A novel quality by design approach for development and validation of a green reversed-phase HPLC method with fluorescence detection for the simultaneous determination of lesinurad, febuxostat, and diflunisal: Application to human plasma

Computer-assisted multifactorial method development for the streamlined separation and analysis of multicomponent mixtures in (Bio)pharmaceutical settings

The (bio)pharmaceutical industry is rapidly moving towards complex drug modalities that require a commensurate level of analytical enabling technologies that can be deployed at a fast pace. Unsystematic method development and unnecessary manual intervention remain a major barrier towards a more efficient deployment of meaningful analytical assay across emerging modalities. Digitalization and automation are key to streamline method development and enable rapid assay deployment. This review discusses the use of computer-assisted multifactorial chromatographic method development strategies for fast-paced downstream characterization and purification of biopharmaceuticals. Various chromatographic techniques such as reversed-phase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC), ion exchange chromatography (IEX), hydrophobic interaction chromatography (HIC), and supercritical fluid chromatography (SFC) are addressed and critically reviewed. The most significant parameters for retention mechanism modelling, as well as mapping the separation landscape for optimal chromatographic selectivity and resolution are also discussed. Furthermore, several computer-assisted approaches for optimization and development of chromatographic methods of therapeutics, including linear, nonlinear, and multifactorial modelling are outlined. Finally, the potential of the chromatographic modelling and computer-assisted optimization strategies are also illustrated, highlighting substantial productivity improvements, and cost savings while accelerating method development, deployment and transfer processes for therapeutic analysis in industrial settings.

Analytical quality by design approach for the development of high-performance liquid chromatography method for simultaneous analysis of metformin and sitagliptin in the presence of major degradation products

An analytical quality by design-based high-performance liquid chromatography method for determining metformin (MET) and sitagliptin (SIT) in stress-degraded samples was developed and validated. The analytical target profile and risk assessment-driven critical method variables, for example, pH, % aqueous, and buffer concentration, were studied for their effect on method responses of retention time and resolution using a central composite design. The correlation regression coefficient was more than 0.8, and variables interaction was significant on method responses with curvature effect. The method operable design region afforded an aqueous range of 55%-70% and an ortho-phosphoric acid buffer of 0.1% with a pH of 3.0-4.0 as a robust region for the suitable method performance characteristics. The separation of MET and SIT from their degradants (m/z 85.0509; m/z 193.0694) on the C8 column was achieved using a mobile phase consisting of 0.1% ortho-phosphoric acid and methanol (60:40% v/v; pH 3.0). The optimized method eluted MET and SIT at 4.3 ± 0.2 and 7.1 ± 0.2 min, respectively, with acceptable specificity and resolution. The linearity ranges of 25-250 μg/mL (r2 : 0.9982) and 5-50 μg/mL (r2 : 0.9989) was established for MET and SIT, respectively. The % recovery (98.81%-102.17%), precision (0.55%-1.65%), and robustness study for method variables were acceptable.

A brief review on application of design of experiment for the analysis of pharmaceuticals using HPLC

The quality pioneer Dr. Joseph M. Juran first proposed the idea of quality by design. According to him, pharmaceutical quality by design is an organised approach to product development that starts with predetermined goals and places an emphasis on product, process understanding, control based on reliable science and quality risk management. The quality of a product or process can typically be affected by a number of input elements. Design of experiments has been employed widely recently to understand the impacts of multidimensional and interactions of input parameters on the output responses of analytical procedures and pharmaceutical goods. Depending on the design of experiments objectives, screening, characterization, or optimization of the process and formulation, a variety of designs, such as factorial or mixture, can be used. The most popular designs used in the stage of screening or factor selection are the 2-Level Factorial and Plackett-Burman designs, both of which have two levels for each factor (k), both economical and effective, and in optimization widely used designs in this step are full factorial at three levels, central composite, Box-Behnken design. The analysis of variance, regression significance, and lack of fit of the regression model were some of the key topics covered in the discussion of the main components of multiple regression model adjustment. Design of experiments is thus the primary element of the formulation and analytical quality by design. The details about design of experiments used for the analysis of pharmaceutical formulation using HPLC.

Raman Spectroscopy for the Quantitative Analysis of Solid Dosage Forms of the Active Pharmaceutical Ingredient of Febuxostat

Raman spectroscopy has been used to characterize and quantify the solid dosage forms of the commercially available drug febuxostat. For this purpose, different formulations consisting of the febuxostat (API) and excipients with different concentrations of the API are prepared and analyzed by Raman spectroscopy to identify different spectral features related to the febuxostat API and excipients. Multivariate data analysis tools such as principal component analysis (PCA) and partial least-squares regression (PLSR) analysis are used for qualitative and quantitative analyses. PCA has been found to be useful for the qualitative monitoring of various solid dosage forms. PLSR analysis has led to the successful prediction of API concentration in the unknown samples with a sensitivity and a selectivity of 98 and 99%, respectively. Moreover, the root-mean-square error (RMSE) of calibration and validation of the PLSR model has been found to be 2.9033 and 1.35, respectively. Notably, it is found to be very helpful for the comparison between the self-made formulations of febuxostat and commercially available febuxostat tablets (40 and 80 mg) of two different brands (Gouric and Zurig). These results showed that Raman spectroscopy can be a useful and reliable technique for identifying and quantifying the active pharmaceutical ingredient (API) in commercially available solid dosage forms.

Novel experimental design paradigm for development of eco-friendly gradient chromatographic method for simultaneous determination of metronidazole and spiramycin

This work describes the innovative experimental design-assisted development of a green gradient chromatographic method for concomitant analysis of metronidazole (MTR) and spiramycin (SPR). Two different designs including fractional factorial and Box-Behnken designs were implemented for screening and optimization steps, respectively. The optimum chromatographic conditions involved a mobile phase consisting of ethanol and 20 mM sodium dihydrogen phosphate solution (pH adjusted to 2.5) in the ratio 2:98 (v/v) for 2 min then the ratio changed to 30:70 (v/v). The flow rate was 1.3 mL/minute. Separation and analysis were performed on X-bridge C18 (150 mm × 4.6 mm × 3.5 μm) column with diode array detector set at 230 nm. Column oven temperature was 40°C. A linear response was acquired over the range of 5-125 μg/mL for both drugs. Detection and quantitation limits were 0.86 and 2.62 μg/mL for MTR and 0.92 and 2.83 μg/mL for SPR, respectively. The method was implemented for determination of both drugs in three tablet formulations. The method was proved to be green as evaluated by three assessment tools. The application of experimental designs assists in development of a robust green chromatographic method in gradient elution mode for determination of both drugs within reasonable time.

Simultaneous Determination of Posaconazole and Hemp Seed Oil in Nanomicelles through RP-HPLC via a Quality-by-Design Approach

The present study involves the development of a reverse-phase HPLC method employing the quality-by-design methodology for the estimation of posaconazole and hemp seed oil simultaneously in nanomicelles formulation. The successful separation of posaconazole and hemp seed oil was achieved together, and this is the first study to develop and quantify posaconazole and hemp seed oil nanomicelles with linoleic acid as the internal standard and developed a dual drug analytical method employing a quality-by-design approach. The study was performed on a Shimadzu Prominence-I LC-2030C 3D Plus HPLC system with a PDA detector and the Shim-pack Solar C8 column (250 mm × 4.6 mm × 5 μm) for analysis with a mobile phase ratio of methanol:water (80:20% v/v) maintaining the flow rate of 1.0 mL/min. The final wavelength was selected as 240 nm and the elution of hemp seed oil and posaconazole was obtained at 2.7 and 4.6 min, respectively, with a maximum run time of 8.0 min. Box Behnken design was employed to optimize the method, keeping the retention time, peak area, and theoretical plates as dependent variables, while the mobile phase composition, flow rate, and wavelengths were chosen as independent variables. Parameters such as specificity, accuracy, robustness, linearity, sensitivity, precision, ruggedness, and forced degradation study were performed to validate the method. The calibration curves of posaconazole and hemp seed oil were determined to be linear throughout the range for concentration. The suggested approach can be effectively utilized for estimating the content of drugs from their nanoformulation and proved suitable for both in vivo and in vitro research.

Multi-spectroscopic assay methods for concurrent determination of recent anti-gout combination, a comparative study

Recently, Chemometric calibration methods in spectrophotometric analysis are achieving significant attention in the quality control of resolving drug mixtures and pharmaceutical formulations containing two or more drugs with overlapping spectra. The simple univariate methods have been used over the last few decades and has proven to be highly efficient and easy to apply. In this study, a comparative study was performed between some univariate and multivariate methods to determine if chemometric methods can substitute univariate methods in pharmaceutical analysis. In this study, three chemometric techniques were compared to seven univariate techniques to resolve a mixture of mefenamic acid and febuxostat in their raw materials, dosage forms and spiked human plasma. Mefenamic acid and febuxostat were used together for treatment of gout. The applied chemometric methods are partial least squares (PLS), artificial neural network (ANN) and genetic algorithm partial least squares (GA-PLS), while the used univariate methods include first derivative, second derivative, ratio spectra, derivative ratio spectra, ratio subtraction, Q-Absorbance ratio and mean centering spectrophotometric methods. The ten proposed methods were found to be green, sensitive, and rapid. They are simple and did not require any pre-separation steps. The results of both univariate and multivariate approaches were statistically compared with the reported spectrophotometric methods using student's t test and ratio variance F-test. They were also compared with each other, using one-way analysis of variance (ANOVA). These methods were assessed and validated according to ICH guidelines. The studied drugs were analyzed in their pharmaceutical dosage forms and spiked human plasma with good recoveries using the developed methods, which qualify them for routine quality control of the studied drugs.

Hydro-organic mobile phase and factorial design application to attain green HPLC method for simultaneous assay of paracetamol and dantrolene sodium in combined capsules

The greenness of any analytical method has become a very important aspect of a good analytical method. However, most chromatographic methods depend on the usage of relatively large amounts of lethal and un-decaying chemicals and solvents. So, a green approach based on the full factorial design was employed to develop a simple and rapid HPLC technique for concurrent determination of paracetamol and dantrolene sodium in their combined capsules. Both drugs are highly recommended to be administered together in patients with severe musculoskeletal disorders. Avoiding the routine methodology and resorting to the modern technology represented in the usage of experimental design allows rapid determination of the studied drugs using the optimum quantity of chemicals to avoid any waste of resources. Simultaneous separation of a binary mixture of paracetamol and dantrolene sodium was accomplished using a reversed phase Hypersil C18 column using an eco-friendly isocratic eluent. The used mobile phase consisted simply of ethanol: water (40:60, v/v). Orthophosphoric acid was used to adjust the pH of the mobile phase to 4.5. Triethanolamine (0.2%) was added aiming to reduce the peak tailing. The assay was completed within less than 6 min adopting 0.8 mL/min as a flow rate. The detection was carried out using a UV-detector at 290 nm. The suggested technique shows a linear correlation over concentration ranges of 1.0-200 and 1.0-40 µg/mL for paracetamol and dantrolene sodium, respectively. The suggested technique allowed the simultaneous analysis of the two co-formulated drugs in their synthetic mixture and combined capsule. The suggested technique is considered a greener substitute for the other reported HPLC techniques through the usage of safer solvents and chemicals, along with decreasing both waste output and analysis time. The method is accurate with recoveries between 97.85 and 101.27%, precise, as %RSD for the intraday and interday precision were between 0.39 and 1.72% and very sensitive with limits of detection (LOD)'s 0.15 and 0.18 µg/ml and limits of quantification (LOQ)'s 0.48 and 0.61 µg/ml for paracetamol and dantrolene sodium, respectively. The method greenness was ensured through its assessment by four greenness metrics. It is also validated following the International Conference on Harmonization Guidelines. The recommended technique could be a good alternative to traditional methods in the routine quality control analysis of the studied drugs due to its minimum harm to the planet or human beings.

Application of quality-by-design for adopting an environmentally green fluorogenic determination of benoxinate hydrochloride in eye drops and artificial aqueous humour

Herein, a sensitive and selective spectrofluorimetric method has been developed for the determination of the ocular local anesthetic benoxinate hydrochloride (BEN-HCl) in eye drops and artificial aqueous humour. The proposed method is based on the interaction of fluorescamine with the primary amino group of BEN-HCl at room temperature. Following the excitation of the reaction product at 393 nm, the emitted relative fluorescence intensity (RFI) was measured at 483 nm. The key experimental parameters were carefully examined and optimized by adopting an analytical quality-by-design approach. The method used a two-level full factorial design (2⁴ FFD) to obtain the optimum RFI of the reaction product. The calibration curve was linear at the range of 0.10-1.0 μg/mL of BEN-HCl with sensitivity down to 0.015 μg/mL. The method was applied for analyzing the BEN-HCl eye drops and could also assess its spiked levels in artificial aqueous humour with high % recoveries (98.74-101.37%) and low SD values (≤ 1.11). To investigate the green profile of the proposed method, a greenness assessment was performed with the aid of the Analytical Eco-Scale Assessment (ESA) and GAPI. The developed method obtained a very high ESA rating score in addition to being sensitive, affordable, and environmentally sustainable. The proposed method was validated according to ICH guidelines.

Analytical quality-by-design approach for development and validation of HPLC method for the simultaneous estimation of omarigliptin, metformin, and ezetimibe: application to human plasma and dosage forms

A simple, selective, and sensitive RP-HPLC method was proposed for the simultaneous determination of two co-administered antidiabetic drugs (omarigliptin and metformin) with an anti-hyperlipidemic drug (ezetimibe) in a medicinally-recommended ratio of 2.5:50:1, respectively. The proposed procedure was optimized by adopting a quality-by-design approach. The influence of different factors on chromatographic responses was optimized by applying the two-level full factorial design (2⁵). The optimum chromatographic separation was achieved using Hypersil BDS C18 column at 45 °C, and the mobile phase pumped isocratically composed of methanol: potassium dihydrogen phosphate buffer (6.6 mM; pH 7, 67:33% v/v) at a flow rate of 0.814 mL/min using 235 nm as a detection wavelength. The developed method was capable of separating this novel mixture in less than 8 min. The calibration plots of omarigliptin, metformin, and ezetimibe showed acceptable linearity over the ranges of 0.2-2.0, 0.5-25.0, and 0.1-2.0 µg/mL with quantitation limits of 0.06, 0.50, and 0.06 µg/mL, respectively. The proposed method was successfully applied to determine the studied drugs in their commercial tablets with high % recoveries (96.8-102.92%) and low % RSD values (less than 2%). The applicability of the method was extended to the in-vitro assay of the drugs in spiked human plasma samples with high % recoveries (94.3-105.7%). The suggested method was validated in accordance with ICH guidelines.

Developing an improved UHPLC method for impurity profile analysis of ceftriaxone using analytical quality by design

In this study, we developed a new reversed-phase ultra-high-performance liquid chromatography (UHPLC) method for comprehensively measuring impurities in ceftriaxone. The method was developed based on the Chinese Pharmacopoeia (ChP) HPLC method, which is limited by the lack of selectivity to potential impurities and a long running time. Screening experiments showed that octylamine concentration, mobile phase pH, and organic phase ratio were critical method parameters. Further optimisation and Monte-Carlo simulations were performed to map out the design space. The selected working conditions resulted in a complete separation of the impurity profile in approximately 10 min. A multivariate approach confirmed that the method was robust, and the proportion of acetonitrile should be carefully controlled. Additionally, the developed UHPLC method could be transferred back to HPLC in a single step using a Columns Calculator, providing a new approach for the rapid and effective development of the HPLC method. Our findings could serve as a reference for developing the next version of the ChP.

A quality-by-design eco-friendly UV-HPLC method for the determination of four drugs used to treat symptoms of common cold and COVID-19

An optimization approach based on full factorial design was employed for developing an HPLC-UV method for simultaneous determination of a quaternary mixture used for the treatment of symptoms related to common cold and COVID-19. The quaternary mixture is composed of paracetamol, levocetirizine dihydrochloride, phenylephrine hydrochloride and ambroxol hydrochloride. The developed technique is a green, fast and simple method that uses isocratic elution of mobile phase consisting of 20:5:75 (v/v) of ethanol: acetonitrile: 2.5 mM heptane-1-sulphonic acid sodium salt at pH 6.5 [Formula: see text] 0.02. The chromatographic separation was carried out using Hypersil BDS Cyano LC Column (250 × 4.6 mm, 5 μm) with 230 nm UV detection and 1.0 mL/min. flow rate. Avoiding the routine methodology and resorting to the modern technology-represented in the usage of experimental design-allows rapid determination of the four drugs using the optimum quantity of chemicals to avoid any waste of resources. The quaternary mixture was eluted in less than 9 min., where retention times of paracetamol, levocetirizine dihydrochloride, phenylephrine hydrochloride and ambroxol hydrochloride were found to be 2.2, 3.8, 6.6 and 8.8 min., respectively. The calibration graphs of the four drugs were linear over concentration ranges of 50.0-500.0, 0.5-20.0, 0.5-20.0 and 0.5-100.0 µg/mL for paracetamol, levocetirizine dihydrochloride, phenylephrine hydrochloride and ambroxol hydrochloride, respectively with correlation coefficients higher than 0.999. The method is accurate with mean recoveries between 99.87 and 100.04%, precise, as %RSD for the intraday and interday precision were between 0.61 and 1.64% and very sensitive with limit of detections (LOD)'s between 29 and 147 ng/mL and limit of quantification (LOQ)'s between 95 and 485 ng/mL. The proposed method was successfully applied for the analysis of the four drugs either in raw materials or in prepared tablet with the least amount of chemicals within short time. It is also validated following International Conference on Harmonization Guidelines. The proposed method was found to be green according to the most common greenness assessment tools; NEMI, GAPI, Analytical Eco-Scale and AGREE methods. The advantages of the proposed method qualify it for routine analysis of the studied drugs either in single or co-formulated dosage form in quality control labs.

Optimization and validation of liquid-liquid extraction with low-temperature purification (LLE-LTP) for determining fluopyram fungicide in water samples using HPLC-DAD

Fluopyram is a fungicide and nematicide that belongs to the chemical group of benzamides, which act as succinate dehydrogenase inhibitors (SDHIs) on the mitochondrial respiratory chain of fungi. Despite being well known in several countries, there are few studies involving the optimization and validation of extraction methods for determining fluopyram in water samples. Therefore, this study aimed to optimize and validate liquid-liquid extraction with low-temperature purification (LLE-LTP) to determine fluopyram fungicide in water samples using high-performance liquid chromatography with diode array detection (HPLC-DAD). A two-level full factorial design was employed to optimize LLE-LTP which enabled achieving a recovery rate close to 100% and relative standard deviations (RSD) < 10.0%. The validation showed that the extraction method may be considered selective, precise, accurate, and linear in the range of 6.0 to 200 μg L^-1. The LOD and LOQ were 4.0 and 6.0 μg L^-1, respectively, proving the efficiency of this method for trace level determination of this fungicide in water samples. LLE-LTP coupled to HLPC-DAD analysis showed a matrix effect of less than 8% and it was applied in monitoring 20 environmental water samples, but no fluopyram residue was detected in the samples.

Quantification and Determination of Stability of Tylvalosin in Pig Plasma by Ultra-High Liquid Chromatography with Ultraviolet Detection

Tylvalosin (TV) is a macrolide antibiotic that is used for treating respiratory and enteric bacterial infections in swine and in poultry. In the coming years, the use of this drug will probably be widely studied in different species, but before its use in each veterinary species, macrolide analytical determination in various biological fluids is a pre-requisite step for the rational dose calculation of TV based on specific pharmacokinetic information. Its quantification is essential for detecting and avoiding the appearance of residues in animal products intended for human consumption. Therefore, a robust chromatographic method coupled with an ultraviolet detector was fully validated for the quantification of TV in pig plasma. A mixture (78:22) of (A) 0.3% formic acid in water and (B) acetonitrile was used as the mobile phase. TV and enrofloxacin (internal standard) were eluted at 14.1 and 5.9 min, respectively. Calibration curves ranged from 0.1 to 5 μg/mL. The accuracy and precision parameters for the quality controls were always <13.0%. Recovery ranged from 89.66 to 96.92%. The detection and quantification limits were found to be 0.05 μg/mL and 0.1 μg/mL, respectively. This method could be applied to develop pharmacokinetic studies.

A novel liquid chromatography-fluorescence method for the determination of delafloxacin in human plasma

Delafloxacin is a novel fluoroquinolone antibiotic that was approved by the European Medicine Agency to treat bacterial infections of the skin and underlying tissues, and community-acquired pneumonia. Despite being in the market since 2019 in the European Union, there is no published liquid chromatography-fluorescence method for delafloxacin quantification in biological samples. A novel, rapid, and sensitive high-performance liquid chromatographic method was developed to determine delafloxacin in human plasma using its native fluorescence. Plasma delafloxacin concentrations were determined by reverse-phase chromatography with fluorescence detection at 405/450 nm of excitation/emission wavelengths. Delafloxacin was separated on a Kromasil C18 column 250 × 4.6 mm id, 5 µm using isocratic elution. The mobile phase was a mixture of 0.05% trifluoroacetic acid/acetonitrile (52/48). Retention times were 5.4 and 11.6 min for delafloxacin and valsartan (internal standard), respectively. Regression calibration curves were linear over the range of 0.1-2.5 µg/mL. The lower limit of detection was 0.05 µg/mL, and the lower limit of quantification was 0.1 µg/mL. Accuracy and precision were always <11%, and the limit of quantification was <16%. Mean recovery was 98.3%. This method can be applied to determine delafloxacin in human plasma and could be useful to perform pharmacokinetic studies.

Two different synchronous spectrofluorimetric approaches for simultaneous determination of febuxostat and ibuprofen

Two green, simple and sensitive synchronous spectrofluorimetric methods were developed for the first time for the simultaneous estimation of febuxostat (FEB) and ibuprofen (IBU). Method I is constant-wavelength synchronous spectrofluorimetry where FEB and IBU were recorded at 329 and 258 nm, respectively, using Δλ of 40 nm. Method II is constant-energy synchronous spectrofluorimetry using a wavenumber interval of -4000 cm-1. All measurements were carried out in a borate buffer of pH 7 and distilled water for dilution which increased the methods' greenness. The two methods were rectilinear over concentration ranges of 30.0-700.0 ng ml-1 and 0.5-9.0 µg ml-1 in the first method and 20.0-500.0 ng ml-1 and 0.1-8.0 µg ml-1 in the second method for FEB and IBU, respectively. High sensitivity was attained for the two drugs with limits of quantitations (LODs) down to 0.41 and 5.51 ng ml-1 in the first method and 0.25 and 3.32 ng ml-1 in the second method for FEB and IBU, respectively. Recovery percentages were in the range of 97.3-101.9% after extraction from spiked human plasma samples, demonstrating high bioanalytical applicability. The two methods were further applied to tablet dosage forms with good recovery results. The methods' greenness was assessed according to the analytical Eco-Scale and Green Analytical Procedure Index guidelines.