Maissa Y. Salem

Three different spectrophotometric methods manipulating ratio spectra for determination of binary mixture of Amlodipine and Atorvastatin.

Three simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra are developed for the simultaneous determination of Amlodipine besylate (AM) and Atorvastatin calcium (AT) in tablet dosage forms. The first method is first derivative of the ratio spectra ((1)DD), the second is ratio subtraction and the third is the method of mean centering of ratio spectra. The calibration curve is linear over the concentration range of 3-40 and 8-32 μg/ml for AM and AT, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. Standard deviation is <1.5 in the assay of raw materials and tablets. Methods are validated as per ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit.

Removal of cationic and anionic dyes from aqueous solution with magnetite/pectin and magnetite/silica/pectin hybrid nanocomposites: kinetic, isotherm and mechanism analysis

Novel adsorbents, magnetite nanoparticles modified with pectin shell and silica/pectin double shell, were fabricated and tested for single dye and dye mixture adsorption from water samples. Cationic dyes methylene blue (MB) and crystal violet (CV) and anionic dyes methyl orange (MO) and Eriochrome black T (EBT) were employed to assess dye removal efficiency. The influence of pH, amount of adsorbent, initial dye concentration and contact time was investigated. Results indicated that the optimum pH for removing cationic dyes was 8.0 and 2.0 for anionic dyes. The kinetic studies showed rapid sorption dynamics following a second-order kinetic model. Dye adsorption equilibrium data were fitted well to the Sips isotherm for cationic and anionic dyes. The maximum monolayer capacity, (qmax) for MB, CV, EBT and MO was calculated from Sips as 197.18, 180.29, 65.35 and 26.75 mg g−1 respectively for magnetite/silica/pectin NPs and 168.72, 140.49, 72.35 and 27.22 mg g−1 respectively for magnetite/pectin nanoparticles. For dye mixture adsorption, a new HPLC assay was proposed for quantitation of dyes in treated samples. The results came in accordance with that of single dye adsorption where the magnetite/pectin NPs showed preferred adsorption to anionic dyes while the magnetite/silica/pectin NPs had more affinity to cationic dyes. Thus, our proposed NPs can be used as cheap and efficient adsorbents for removal of cationic and anionic dyes from aqueous solutions.

Three different methods for determination of binary mixture of Amlodipine and Atorvastatin using dual wavelength spectrophotometry.

Three simple, specific, accurate and precise spectrophotometric methods depending on the proper selection of two wavelengths are developed for the simultaneous determination of Amlodipine besylate (AML) and Atorvastatin calcium (ATV) in tablet dosage forms. The first method is the new Ratio Difference method, the second method is the Bivariate method and the third one is the Absorbance Ratio method. The calibration curve is linear over the concentration range of 4-40 and 8-32 μg/mL for AML and ATV, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. Methods are validated according to the ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit. The mathematical explanation of the procedures is illustrated.

Quality in the pharmaceutical industry - A literature review

Objectives The aim of this study is to:a. Highlight the most important guidelines and practices of quality in the pharmaceutical industry.b. Organize such guidelines and practices to create a guide to pave the way for other researchers who would like to dig deeper into these guidelines and practices. Design A review was conducted of 102 publications; 56 publications were concerned with the pharmaceutical quality directly while 46 publications were concerned with the general quality practices. The content of those sources was analyzed and the following themes were identified:a. Research theme 1: Guidelines of the pharmaceutical quality.b. Research theme 2: General practices recently applied in the pharmaceutical industry. Main outcome measures The following guidelines were identified and reviewed: WHO guidelines, FDA guidelines, EU guidelines and ICH guidelines in the research theme I. In research theme II; the following topics were identified and reviewed: quality risk management, quality by design, corrective actions and preventive actions, process capability analysis, Six Sigma, process analytical technology, lean manufacturing, total quality management, ISO series and HACCP. Results Upon reviewing the previously highlighted guidelines and the practices that are widely applied in the pharmaceutical industry, it was noticed that there is an abundant number of papers and articles that explain the general guidelines and practices but the literature lack those describing application; case studies of the pharmaceutical factories applying those guidelines and significance of those guidelines and practices. Conclusions It is recommended that the literature would invest more in the area of application and significance of guidelines and practices. New case studies should be done to prove the feasibility of such practices.

Comparative study between derivative spectrophotometry and multivariate calibration as analytical tools applied for the simultaneous quantitation of Amlodipine, Valsartan and Hydrochlorothiazide.

Four simple, accurate and specific methods were developed and validated for the simultaneous estimation of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in commercial tablets. The derivative spectrophotometric methods include Derivative Ratio Zero Crossing (DRZC) and Double Divisor Ratio Spectra-Derivative Spectrophotometry (DDRS-DS) methods, while the multivariate calibrations used are Principal Component Regression (PCR) and Partial Least Squares (PLSs). The proposed methods were applied successfully in the determination of the drugs in laboratory-prepared mixtures and in commercial pharmaceutical preparations. The validity of the proposed methods was assessed using the standard addition technique. The linearity of the proposed methods is investigated in the range of 2-32, 4-44 and 2-20 μg/mL for AML, VAL and HCT, respectively.

Simultaneous determination of domperidone maleate and cinnarizine in a binary mixture using derivative ratio spectrophotometry and classical least squares calibration

This work is concerned with the simultaneous determination of domperidone maleate (DOM) and cinnarizine (CINN) in a binary mixture form without previous separation by two different methods. The first method is the application of derivative ratio spectrophotometry where the linearity range was 2.5-30 micro g/ml, 2.5-25 micro g/ml for DOM and CINN, respectively, and percentage recoveries were 100.26+/-1.308 and 99.86+/-0.939 for DOM and CINN, respectively, in their laboratory prepared mixtures. The second method depends on the application of classical least squares (CLS) calibration model. Two training sets were constructed and the best model was used for the prediction of the concentrations of both drugs. The proposed procedures were successfully applied for the simultaneous determination of both drugs in laboratory prepared mixtures and in commercial tablet preparations. The validity of the proposed methods was assessed by applying the standard addition technique where the percentage recovery of the added standard was found to be 99.83+/-1.861 and 98.38+/-0.871 for DOM and CINN, respectively, using the derivative ratio method and 99.53+/-0.916 and 99.39+/-0.599 for DOM and CINN, respectively, using the CLS method. The proposed procedures are rapid, simple, require no preliminary separation steps and can, therefore, be used routine analysis of both drugs in quality control laboratories.

Comparative study of 2-hydroxy propyl beta cyclodextrin and calixarene as ionophores in potentiometric ion-selective electrodes for neostigmine bromide

Three novel neostigmine bromide (NEO) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using tetrakis(4-chlorophenyl)borate (TpClPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor 3 was constructed using 4-sulfocalix-8-arene as an ionophore. Linear responses of NEO within the concentration ranges of 10(-5) to 10(-2), 10(-6) to 10(-2) and 10(-7) to 10(-2) mol L(-1) were obtained using sensors 1, 2 and 3, respectively. Nernstian slopes of 51.6 ± 0.8, 52.9 ± 0.6 and 58.6 ± 0.4 mV/decade over the pH range of 4-9 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for NEO. The utility of 2-hydroxy propyl β-cyclodextrin and 4-sulfocalix[8]arene as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2 and 3 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of NEO in bulk powder, different pharmaceutical formulations, and biological fluids (plasma and cerebrospinal fluid (CSF)) and in the presence of its degradation product (3-hydroxyphenyltrimethyl ammonium bromide) and thus could be used for stability-indicating methods.

Sequential Spectrophotometric Method for the Simultaneous Determination of Amlodipine, Valsartan, and Hydrochlorothiazide in Coformulated Tablets

A new, simple and specific spectrophotometric method was developed and validated in accordance with ICH guidelines for the simultaneous estimation of Amlodipine (AML), Valsartan (VAL), and Hydrochlorothiazide (HCT) in their ternary mixture. In this method three techniques were used, namely, direct spectrophotometry, ratio subtraction, and isoabsorptive point. Amlodipine (AML) was first determined by direct spectrophotometry and then ratio subtraction was applied to remove the AML spectrum from the mixture spectrum. Hydrochlorothiazide (HCT) could then be determined directly without interference from Valsartan (VAL) which could be determined using the isoabsorptive point theory. The calibration curve is linear over the concentration ranges of 4–32, 4–44 and 6–20 μg/mL for AML, VAL, and HCT, respectively. This method was tested by analyzing synthetic mixtures of the above drugs and was successfully applied to commercial pharmaceutical preparation of the drugs, where the standard deviation is <2 in the assay of raw materials and tablets. The method was validated according to the ICH guidelines and accuracy, precision, repeatability, and robustness were found to be within the acceptable limits.

Different approaches in Partial Least Squares and Artificial Neural Network models applied for the analysis of a ternary mixture of Amlodipine, Valsartan and Hydrochlorothiazide.

Different chemometric models were applied for the quantitative analysis of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in ternary mixture, namely, Partial Least Squares (PLS) as traditional chemometric model and Artificial Neural Networks (ANN) as advanced model. PLS and ANN were applied with and without variable selection procedure (Genetic Algorithm GA) and data compression procedure (Principal Component Analysis PCA). The chemometric methods applied are PLS-1, GA-PLS, ANN, GA-ANN and PCA-ANN. The methods were used for the quantitative analysis of the drugs in raw materials and pharmaceutical dosage form via handling the UV spectral data. A 3-factor 5-level experimental design was established resulting in 25 mixtures containing different ratios of the drugs. Fifteen mixtures were used as a calibration set and the other ten mixtures were used as validation set to validate the prediction ability of the suggested methods. The validity of the proposed methods was assessed using the standard addition technique.

Spectrophotometric and spectrodensitometric methods for the determination of rivastigmine hydrogen tartrate in presence of its degradation product.

Three sensitive, selective and precise stability-indicating methods for the determination of the anti-Alzheimers drug, rivastigmine hydrogen tartrate (RIV) in the presence of its alkaline degradation product (major metabolite, NAP 226-90) and in pharmaceutical formulation were developed and validated. The first method is a second derivative (D(2)) spectrophotometric one, which allows the determination of RIV in the presence of its degradate at 262 nm (corresponding to zero crossing of the degradate) over a concentration range of 50-500 microg/ml with mean percentage recovery 100.18 +/- 0.628. The second method is the first derivative of the ratio spectra (DD(1)) by measuring the peak amplitude at 272 nm over the same concentration range as (D(2)) spectrophotometric method, with mean percentage recovery 99.97 +/- 0.641. The third method is a TLC-densitometric one, where RIV was separated from its degradate on silica gel plates using methanol:butanol:H(2)O:ammonia (5:4:1:0.01 v:v:v) as a developing system. This method depends on the quantitative densitometric evaluation of thin layer chromatogram of RIV at 263 nm over a concentration range of 20-160 microg/spot, with mean percentage recovery 100.19 +/- 1.344. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The proposed methods have been successfully applied to the analysis of RIV in pharmaceutical dosage forms without interference from other dosage form additives and the results were statistically compared with reference method.