Smart chemometrics-assisted spectrophotometric methods for efficient resolution and simultaneous determination of paracetamol, caffeine, drotaverine HCl along with three of their corresponding related impurities

Three novel, simple and accurate multivariate spectrophotometric assisted mathematical techniques were developed for determination of paracetamol, caffeine, drotaverine HCl and their related impurities. The used multivariate algorithms are principal component regression (PCR), partial least squares (PLS), and synergy intervals partial least squares (siPLS). Linearity of the suggested methods was found to be (1.00-14.60, 1.40-7.00, 1.40-3.80, 1.00-3.00, 1.50-3.50 and 2.50-4.50 µg/mL) for paracetamol, caffeine, drotaverine HCl, and their related impurities; p-aminophenol, theophylline and homoveratric acid, correspondingly. The presented methods were effectively implemented in the determination of the cited compounds in their laboratory prepared mixtures. Commercially available tablet preparation was also analyzed using the applied methods where no impurities were detected and without interference from tablet additives. Moreover, statistical analysis did not reveal any noticeable differences between the obtained results and those acquired from the reported method in terms of accuracy and precision. The developed multivariate algorithms were validated by means of internal and external validation sets. The obtained results showed the siPLS algorithm's superiority to PCR and PLS according to the values of correlation coefficient values (r) and the lowest root mean square error of prediction (RMSEP). The combination of four subintervals [10, 12, 14, and 17] produced the highest efficiency model. Furthermore, these methods may be an applicable substitute to HPLC ones in quality control laboratories during rush of analyses where several samples have to be analyzed in a short time.

A reversed-phase-high performance liquid chromatography method for simultaneous determination of paracetamol, caffeine, drotaverine HCl and their related impurities with dissolution profiling of their tablets and greenness profile assessment

A sensitive, specific and eco-friendly reversed-phase-HPLC method was developed and validated for the determination of paracetamol, caffeine and drotaverine HCl along with their related impurities. The separation was accomplished using an X-bridge C₁₈ column (5 μm; 250 mm × 4.6 mm inner diameter) and a green mobile phase consisting of methanol and 0.02 M phosphate buffer at pH 5.0 in the gradient elution mode. The detector used was a diode array detector. The proposed method was validated in accordance with the International Conference on Harmonisation guidelines. Linear regressions were found in the range of 1-100, 1-100, 2-60, 1-20, 0.50-30 and 1-15 μg/mL for paracetamol, caffeine, drotaverine HCl, p-aminophenol, theophylline and 3,4-dimethoxyphenylacetic acid, respectively. The suggested method was successfully applied for the determination of the studied drugs in their tablet dosage form without interference from any excipients. No discernible difference was found between the obtained results and official or reported methods, statistically, in terms of both accuracy and precision. Dissolution profiling of the studied tablet was also performed using the suggested procedure. Moreover, the greenness profile was assessed using three different tools, namely, the National Environmental Methods Index, the Analytical Eco-Scale and the Analytical GREEnness Metric Approach. The acquired results assert the agreement of the assay with green chemistry principles.

Ecofriendly Simple UV Spectrophotometric and Chemometric Methods for Simultaneous Estimation of Paracetamol Aceclofenac and Eperisone Hydrochloride in Pharmaceutical Formulation: Assessment of Greenness Profile

This work introduces three eco-friendly UV spectrophotometric methods for the simultaneous estimation of Paracetamol, Aceclofenac and Eperisone Hydrochloride in pharmaceutical tablet formulation. The procedures employed were simultaneous equation method and multivariate chemometric methods with phosphate buffer pH 7.80 as diluent. The simultaneous equation method encompasses absorbance measurement at three different wavelengths (λmax of the drugs). It exhibits linearity between 12–18 µg mL−1 for paracetamol, 3.69–5.53 µg mL−1 for Aceclofenac, and 2.76–4.15 µg mL−1 Eperisone hydrochloride. The results obtained for accuracy and precision by the simultaneous equation method were within the permissible limits. Principal component regression and partial least squares were the tools used for chemometric methods. The calibration set and prediction set were constructed, and the UV spectra were recorded in zero order mode, further subjected to chemometric analysis. The % recoveries obtained for Paracetamol, Aceclofenac, and Eperisone Hydrochloride by chemometric techniques showed good accuracy, and the results obtained for analytical figures of merit were acceptable. Statistical comparison of the assay results obtained for the proposed methods showed no significant difference found among the methods using one way analysis of variance. Greenness evaluation tools revealed the greenness profile of the proposed methods and found them to be ecofriendly. The described methods were appropriate for routine quality control laboratories, facilitating eco-friendly, fast, and cost effective determination of Paracetamol, Aceclofenac, and Eperisone Hydrochloride in Acemyoset P tablets.

Simultaneous Determination of Drugs Affecting Central Nervous System (CNS) in Bulk and Pharmaceutical Formulations Using Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS)

The quality of medications is important to maintain the overall health care of patients. This study aims to develop and validate a spectrophotometric method using multivariate curve resolution-alternating least squares (MCR-ALS) with correlation constraint for simultaneous resolution and quantification of selected drugs affecting the central nervous system (imipramine, carbamazepine, chlorpromazine, haloperidol, and phenytoin) in different pharmaceutical dosage forms. Figures of merit such as root-mean-square error of prediction, bias, standard error of prediction, and relative error of prediction for the developed method were calculated. High values of correlation coefficients ranged between 0.9993 and 0.9998 reflected high predictive ability of the developed method. The results are linear in the concentration range of 0.3-5 μg/mL for carbamazepine, 0.3-15 μg/mL for chlorpromazine, 0.5-10 μg/mL for haloperidol, 0.5-10 μg/mL for imipramine, and 3-20 μg/mL for phenytoin. The optimized method was successfully applied for the analysis of the studied drugs in their pharmaceutical products without any separation step. The optimized method was also compared with a reported HPLC method using Student's t test and F ratio at 95% confidence level, and the results showed no significant difference regarding accuracy and precision. The proposed chemometric method is fast, reliable, and cost-effective and can be used as an eco-friendly alternative to chromatographic techniques for the analysis of the studied drugs in commercial pharmaceutical products.

Different applications of isosbestic points, normalized spectra and dual wavelength as powerful tools for resolution of multicomponent mixtures with severely overlapping spectra

Background

Analysis of complex mixture containing three or more components represented a challenge for analysts. New smart spectrophotometric methods have been recently evolved with no limitation. A study of different novel and smart spectrophotometric techniques for resolution of severely overlapping spectra were presented in this work utilizing isosbestic points present in different absorption spectra, normalized spectra as a divisor and dual wavelengths. A quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PCT) and para-aminophenol (PAP) was taken as an example for application of the proposed techniques without any separation steps. The adopted techniques adopted of successive and progressive steps manipulating zero /or ratio /or derivative spectra. The proposed techniques includes eight novel and simple methods namely direct spectrophotometry after applying derivative transformation (DT) via multiplying by a decoding spectrum, spectrum subtraction (SS), advanced absorbance subtraction (AAS), advanced amplitude modulation (AAM), simultaneous derivative ratio (S¹DD), advanced ratio difference (ARD), induced ratio difference (IRD) and finally double divisor–ratio difference-dual wavelength (DD-RD-DW) methods.

Results

The proposed methods were assessed by analyzing synthetic mixtures of the studied drugs. They were also successfully applied to commercial pharmaceutical formulations without interference from other dosage form additives. The methods were validated according to the ICH guidelines, accuracy, precision, repeatability, were found to be within the acceptable limits.

Conclusion

The proposed procedures are accurate, simple and reproducible and yet economic. They are also sensitive and selective and could be used for routine analysis of complex most of the binary, ternary and quaternary mixtures and even more complex mixtures.

Evaluation of the efficiency of continuous wavelet transform as processing and preprocessing algorithm for resolution of overlapped signals in univariate and multivariate regression analyses; an application to ternary and quaternary mixtures

Wavelets have been adapted for a vast number of signal-processing applications due to the amount of information that can be extracted from a signal. In this work, a comparative study on the efficiency of continuous wavelet transform (CWT) as a signal processing tool in univariate regression and a pre-processing tool in multivariate analysis using partial least square (CWT-PLS) was conducted. These were applied to complex spectral signals of ternary and quaternary mixtures. CWT-PLS method succeeded in the simultaneous determination of a quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PAR) and p-aminophenol (PAP, the major impurity of paracetamol). While, the univariate CWT failed to simultaneously determine the quaternary mixture components and was able to determine only PAR and PAP, the ternary mixtures of DRO, CAF, and PAR and CAF, PAR, and PAP. During the calculations of CWT, different wavelet families were tested. The univariate CWT method was validated according to the ICH guidelines. While for the development of the CWT-PLS model a calibration set was prepared by means of an orthogonal experimental design and their absorption spectra were recorded and processed by CWT. The CWT-PLS model was constructed by regression between the wavelet coefficients and concentration matrices and validation was performed by both cross validation and external validation sets. Both methods were successfully applied for determination of the studied drugs in pharmaceutical formulations.

Multicomponent spectrometric analysis of riboflavin and photoproducts and their kinetic applications

Riboflavin (RF) is a light sensitive compound and is known to form a number of photoproducts. These photoproducts possess the same nucleus and may interfere in the analysis of RF by UV and visible spectrometry. Therefore, it is necessary to apply the methods of multicomponent spectrometric analysis to quantify the vitamin and its photoproducts accurately. Such methods are useful in the study of the kinetics of photodegradation reactions of RF to obtain accurate and reliable results. Any interference in these methods due to linear or nonlinear irrelevant absorption of the minor unknown products can be accounted for by the application of appropriate correction procedures prior to kinetic treatment. Various factors affecting the accuracy, precision and selectivity of these analytical procedures are also discussed. This review highlights the principles and applications of multicomponent spectrometric methods and their application to the simultaneous determination of RF and its major photoproducts in degraded solutions to evaluate the kinetics of degradation.

Kinetic spectrophotometric H-point standard addition method for the simultaneous determination of diloxanide furoate and metronidazole in binary mixtures and biological fluids

Simple, reliable, and sensitive kinetic spectrophotometric method has been developed for the simultaneous determination of diloxanide furoate and metronidazole using H-point standard addition method (HPSAM). The method is based on the oxidation rate difference of diloxanide and metronidazole by potassium permanganate in basic medium. A green color has been developed and measured at 610 nm. Different experimental parameters were carefully optimized. The limiting logarithmic and the initial-rate methods were adopted for the construction of the calibration curve of each individual reaction with potassium permanganate. Under the optimum conditions, Beer's law was obeyed in the range of 1.0-20.0 and 5.0-25.0 μg ml(-1) for diloxanide furoate and metronidazole, respectively. The detection limits were 0.22 μg ml(-1) for diloxanide furoate and 0.83 μg ml(-1) for metronidazole. Correlation coefficients of the regression equations were greater than 0.9970 in all cases. The precision of the method was satisfactory; the maximum value of relative standard deviation did not exceed 1.06% (n=5). The accuracy, expressed as recovery was between 99.4% and 101.4% with relative error of 0.12 and 0.14 for diloxanide furoate and metronidazole, respectively. The proposed method was successfully applied for the simultaneous determination of both drugs in pharmaceutical dosage forms and human urine samples and compared with alternative HPLC method.

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

BACKGROUND

Metronidazole (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.

RESULTS

Method (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.

CONCLUSION

The 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