Chemometric and Design of Experiments-Based Analytical Quality by Design and Green Chemistry Approaches to Multipurpose High-Pressure Liquid Chromatographic Method for Synchronous Estimation of Multiple Fixed-Dose Combinations of Azilsartan Medoxomil

Analytical Quality Risk Assessment and Design of Experiments to Green HPTLC Method for Simultaneous Estimation of Sildenafil Citrate and Dapoxetine Hydrochloride

A green and robust high-performance thin-layer chromatographic method has been developed for the simultaneous estimation of sildenafil citrate and dapoxetine hydrochloride. A fractional factorial design was applied for analytical quality risk assessment of potential analytical risk factors. The identified critical analytical risk factors were optimized using the design of experiment-based response surface analysis by full factorial design. The analytical design space was navigated for the optimization of the method and the control strategy was framed for low-risk life-cycle management of the chromatographic method. The chromatographic analysis of sildenafil and dapoxetine was carried out on a TLC plate coated with silica gel G60 F254 using n-butanol:ethyl acetate:ethanol (8.0 + 2.0 + 0.5, v/v) as mobile phase. The chromatographic peaks of sildenafil and dapoxetine were found to be at Rf 0.29 and 0.69, respectively. The method was found to be accurate, precise, robust, specific and sensitive. The fixed-dose combinations of sildenafil and dapoxetine were assayed and results were found in compliance with their labeled claim. The present method was developed using safe and eco-friendly organic solvents for the safety of analysts and the protection of the environment. The greenness profiles of developed and reported methods were evaluated using the NEMI scale and AGREE software.

Simultaneous Chromatographic Estimation of Vildagliptin and Dapagliflozin Using Hybrid Principles of White Analytical Chemistry and Analytical Quality by Design

BACKGROUND

The fixed-dose combination of vildagliptin (VDG) and dapagliflozin (DGZ) is used in the treatment of type 2 diabetes mellitus. According to the literature survey, RP-HPLC and HPTLC methods have been reported for routine analysis of VDG and DGZ. These chromatographic methods have been developed using potentially neurotoxic and teratogenic solvents, which are unsafe for human and aquatic animal life and hazardous to the environment. These types of organic solvents shall be replaced or reduced during chromatographic analysis of drugs for the safety of human and aquatic animal life and the protection of the environment. The novel white analytical chemistry (WAC) approach has been introduced, which emphasizes robust, green, user-friendly, economical, and rapid analysis of drug samples.

OBJECTIVE

Hence, the WAC-based RP-HPLC method has been developed for the estimation of VDG and DGZ using lower toxic and economical solvents.

METHOD

The development of the RP-HPLC method includes the implementation of the analytical quality by design approach using principles of design of experiments to reduce organic waste generation and regulatory compliance of analytical method. The central composite design was applied for response surface modeling (RSM) and optimization of the RP-HPLC method. The method validation was carried out according to ICH Q2 (R1) guidelines.

RESULTS

The fixed-dose combinations of VDG and DGZ were assayed, and results were found in compliance with their labeled claim. The published and proposed RP-HPLC methods were assessed for chromatographic analysis of VDG and DGZ using the Red-Green-Blue (RGB) model, AGREE calculator, Eco-Scale Assessment tool, GAPI software, and NEMI standards.

CONCLUSIONS

The proposed method was found to be robust, green, economical, and user-friendly for chromatographic analysis of VDG and DGZ. The proposed method can be an economical and eco-friendly analytical tool in the pharmaceutical industry for quality control and routine analysis of fixed-dose combinations of VDG and DGZ.

HIGHLIGHTS

Hybrid principles of WAC and analytical quality by design to RP-HPLC method for simultaneous estimation of VDG and DGZ in their fixed-dose combinations.

Principles of White Analytical Chemistry and Design of Experiments to Development of Stability-Indicating Chromatographic Method for the Simultaneous Estimation of Thiocolchicoside and Lornoxicam

BACKGROUND

A variety of chromatographic methods have been published for the stability evaluation of thiocolchicoside (THC) and lornoxicam (LNX). Nevertheless, the development of chromatographic methods requires the use of neurotoxic and teratogenic organic solvents that are detrimental to the environment and harmful to human life.

OBJECTIVES

Using the principles of design of experiments (DoE), a novel white analytical chemistry-driven stability-indicating high-performance thin-layer chromatographic (SI-HPTLC) method has been developed for the concurrent stability study of THC and LNX. To protect the environment and human life, the stability-indicating HPTLC method was developed using safe organic solvents.

METHOD

Potential analytical method risk parameters (AMRPs) and analytical method performance attributes (AMPAs) were screened using the fractional factorial design. The response surface analysis and optimization of critical AMRPs and AMPAs was carried out using full factorial design. Navigation of the method operable design region (MODR) was used to develop the SI-HPTLC technique. The developed method was validated in accordance with the International Council for Harmonization (ICH) Q2 (R1) guideline.

RESULTS

The developed method's greenness was evaluated using the AGREE (Analytical Procedure Greenness) tool and ESA (Eco-Scale Assessment). The Blue (B) model was used to assess the proposed method's cost and time efficiency and user-friendliness. For the stability studies of THC and LNX, the 12 principles of WAC (white analytical chemistry) were used to evaluate the published and proposed chromatographic techniques.

CONCLUSIONS

Compared to previously published chromatographic techniques for studying the stability of THC and LNX, the suggested approach was found to be more affordable, environmentally friendly, and user-friendly.

HIGHLIGHTS

The development of a stability-indicating HPTLC method using a novel white analytical chemistry approach and organic solvents with low toxicity potential. Application of the developed method for analysis of the forced degraded sample and fixed-dose combinations of THC and LNX.

Facile synthesis and eco-friendly analytical methods for concurrent estimation of selected pharmaceutical drugs in their solutions: application to quality by design, lean six sigma, and stability studies

Economical, highly robust, selective, precise, and eco-friendly RP-UPLC and spectrophotometric methods were developed and validated for the concurrent estimation of selected pharmaceutical drugs represented in ceftazidime (CFZ) and pyridine (PYD) in their solutions using Agilent Zorbax SB-C18 RRHD (50 × 2.1 mm, 1.8 μm) column at flow rate 0.3 mL/min with wavelength 254 nm. Box-Behnken design (BBD) established Response surface methodology (RSM) to achieve the optimum chromatographic condition with minimal trials conducted. Three independent variables specifically acetonitrile ratio 60-70%, pH 3-7, and temperature 25-35 °C were implemented to evaluate the influences of these variables on the responses as resolution and retention time. Desirability and overlay plots were carried out to adjust the optimal condition that achieved the shortest retention time of less than 2 min and desired resolution of more than 1.5 using a mobile phase consisting of acetonitrile: purified water (70:30, v/v) at pH 5.0 adjusted by 0.1% orthophosphoric acid with the column oven temperature 30 °C and column void volume 0.46 mL. Mean centering of ratio spectra (MCR) and ratio subtraction (RS) methods were effectively applied to resolve drugs' spectral superposition at 220 nm, 255.4 nm, 260.3 nm, and 254.6 nm for CFZ and PYD, respectively. Linearity range was accomplished for UPLC, MCR, and RS methods over the concentration range of 2-100, 1-50,3-30 and 5-30 µg/mL for CFZ and PYD, respectively with correlation coefficient > 0.999 and good recovery results within 98-102%. Six Sigma methodology was achieved using the process capability index (Cpk) to compare the suggested and USP methods showing that both are highly capable with Cpk > 1.33. The proposed method was successfully validated depending on ICH guidelines and ANOVA results and applied for the accelerated stability study.

Green analytical chemistry-driven response surface modeling to stability-indicating chromatographic method for estimation of cilnidipine and application of high-performance thin-layer chromatography-mass spectrometry for characterization of degradation products

Cilnidipine is a calcium channel blocker that is used to treat cardiac diseases such as angina and high blood pressure. Several column and planar chromatographic methods for estimating cilnidipine in pharmaceutical dosage forms have been documented. However, these method developments have been carried out employing organic solvents such as acetonitrile, methanol, toluene, chloroform, and others as mobile phase components or as sample pretreatment diluents. These organic solvents are neurotoxic and teratogenic to humans and aquatic animals, according to International Council for Harmonization Q3C (R8) recommendations. According to the green analytical chemistry approach, such organic solvents should be reduced or removed during the development of chromatographic methods for environmental protection and the safety of human and aquatic animal life. As a result, the stability-indicating chromatographic estimation of cilnidipine was performed utilizing less toxic organic solvents. To prevent organic solvent waste during method development, mobile-phase optimization was performed using the design of experiment-based response surface modeling. Cilnidipine has been subjected to hydrolysis, oxidation, photolysis, and dry-heat decomposition to determine its stability. The greenness profiles of the suggested and published chromatographic methods were examined using the national environment method index, analytical greenness calculator, green analytical procedure index software, and eco-scale assessment tool.

Red, Green, and Blue Model-Based Assessment and Principles of White Analytical Chemistry to Robust Stability-Indicating Chromatographic Estimation of Thiocolchicoside and Diclofenac Sodium

BACKGROUND

White analytical chemistry (WAC) is a recent approach for evaluating analytical procedures based on their effectiveness in validating results, capacity to be environmentally friendly, and economic effectiveness.

OBJECTIVE

The detection of diclofenac sodium (DCF) and thiocolchicoside (THC) simultaneously has been established using a WAC-driven stability-indicating chromatographic method (SICM).

METHODS

For the concurrent stability study of THC and DCF, the suggested chromatographic technique was developed employing safe and environmentally acceptable organic solvents. To identify critical analytical method parameters (AMPs) and analytical quality attributes (AQAs), a design of experiments (DoE)-based screening design was applied. For the DoE-based response surface modelling (RSM) of critical AMPs and AQAs, the Box-Behnken design (BBD) was employed.

RESULTS

A robust SICM was developed by navigating the analytical design space for simultaneous estimation of THC and DCF. IR, NMR, and mass spectral data were used to characterize the degradation products. Red, green, and blue (RGB) models were used to evaluate the suggested method's validation effectiveness, greenness power, and economic efficiency and compared to published chromatographic techniques. The effectiveness of the chromatographic method's validation concerning the International Council for Harmonization (ICH) Q2 (R1) guideline was evaluated using the red model. The analytical greenness (AGREE) evaluation tool and eco-scale assessment (ESA) approach were used to evaluate the green model's methodology. The blue model-based assessment was carried out for comparison of simplicity of instruments handling, cost, and time during sample analysis. The red, blue, and green scores of the techniques were averaged to arrive at the white score of the suggested and reported methods.

CONCLUSION

For the concurrent stability study of THC and DCF, the suggested technique was shown to be validated, environmentally friendly, and cost effective. The suggested approach could be a cost-effective and environmentally friendly analytical technique for determining the stability and monitoring the quality of fixed-dose combinations (FDC) of THC and DCF.

HIGHLIGHTS

Stability-indicating HPTLC method was developed for concomitant analysis of THC and DCF using concepts of DoE and WAC.

Quantitative analysis of two COVID-19 antiviral agents, favipiravir and remdesivir, in spiked human plasma using spectrophotometric methods; greenness evaluation

Favipiravir and remdesivir have been included in the COVID-19 treatment guidelines panel of several countries. The main objective of the current work is to develop the first validated green spectrophotometric methods for the determination of favipiravir and remdesivir in spiked human plasma. The UV absorption spectra of favipiravir and remdesivir have shown some overlap, making simultaneous determination difficult. Due to the considerable overlap, two ratio spectra manipulating spectrophotometric methods, namely, ratio difference and the first derivative of ratio spectra, enabled the determination of favipiravir and remdesivir in their pure forms and spiked plasma. The ratio spectra of favipiravir and remdesivir were derived by dividing the spectra of each drug by the suitable spectrum of another drug as a divisor to get the ratio spectra. Favipiravir was determined by calculating the difference between 222 and 256 nm of the derived ratio spectra, while calculating the difference between 247 and 271 nm of the derived ratio spectra enabled the determination of remdesivir. Moreover, the ratio spectra of every drug were transformed to the first order derivative using ∆λ = 4 and a scaling factor of 100. The first-order derivative amplitude values at 228 and 251.20 nm enabled the determination of favipiravir and remdesivir, respectively. Regarding the pharmacokinetic profile of favipiravir (C_max 4.43 µg/mL) and remdesivir (C_max 3027 ng/mL), the proposed methods have been successfully applied to the spectrophotometric determination of favipiravir and remdesivir in plasma matrix. Additionally, the greenness of the described methods was evaluated using three metrics systems: the national environmental method index, the analytical eco-scale, and the analytical greenness metric. The results demonstrated that the described models were in accordance with the environmental characteristics.

Green quality by design HPLC approach for the simultaneous determination of Bilastine and Montelukast

For the simultaneous estimation of two co-formulated antihistaminic drugs (Bilastine and Montelukast), a novel and eco-friendly reversed-phase HPLC approach with both diode array and fluorescence detection modes was designed. Rather than using the routine methodology, the Quality by Design (QbD) approach was adopted to speed up the method development and to test robustness of the method. To evaluate the effect of variable factors on chromatographic response, a full factorial design was used. The chromatographic separation was performed using isocratic elution on the C18 column. The mobile phase consists of 92% methanol, 6% acetonitrile, and 2% phosphate buffer with 0.1 (v/v) triethylamine adjusted to pH 3, it was pumped at a flow rate of 0.8 mL/min with an injection volume of 20 μL. The developed stability indicating HPLC approach was used to assess the stability of montelukast (MNT). It was subjected to a variety of stress conditions, including hydrolytic (acid-base), oxidative, thermal, and photolytic stress conditions. All of these conditions were found to have relevant degradation pathways. Under the described experimental conditions, MNT degradation followed pseudo-first-order kinetics. The kinetic parameters of its degradation (rate constant and t_1/2) were calculated and a proposal for the degradation pathway was postulated.

Green analytical chemistry and experimental design: a combined approach for the analysis of zonisamide

Green analytical chemistry principles, as well as experimental design, are a combined approach adopted to develop sensitive reproducible stability indicating HPLC method for Zonisamide (ZNS) determination. The optimal conditions for three chromatographic parameters were determined using a central composite design of the response surface. Kromasil C₁₈ column (150 mm × 4.6 mm, 5 µm) was utilized with ethanol, H₂O (30:70 v/v) as a mobile phase at a flow rate of 1 mL/min at 35 °C. Good reproducibility and high sensitivity were achieved along (0.5-10 µg/mL) concentration range. In contrast, the TLC-densitometric method was performed on aluminum plates precoated with silica gel 60F₂₅₄ as a stationary phase and chloroform: methanol: acetic acid (8:1.5:0.5 by volume) as a developing system. Reproducible results were obtained in the range of (2-10 μg/band). The chromatograms of HPLC and TLC were scanned at 280 nm and 240 nm, respectively. The suggested methods have been validated following ICH guidelines, and no statistically significant differences were detected between the results of the current study and the official USP method. It was also found that using experimental design implements the green concept by reducing the environmental impact. Finally, Eco-Scale, GAPI and AGREE were used to assess the environmental impacts of the suggested methods.

Sustainable chromatographic purification of milbemectin: Application of high-speed countercurrent chromatography coupled with off-line atmospheric pressure solid analysis probe-high resolution mass spectrometry

Isolation of valuable chemicals is an important process in reagent manufacturing for the pharmaceutical and food science industries. This process is traditionally time-consuming, expensive, and consumes vast amounts of organic solvents. Considering green chemistry and sustainability concerns, we sought to develop a sustainable chromatographic purification methodology for obtaining antibiotics by focusing on the reduction of organic solvent waste generation. Milbemectin (mixture of milbemycin A3 and milbemycin A4) was successfully purified using high-speed countercurrent chromatography (HSCCC) and pure fractions (>98% purity, HPLC) could be identified using the organic solvent fee atmospheric pressure solid analysis probe mass spectrometry (ASAP-MS). The organic solvents required for HSCCC could be redistilled and recycled for continued HSCCC purification, thus reducing the consumption of organic solvent (n-hexane/ethyl acetate) by 80+%. Optimization of the two-phase solvent system (n-hexane/ethyl acetate/methanol/water, 9/1/7/3, v/v/v/v) for HSCCC was assisted computationally, thereby reducing solvent waste from an experimental determination. Our proposal application of HSCCC and offline ASAP-MS provides proof of concept for a sustainable, preparative scale, chromatographic purification methodology for obtaining antibiotics in high purity.