Three developed spectrophotometric methods for determination of a mixture of ofloxacin and ornidazole; application of greenness assessment tools

TLC- smartphone for ofloxacin and dexamethasone determination in pharmaceutical formulation and rabbit aqueous humor

Preserving the environment and reducing the harmful effects of chemicals on it, is a primary goal of the research, nowadays. One of the major challenges for research is assessing the efficiency and quality of the proposed method in terms of environmental and human safety, as well as their overall cost. Thin layer chromatography (TLC)-Smartphone is a simple, cost-effective, and rapid method for the detection and quantification of analytes. This work describes the development of a green, white, sensitive and easy TLC method that employs a smartphone charge-coupled device (CCD) camera for image acquisition that provides data regarding the identity and quantity of ofloxacin (OFL) and dexamethasone (DEXA) in their mixture. A mixture of OFL and DEXA was separated on a silica gel 60 F254 plate using a mobile phase of n-butanol: acetic acid: water (6:2:2, by volume). Visualization of the separated spots was achieved using the "Universal Stain" iodine vapor (I2) and potassium permanganate (KMnO4), resulting in colored spots on the TLC plate. The Rf values of ofloxacin (0.25) and dexamethasone (0.8) were determined from the recorded images, enabling the identification of the drugs. It was possible to construct a linear calibration model and relate optical density with concentration per band. A linear calibration model was constructed to correlate optical density with concentration per band. A smartphone application was developed to calculate the spot intensity, which was then used to quantify ofloxacin and dexamethasone in their mixture. The TLC-Smartphone method produced linear calibration curves between the color intensity of each spot and the corresponding concentrations. For iodine vapor visualization, the linearity range was 10-50 μg/band for ofloxacin and 40-120 μg/band for dexamethasone. For KMnO4 visualization, the linearity was in the range of 10-50 μg/band for both drugs. The proposed method was validated following ICH guidelines, and was successfully applied for the estimation of ofloxacin and dexamethasone in their eye drop pharmaceutical form and rabbit aqueous humor.

Ecological multivariate assisted spectrophotometric methods for determination of antipyrine and benzocaine HCl in presence of antipyrine official impurity and benzocaine HCl degradant: toward greenness and whiteness

A simple and green chemometrics-assisted spectrophotometric technique has beendeveloped and validated for the determination of antipyrine (ANT) and benzocaine HCl (BEN) along with the official impurity of ANT, antipyrine impurity A (ANT imp-A), and the degradation product of BEN, p-amino benzoic acid (PABA), in their quaternary mixture. Three models were developed and compared: partial least squares (PLS), artificial neural networks (ANN), and multivariate curve resolution-alternating least squares (MCR-ALS) where the four studied drugs were successfully quantified. The quantitative determination of the studied drugs was assessed using percentage recoveries, standard errors of prediction, and root mean square errors of prediction. The ANN model demonstrated the lowest error and the best correlation making it the most accurate method for analysis. The models were constructed in the ranges of 5.0-9.0 µg mL-1 for ANT, 1.0-5.0 µg mL-1 for BEN, 0.5-2.5 µg mL-1 for ANT imp-A, and 0.25-1.25 µg mL-1 for PABA. The established models successfully determined ANT, BEN, ANT imp-A, and PABA with detection limits of 0.312, 0.178, 0.093, and 0.042 µg mL-1 for PLS, 0.185, 0.085, 0.001, and 0.034 µg mL-1 for ANN; and 0.473, 0.240, 0.073, and 0.069 µg mL-1 for MCR-ALS, respectively. The greenness and the whiteness of the proposed method were assessed using two green evaluating approaches: analytical Eco-scale, and AGREE, along with one white analytical chemistry evaluating tool, RGB. The three proposed models were successfully applied for determination of ANT and BEN in their pharmaceutically co-formulated dosage forms. They are also recommended for stability assays and purity testing of these drugs in quality control laboratories.

Three spectrophotometric quantitative analysis of bisoprolol fumarate and telmisartan in fixed-dose combination utilizing ratio spectra manipulation methods

Hypertension is a chronic condition with multiple drug regimens. Limiting these medicines is critical to patient compliance. Therefore, bisoprolol and telmisartan were recently developed in a fixed-dose combination to control blood pressure. The UV absorption spectra of bisoprolol and telmisartan overlapped significantly. Thus, three spectrophotometric methods have been developed for simultaneous determination of bisoprolol and telmisartan without prior separation. Method A is ratio difference of ratio spectra (RD), which measures the amplitude difference between (210-224) nm for bisoprolol and between (255-365) nm for telmisartan. Method B, the first derivative of ratio spectra (1DD), measures amplitude signals at 232 and 243 nm for bisoprolol and telmisartan, respectively. Method C is the mean centering of ratio spectra (MC), which measures the mean-centered ratio spectra's values at 223 nm for bisoprolol and 245 nm for telmisartan. The applied methods showed good linearity 2-20 µg/mL for bisoprolol, 4-32 µg/mL for telmisartan, with sufficient accuracy and precision. The methods were sensitive, with LOD values of 0.243 µg/mL and 0.596 µg/mL in RD method, 0.313 µg/mL and 0.914 µg/mL in 1DD method, and 0.406 and 0.707 µg/mL in MC method for bisoprolol and telmisartan, respectively, the methods were validated per ICH criteria. The novel methods are precise and accurate and can be used for routine analysis and quality control of bisoprolol and telmisartan in pure and dosage form. Furthermore, the greenness of the approaches was evaluated using Analytical Greenness assessment (AGREE), and the suggested method received a high greenness score.

Innovative voltammetric techniques for bumadizone analysis in pharmaceutical and biological samples: emphasizing green, white, and blue analytical approaches

There are no documented electroanalytical methods for quantifying the anti-inflammatory drug bumadizone (BUM) in pharmaceutical or biological matrices. So, a new voltammetric method was developed to determine BUM at nano concentrations in pharmaceutical forms, in the presence of its alkaline degradant, and in biological fluids. Five electrodes were tested, including three nano-reduced graphene oxide (nRGO) electrodes (5%, 15%, and 20%), a carbon paste electrode (CPE), and a 10% nRGO-modified CPE. The 10% nRGO-modified electrode showed the best performance, offering high selectivity and low detection limits, with good linearity in the concentration range of 0.9 × 102 to 15 × 102 ng mL-1. Differential pulse voltammetry successfully applied this electrode for BUM determination in various samples, achieving excellent recovery without preliminary separation. The method was validated according to ICH guidelines and compared favorably to the reference method. Its environmental impact was assessed using AGREE and Eco-scale metrics in addition to the RGB algorithm, showing superior greenness and whiteness profiles due to safer solvents and lower energy consumption, along with high practical effectiveness using the BAGI metric.

Continuous wavelet transform for solving the problem of minor components in quantitation of pharmaceuticals: a case study on the mixture of ibuprofen and phenylephrine with its degradation products

The presence of minor components represents a challenging problem in spectrophotometric analysis of pharmaceuticals. If one component has a low absorptivity or present in a low concentration compared to the other components, this will hinder its quantitation by spectrophotometric methods. Continuous Wavelet Transform (CWT) as a signal processing technique was utilized to figure out a solution to such a problem. A comparative study was established between traditional derivative spectrophotometry (Numerical Differentiation, ND) and CWT to indicate the advantages and limitations of each technique and possibility of solving the problem of minor components. A mixture of ibuprofen (IBU) and phenylephrine (PHE) with its degradation products forming a ternary mixture was used for comparing the two techniques. The two techniques were applied on raw spectral data and on ratio spectra data resulting in four methods, namely ND, CWT, Derivative Ratio-Zero Crossing (DRZC) and Continuous Wavelet Transform Ratio-Zero Crossing (CWTR-ZC) methods. By comparing the results in laboratory prepared mixtures, CWT technique showed advantages in analysis of mixtures with minor components than ND. The proposed methods were validated according to the ICH guideline Q2(R1), where their linearity was established with correlation coefficient ranging from 0.9995 to 0.9999. The linearity was in the range 3-40 μg/mL for PHE in all methods, while for IBU it was 20-180 and 30-180 μg/mL in CWT and ND methods, respectively. The CWT methods were applied for quantitative determination of the drugs in their dosage form showing the ability of the methods to quantitate minor components in pharmaceutical formulations.

Development of an eco-friendly HPLC method for the stability indicating assay of binary mixture of ibuprofen and phenylephrine

The development and validation of the stability indicating HPLC technique has contributed to the understanding of the stability profile of ibuprofen (IBU) and phenylephrine (PHE). Stability profile was achieved for PHE; the drug was found to be liable to be influenced by stress oxidative conditions; two oxidative degradants (Deg1 & Deg2) were formed and their structures were confirmed using IR and mass spectrometry. The drugs and degradation products were successfully separated using a gradient elution method on YMC-C8 column with 0.1% hexanesulfonic acid and acetonitrile as a mobile phase at pH 6.6. The flow rate was 1.0 mL/min, and a diode array detector operating at 220 nm was used for UV detection. The retention times of degradants Deg1, Deg2, ibuprofen (IBU), and phenylephrine hydrochloride (PHE) were 2.0, 2.2, 3.2 and 7.0 min, respectively. The proposed method was validated with respect to linearity, accuracy, precision, specificity, and robustness using ICH guidelines. The linearities of ibuprofen and phenylephrine hydrochloride were in the range of 10-100 μg/mL and 0.3-10 μg/mL, respectively. The % recoveries of the two drugs were found to be 100.75 ± 1.44%, 99.67% ± 1.67, and the LOD was found to be 2.75/mL and 0.09/mL for IBU, and PHE, respectively. The method was successfully applied to the estimation of ibuprofen and phenylephrine hydrochloride combination in pharmaceutical dosage form. The proposed technique was validated using ICH guidelines and its greenness was assessed according to Analytical Eco Scale metric (AES). Molecular docking was used to assess the two drugs and PHE oxidative degradants interaction with the stationary phase and to confirm the outcomes of the proposed method with regard to the order of elution of the two drugs and PHE degradation products. Eco-friendly and environmental safety were assessed through the application of one of the most applicable greenness assessment tool; Analytical Eco Scale metric (AES).