ± 0.6300; PCCA were 101.6 ± 1.240, 99.10 ± 0.5400 and 100.4 ± 1.800 for PAR, PSE and BRM; respectively. The suggested methods were effectively applied to analyze laboratory prepared mixtures and their combined dosage form. [ABSTRACT FROM AUTHOR]

[Display omitted] • The developed methods are simple, accurate, and precise spectrophotometric methods. • Four methods were used simultaneous determination of glimepiride and pioglitazone hydrochloride. • The methods were successfully applied for the determination of glimepiride and pioglitazone hydrochloride in pure powder and dosage form. • The results obtained were compared statistically with the official one. Simple, accurate, and precise four spectrophotometric methods were developed and validated for simultaneous determination of glimepiride and pioglitazone hydrochloride in their pharmaceutical formulation. The first spectrophotometric method was the dual-wavelength which determined glimepiride at 219.0 and 228.0 nm and pioglitazone hydrochloride at 268.0 nm. The second one is the first derivative of ratio spectra (DD1) spectrophotometry in which the peak amplitudes were used at 238.0 nm and 268.0 nm for glimepiride and pioglitazone hydrochloride, respectively. The third method is ratio subtraction in which glimepiride was determined at 228.0 nm in the presence of pioglitazone hydrochloride which was determined by extended ratio subtraction at 268.0 nm. The fourth method was the ratio difference to determine glimepiride and pioglitazone hydrochloride. Beer's law was confirmed in the concentration range 2.50–15.00 µg mL-1, and 10.00–50.00 µg mL-1 for glimepiride and pioglitazone respectively for the four methods. The proposed methods were used to determine both drugs in their pure powdered form with mean percentage recoveries of 99.91 ± 1.117% for glimepiride and 99.76 ± 0.911% for pioglitazone hydrochloride in method (A). In method (B), the mean percentage recoveries were 100.12 ± 0.89% for glimepiride and 100.02 ± 1.06% for pioglitazone hydrochloride. In method (C) glimepiride was 100.01 ± 0.592% and 99.85 ± 0.845% for pioglitazone hydrochloride by extended ratio subtraction. And finally, in method (D) the mean percentage recoveries were 100.66 ± 0.670% for glimepiride and 99.92 ± 0.988% for pioglitazone hydrochloride. The developed methods were successfully applied for the determination of glimepiride and pioglitazone hydrochloride in pure powder and dosage form. The suggested methods were also used to determine both compounds in laboratory-prepared mixtures. The accuracy, precision, and linearity ranges of the developed methods were determined. The results obtained were compared statistically with the official method, and there was no significant difference between the proposed methods and the official method for accuracy and precision. [ABSTRACT FROM AUTHOR]