Eglal A. Abdelaleem

Quantitative determination of oxybutynin hydrochloride by spectrophotometry, chemometry and HPTLC in presence of its degradation product and additives in different pharmaceutical dosage forms

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.

Linear support vector regression and partial least squares chemometric models for determination of Hydrochlorothiazide and Benazepril hydrochloride in presence of related impurities: a comparative study.

Partial least squares regression (PLSR) and support vector regression (SVR) are two popular chemometric models that are being subjected to a comparative study in the presented work. The comparison shows their characteristics via applying them to analyze Hydrochlorothiazide (HCZ) and Benazepril hydrochloride (BZ) in presence of HCZ impurities; Chlorothiazide (CT) and Salamide (DSA) as a case study. The analysis results prove to be valid for analysis of the two active ingredients in raw materials and pharmaceutical dosage form through handling UV spectral data in range (220-350 nm). For proper analysis a 4 factor 4 level experimental design was established resulting in a training set consisting of 16 mixtures containing different ratios of interfering species. An independent test set consisting of 8 mixtures was used to validate the prediction ability of the suggested models. The results presented indicate the ability of mentioned multivariate calibration models to analyze HCZ and BZ in presence of HCZ impurities CT and DSA with high selectivity and accuracy of mean percentage recoveries of (101.01±0.80) and (100.01±0.87) for HCZ and BZ respectively using PLSR model and of (99.78±0.80) and (99.85±1.08) for HCZ and BZ respectively using SVR model. The analysis results of the dosage form were statistically compared to the reference HPLC method with no significant differences regarding accuracy and precision. SVR model gives more accurate results compared to PLSR model and show high generalization ability, however, PLSR still keeps the advantage of being fast to optimize and implement.

Validated stability indicating RP-HPLC method for determination of paracetamol, methocarbamol and their related substances

Paracetamol (PAR) and methocarbamol (MET) are co-formulated together in Methorelax® tablets which are widely used as a muscle relaxant and in the treatment of muscle-skeletal pain. On the other hand, 4-aminophenol (4-AP) and guaifenesine (GU) have been reported to be related substances and degradation products of PAR and MET, respectively. The target of this work was to develop and validate a simple, sensitive and selective stability indicating RP-HPLC method for the determination of PAR, MET, 4-AP and GU in their bulk powders and laboratory prepared mixtures. Chromatographic separation was achieved within 10 minutes with the required asymmetry, accuracy and precision on ODS column using 0.05 M KH2PO4 buffer : acetonitrile (72.5 : 27.5, v/v, pH = 6) as the mobile phase at a flow rate of 1 mL min−1 with UV detection at 225 nm. The developed method has been validated as per ICH guidelines and the calibration plots were linear over the concentration ranges of 3–20, 4–25, 0.6–8 and 0.6–8 μg mL−1 for PAR, MET, 4-AP and GU, respectively. The method has been successfully applied in the analysis of Methorelax® tablets and good results were obtained. Moreover, its results have been compared to a previously reported RP-HPLC method and no significant difference was found between the two methods.

Stability-Indicating TLC -Densitometric Method for Simultaneous Determination of Paracetamol and Chlorzoxazone and their Toxic Impurities

A highly sensitive, selective and accurate thin-layer chromatographic (TLC)-densitometric method has been developed and validated for the simultaneous determination of paracetamol (PAR) and chlorzoxazone (CZ) and their toxic impurities, 4-amino phenol (4AP) and 2-amino-4-chlorophenol (2ACP), respectively, which are also considered to be the hydrolytic degradation products and related substances of the studied drugs. A developing system consisting of chloroform-methanol-glacial acetic acid (9.5:0.5:0.25, by volume) was found to be sufficient for chromatographic separation among the four studied components using pre-activated silica gel 60 F254 TLC plates with ultraviolet detection at 225 nm. Calibration curves were constructed in the ranges of 0.3-3, 1-10, 0.06-3 and 0.04-3 µg/band for PAR, CZ, 4AP and 2ACP, respectively, using polynomial equations. The developed method was validated according to International Conference on Harmonization guidelines and demonstrated good accuracy and precision. Moreover, the method was successfully applied for the determination of PAR and CZ in different marketed samples and the results were statistically compared to those obtained by the reported reversed-phase high-performance liquid chromatography method using F-test and Students-t test. The low detection and quantitation limits of the developed method make it suitable for quality control and stability studies of PAR and CZ in different pharmaceutical formulations.

Simultaneous determination of methocarbamol and ibuprofen or diclofenac potassium using mean centering of the ratio spectra method

Simultaneous determination of methocarbamol and ibuprofen or diclofenac potassium using mean centering of the ratio spectra method Accurate and sensitive methods were developed for simultaneous determination of methocarbamol and ibuprofen or diclofenac potassium in their binary mixtures, and in the presence of a methocarbamol related substance (guaifenesin) using mean centering of the ratio spectra method. The results obtained were statistically compared with the reported HPLC methods; no significant difference between the proposed methods and the reported methods was found regarding either accuracy or precision. Simultano određivanje metokarbamola i ibuprofena ili diklofenak kalija metodom centriranja srednjih vrijednosti spektralnih omjera (mean centering of the ratio spectra method) U radu su opisane točne i osjetljive metode za simultano određivanje metokarbamola i ibuprofena ili diklofenak kalija u njihovim binarnim smjesama, te u prisutnosti gvajfenezina, supstancije srodne metokarbamolu koristeći metodu centriranja srednjih vrijednosti spektralnih omjera. Dobiveni rezultati su statistički uspoređeni s objavljenim HPLC metodama. Nije pronađena značajna razlika u točnosti i preciznosti između predložene metode i objavljenih metoda.

Novel spectrophotometric determination of flumethasone pivalate and clioquinol in their binary mixture and pharmaceutical formulation.

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.

Simultaneous determination of methocarbamol and its related substance (Guaifenesin) in two ternary mixtures with ibuprofen and diclofenac potassium by HPTLC spectrodensitometric method

Accurate, sensitive, and precise high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the determination of Methocarbamol (ME) and its related substance (guaifenesin (GU)) in two ternary mixtures with ibuprofen (IB) and diclofenac potassium. The method depends on separation and quantification of the studied drugs on TLC silica gel 60 F254 plates using ethyl acetate-acetone-triethylamine-formic acid (62:35:6:0.3, by volume) as the developing system followed by densitometric measurement of the bands at 222 nm for the first mixture containing methocarbmol, IB, and GU and at 278 nm for the second mixture containing methocarbmol, diclofenac potassium, and GU. The proposed methods were successfully applied for the determination of ME, IB, and diclofenac potassium in the presence of ME-related substance (GU) either in bulk powder or in their pharmaceutical formulations.

Simultaneous determination of some antiprotozoal drugs in different combined dosage forms by mean centering of ratio spectra and multivariate calibration with model updating methods

BackgroundMetronidazole (MET) and Diloxanide Furoate (DF), act as antiprotozoal drugs, in their ternary mixtures with Mebeverine HCl (MEH), an effective antispasmodic drug. This work concerns with the development and validation of two simple, specific and cost effective methods mainly for simultaneous determination of the proposed ternary mixture. In addition, the developed multivariate calibration model has been updated to determine Metronidazole benzoate (METB) in its binary mixture with DF in Dimetrol® suspension.ResultsMethod (I) is the mean centering of ratio spectra spectrophotometric method (MCR) that depends on using the mean centered ratio spectra in two successive steps that eliminates the derivative steps and therefore the signal to noise ratio is enhanced. The developed MCR method has been successfully applied for determination of MET, DF and MEH in different laboratory prepared mixtures and in tablets. Method (II) is the partial least square (PLS) multivariate calibration method that has been optimized for determination of MET, DF and MEH in Dimetrol ® tablets and by updating the developed model, it has been successfully used for prediction of binary mixtures of DF and Metronidazole Benzoate ester (METB) in Dimetrol ® suspension with good accuracy and precision without reconstruction of the calibration set.ConclusionThe developed methods have been validated; accuracy, precision and specificity were found to be within the acceptable limits. Moreover results obtained by the suggested methods showed no significant difference when compared with those obtained by reported methods.Graphical Abstract

HPTLC and RP-HPLC methods for simultaneous determination of Paracetamol and Pamabrom in presence of their potential impurities.

Two chromatgraphic methods were developed for determination of Paracetamol (PCM) and Pamabrom (PAM) in presence of P-aminophenol (PAP) and Theophylline (THEO) as potential impurities of both drugs respectively. First method is HPTLC which depends on separation and quantitation of the studied drugs on aluminum plates pre-coated with silica gel 60 F₂₅₄ as a stationary phase using chloroform:methanol:ethyl acetate:glacial acetic acid (8:0.8:0.6:0.2, v/v/v/v) as mobile phase followed by densitometric measurement of the bands at 254 nm. Second method is RP-HPLC which comprises separation of the studied drugs on a Phenomenex C8 column by gradient elution using mobile phase consisting of sodium dihydrogen phosphate buffer (0.05 M): methanol:acetonitrile (85:10:5, v/v/v) at a flow rate of 1 mL/min for first 7.5 min and (70:20:10, v/v/v) at a flow rate of 1.5 mL/min for the next 5 min. The proposed methods were successfully applied for determination of the potential impurities of PCM and PAM after resolving them from the pure drugs. The developed methods have been validated and proved to meet the requirements delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. The validated methods were successfully applied for determination of the studied drugs in their pharmaceutical formulation. The results were statistically compared to those obtained by the reported RP-HPLC method where no significant difference was found; indicating the ability of proposed methods to be used for routine quality control analysis of these drugs.

Development and Validation of HPLC and HPTLC Methods for Determination of Cefoperazone and Its Related Impurities

Validated sensitive and highly selective methods were developed for the quantitative determination of cefoperazone sodium (CEF) in the presence of its reported impurities; 7-aminocephalosporanic acid (7-ACA) and 5-mercapto-1-methyl-tetrazole (5-MER). Method A is high-performance liquid chromatography (HPLC), where the mixture of CEF and the reported impurities; 7-ACA and 5-MER were separated on a C8 column (5 µm ps, 250 mm × 4.6 i.d.) using methanol:0.05 M KH2PO4 buffer (22.5:77.5 v/v, pH 7.5) as a mobile phase. The three components were detected at 254 nm with a concentration range of 10-90 µg mL(-1) and the mean percentage recovery 99.67% (SD 1.465). Method B is high-performance thin layer chromatography (HPTLC), where the mixture of CEF and the reported impurities were separated on silica gel HPTLC F254 plates using (acetone:methanol:ethyl acetate:2% sodium lauryl sulfate:glacial acetic acid) (3:2:3:0.8:0.2, by volume) as a developing system and scanning at 254 nm over a concentration range of 1-10 µg per band with the mean percentage recovery 99.95% (SD 1.335). The proposed methods were statistically compared with a reported HPLC method with no significant difference regarding accuracy and precision; indicating the ability of the proposed methods to be reliable and suitable for routine analysis of drug product. The proposed HPTLC method proved to be more sensitive, while the HPLC gave more reproducible results besides saving time.