Ibrahim A. Naguib

Development and validation of stability indicating HPLC and HPTLC methods for determination of sulpiride and mebeverine hydrochloride in combination

Validated sensitive and highly selective stability indicating methods are adopted for simultaneous quantitative determination of sulpiride and mebeverine hydrochloride in presence of their reported impurities and hydrolytic degradates whether in pure forms or in pharmaceutical formulation. The first method is High Performance Liquid Chromatography, where the mixture of sulpiride and mebeverine hydrochloride together with the reported interferents plus metopimazine as internal standard are separated on a reversed phase cyano column (5 microm ps, 250 mm x 4.6 id) using acetonitrile: water (70:30 v/v) adjusted to pH = 7 as a mobile phase. The drugs were detected at 221 nm over a concentration range of 5-40 microg ml(-1) and 5-60 microg ml(-1) with mean percentage recoveries 99.75% (S.D. 0.910) and 99.99% (S.D. 0.450) for sulpiride and mebeverine hydrochloride respectively. The second method is High Performance Thin Layer Chromatography, where sulpiride and mebeverine hydrochloride are separated on silica gel HPTLC F(254) plates using absolute ethanol:methylene chloride:triethyl amine (7:3:0.2 by volume) as mobile phase and scanning of the separated bands at 221 nm over a concentration range of 0.4-1.4 and 0.2-1.6 microg band(-1) with mean percentage recoveries 101.01% (S.D. 1.991) and 100.40% (S.D. 1.868) for sulpiride and mebeverine hydrochloride respectively.

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.

Improved partial least squares models for stability‐indicating analysis of mebeverine and sulpiride mixtures in pharmaceutical preparation: A comparative study

Performance of partial least squares regression (PLSR) is enhanced in the presented work by three multivariate models, including weighted regression PLSR (Weighted-PLSR), genetic algorithm PLSR (GA-PLSR), and wavelet transform PLSR (WT-PLSR). The proposed models were applied for the stability-indicating analysis of mixtures of mebeverine hydrochloride (meb) and sulpiride (sul) in the presence of their reported impurities and degradation products. The work introduced in this paper aims to compare these different chemometric methods, showing the underlying algorithm for each and making a comparison of analysis results. For proper analysis, a 6-factor, 5-level experimental design was established resulting in a training set of 25 mixtures containing different ratios of the interfering species. A test set consisting of 5 mixtures was used to validate the prediction ability of the suggested models. Leave one out (LOO) and bootstrap were applied to predict number of PLS components. The GA-PLSR proposed method was successfully applied for the analysis of raw material (test set 101.03% ± 1.068, 101.47% ± 2.721 for meb and sul, respectively) and pharmaceutical tablets containing meb and sul mixtures (10.10% ± 0.566, 98.16% ± 1.081 for meb and sul).

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.

Simultaneous Determination of Hydrochlorothiazide and Benazepril Hydrochloride or Amiloride Hydrochloride in Presence of Hydrochlorothiazide Impurities: Chlorothiazide and Salamide by HPTLC Method

Simple, selective and sensitive high-performance thin layer chromatographic (HPTLC) method has been developed and validated for the simultaneous determination of hydrochlorothiazide (HCZ) in the presence of its impurities (chlorothiazide (CT) and salamide (DSA)), in two quaternary mixtures with benazepril hydrochloride (BZ) or amiloride hydrochloride (AM). The separation was carried out on HPTLC silica gel 60 F254 using ethyl acetate-methanol-glacial acetic acid (85:2:0.3 v/v/v) followed by densitometric measurement of bands at 240 nm for the first mixture containing HCZ, CT, DSA, BZ and by using ethyl acetate-methanol-water-ammonia (90:10:5:3 v/v/v) followed by densitometric measurement at 278 nm for the second mixture containing HCZ, CT, DSA, AM. Calibration curves were constructed in the range of (0.2-1.8 µg/band) and (0.4-2.2 µg/band) with good accuracy for HCZ and BZ, respectively, for the first mixture and in the range of (0.6-1.8 µg/band) and (0.4-2.4 µg/band) with good accuracy for HCZ and AM, respectively, for the second mixture. The developed method was validated according to ICH guidelines and demonstrated good accuracy and precision. Moreover, the methods were successfully applied for the determination of HCZ and BZ and AM in pure form and pharmaceutical dosage forms. The results were statically compared with the reported methods with no significant difference, indicating the ability of the proposed method to be used for routine analysis of drug product.

Quantitative determination of zopiclone and its impurity by four different spectrophotometric methods

Four simple, sensitive and selective spectrophotometric methods are presented for determination of Zopiclone (ZPC) and its impurity, one of its degradation products, namely; 2-amino-5-chloropyridine (ACP). Method A is a dual wavelength spectrophotometry; where two wavelengths (252 and 301 nm for ZPC, and 238 and 261 nm for ACP) were selected for each component in such a way that difference in absorbance is zero for the second one. Method B is isoabsorptive ratio method by combining the isoabsorptive point (259.8 nm) in the ratio spectrum using ACP as a divisor and the ratio difference for a single step determination of both components. Method C is third derivative (D(3)) spectrophotometric method which allows determination of both ZPC at 283.6 nm and ACP at 251.6 nm without interference of each other. Method D is based on measuring the peak amplitude of the first derivative of the ratio spectra (DD(1)) at 263.2 nm for ZPC and 252 nm for ACP. The suggested methods were validated according to ICH guidelines and can be applied for routine analysis in quality control laboratories. Statistical analysis of the results obtained from the proposed methods and those obtained from the reported method has been carried out revealing high accuracy and good precision.

Successive ratio subtraction as a novel manipulation of ratio spectra for quantitative determination of a mixture of furosemide, spironolactone and canrenone

Furosemide and spironolactone are commonly prescribed antihypertensive drugs. Canrenone is the main degradation product and main metabolite of spironolactone. Ratio subtraction and extended ratio subtraction spectrophotometric methods were previously applied for quantitation of only binary mixtures. An extension of the above mentioned methods; successive ratio subtraction, is introduced in the presented work for quantitative determination of ternary mixtures exemplified by furosemide, spironolactone and canrenone. Manipulating the ratio spectra of the ternary mixture allowed their determination at 273.6nm, 285nm and 240nm and in the concentration ranges of (2-16μgmL-1), (4-32μgmL-1) and (1-18μgmL-1) for furosemide, spironolactone and canrenone, respectively. Method specificity was ensured by the application to laboratory prepared mixtures. The introduced method was ensured to be accurate and precise. Validation of the developed method was done with respect to ICH guidelines and its validity was further ensured by the application to the pharmaceutical formulation. Statistical comparison between the obtained results and those obtained from the reported HPLC method was achieved concerning students t-test and F ratio test where no significant difference was observed.

Enhancement of the productivity of the potent bacteriocin avicin A and improvement of its stability using nanotechnology approaches.

Herein, enhancements of the yield and antimicrobial activity duration of the bacteriocin avicin A were accomplished using fractional factorial design (FFD) and layered double hydroxide (LDH) nanoparticles. Firstly, potential factors affecting bacteriocin production were selected for preliminary study. By a 25-1 FFD, high pH was shown to have a positive effect on avicin A yield, while temperature and duration of incubation, as well as peptone nitrogen sources all had negative effects. The highest bacteriocin production and activity (2560 BU/ml) were observed after 30 h of incubation at 30 °C, with pH adjustment at 7, and in the presence of 2 g mannitol as carbon source and 2.2 g peptone as nitrogen source. Secondly, avicin A nanocomposites with different LDH precursors were tested. Only avicin A-ZnAl-CO3 LDH demonstrated a potent antimicrobial activity against Lactobacillus sakei LMGT 2313 that lasted for at least 24 days, as compared to the values of 6 and 15 days observed with the free avicin A that has been stored at room temperature and at 4 °C, respectively. In conclusion, avicin A production and stability can be improved by manipulating the growth conditions and media composition, together with conjugation to LDHs.

Simultaneous Determination of Guaifenesin, Salbutamol Sulfate or Dextromethorphan HBr and Guaifenesin Impurity (Guaiacol) by HPTLC Method

Abstract Simple, selective and sensitive high-performance thin layer chromatographic (HPTLC) method has been developed and validated for the simultaneous determination of Guaifenesin (GUI) and its impurity Guaiacol (GUA), in two ternary mixtures with Salbutamol Sulfate (SAL) or Dextromethorphan HBr (DEX). The separation was carried out on HPTLC silica gel 60 F254 using ethylacetate: hexane: methanol: ammonia (65:35:15:2, by volume) as a developing system followed by densitometric measurement of bands at 227 nm for the first mixture containing GUI, SAL, GUA and by using ethylacetate: hexane: methanol: ammonia (65:35:5:2, by volume) followed by densitometric measurement at 275 nm for the second mixture containing GUI, DEX, GUA. Calibration curves were constructed in the range of (0.2–4 μg/band), (0.2–2 μg/band) and (0.4–1.2 μg/band) with good correlation for GUI, SAL and GUA, respectively, for the first mixture and in the range of (0.4–2 μg/band), (0.2–2 μg/band) and (0.4–1.2 μg/band) with good correlation for GUI, DEX and GUA, respectively, for the second mixture. The developed method was validated according to ICH guidelines and demonstrated good accuracy and precision. The results were statistically compared to the reported methods with no significant difference, indicating the ability of our method to be used for routine analysis of drug product.

Determination of Cefoperazone Sodium in Presence of Related Impurities by Linear Support Vector Regression and Partial Least Squares Chemometric Models.

A comparison between partial least squares regression and support vector regression chemometric models is introduced in this study. The two models are implemented to analyze cefoperazone sodium in presence of its reported impurities, 7-aminocephalosporanic acid and 5-mercapto-1-methyl-tetrazole, in pure powders and in pharmaceutical formulations through processing UV spectroscopic data. For best results, a 3-factor 4-level experimental design was used, resulting in a training set of 16 mixtures containing different ratios of interfering moieties. For method validation, an independent test set consisting of 9 mixtures was used to test predictive ability of established models. The introduced results show the capability of the two proposed models to analyze cefoperazone in presence of its impurities 7-aminocephalosporanic acid and 5-mercapto-1-methyl-tetrazole with high trueness and selectivity (101.87 ± 0.708 and 101.43 ± 0.536 for PLSR and linear SVR, resp.). Analysis results of drug products were statistically compared to a reported HPLC method showing no significant difference in trueness and precision, indicating the capability of the suggested multivariate calibration models to be reliable and adequate for routine quality control analysis of drug product. SVR offers more accurate results with lower prediction error compared to PLSR model; however, PLSR is easy to handle and fast to optimize.