Sustainable Liquid Chromatographic Determination and Purity Assessment of a Possible Add-on Triple-Action Over-the-counter Pharmaceutical Combination in COVID-19

Nowadays, all researchers are focused on combating the pandemic COVID-19. According to recent statistics, most patients are managed at home. An over-the-counter (OTC) triple action formula containing paracetamol (PAR), aspirin (ASP), and diphenhydramine (DIPH) is widely prescribed for pain, fever and as night-time sleep aid. For COVID-19 patients, this combination is now suggested as part of symptomatic therapy and prophylaxis. In this work, two simple liquid chromatographic approaches were designed for simultaneous determination of PAR, ASP, and DIPH in Excedrin® PM caplets, beside three specified official toxic impurities, namely, p-aminophenol, p-nitrophenol, and salicylic acid. The first method comprised high-performance thin-layer chromatographic separation coupled with densitometric quantification, on silica gel HPTLC 60 F₂₅₄ aluminium sheets as the stationary phase, ethyl acetate–methanol-aqueous ammonium hydroxide (10.0: 2.0: 0.1, by volume) as the developing system and scanning was performed at 210.0 nm. The second one is a high-performance liquid chromatography coupled with diode array detector. Successful separation of the six components was performed on XTerra C₁₈ column with isocratic elution of mobile phase 0.1% triethylamine acidified water: methanol (70:30, v/v) adjusted with o-phosphoric acid to pH 3.0 and methanol (90:10, v/v) with flow rate programming and detection at 210.0 nm. Validation of the proposed methods was performed according to ICH guidelines. Both methods were successfully used for quality control of the cited drugs in their marketed formulation. Moreover, the in-vitro release study was monitored using the proposed HPLC-DAD method. The greenness profile of the proposed methods was assessed and comparatively evaluated through various assessment tools, specifically; the analytical eco-scale system, national environmental method index (NEMI), green analytical procedure index (GAPI) and analytical greenness (AGREE) metric.

An Overview of Advances in the Chromatography of Drugs Impurity Profiling

A systematic literature survey published in several journals of pharmaceutical chemistry and of chromatography used to analyze impurities for most of the drugs that have been reviewed. This article covers the period from 2016 to 2020, in which almost of chromatographic techniques have been used for drug impurity analysis. These chromatography techniques are important in the analysis and description of drug impurities. Moreover, some recent developments in forced impurity profiling have been discussed, such as buffer solutions, mobile phase, columns, elution modes, and detectors are highlighted in drugs used for the study. This primarily focuses on thorough updating of different analytical methods which include hyphenated techniques for detecting and quantifying impurity and degradation levels in various pharmaceutical matrices.

Determination of progesterone (steroid drug) in the semi-solid dosage form (vaginal gel) using a stability-indicating method by RP-HPLC/PDA detector

A simple stability-indicating method was developed and validated for the determination of progesterone (a steroid drug) in the semi-solid dosage form. All the impurities were separated from the main compound with a simple stationary phase (Eclipse XDB, C8, 150 × 4.6 mm, 5 μm). The mobile phase A contained phosphate buffer and acetonitrile in the ratio of 90:10, v/v, and mobile phase B contained purified water and acetonitrile in the ratio of 10:90, v/v. The optimized chromatographic conditions were as follows: flow rate, 1.0 mL min^-1 ; UV detection, 241 nm; injection volume, 10 μL; and the column temperature, 30°C. The method was validated as per the current ICH Q2 guidelines. The recovery study and linearity ranges were established from 50 to 300% optimal concentrations. The method validation results were found between 98 and 102% for accuracy and r²  = 0.999 for linearity. Forced degradation in hydrolytic, oxidative, thermolytic, and photostability conditions was performed, and the stability indicating nature of the method was proved. Based on the validation and forced degradation results, the current method was found to be specific, precise, accurate, linear, robust, and stability-indicating method. The developed method was cost effective and easy to handle for quality control analysis.

A rapid RP-HPLC stability-indicating method development and validation of moxifloxacin hydrochloride-related substances in finished dosage forms

A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the identification and quantification of moxifloxacin hydrochloride-related substances in finished dosage forms. Chromatographic separation was achieved on an Agilent C18 column (150 × 4.6 mm, 5 μm) with the mobile phase (0.01 M potassium dihydrogen orthophosphate as buffer and methanol in the ratio of 70:30) eluted in isocratic mode. The HPLC flow rate was 1.0 mL min^-1 , and peaks were monitored at 230 nm using a photodiode array (PDA) detector. The column temperature was kept constant at 30°C, and the injection volume was 10 μL. The run time of the method was 16 min. The method was validated as per the International Conference on Harmonization (ICH) guidelines. Linearity was recorded at various concentrations ranging from 0.25 to 1.5 μg mL^-1 for all the moxifloxacin impurities. Linearity, regression value, recovery, %relative standard deviation (RSD) of method precision values were found within the acceptance limits. The method for related substances (RS) in moxifloxacin was found to be specific, linear, accurate, precise, rugged, and robust. The validated method was suitable for the quantification of the RSs in moxifloxacin drug products. The method was applied in quality control lab for the analysis of moxifloxacin impurities in stability analysis.

Choices of chromatographic methods as stability indicating assays for pharmaceutical products: A review

Stability indicating assay describes a technique which is used to analyse the stability of drug substance or active pharmaceutical ingredient (API) in bulk drug and pharmaceutical products. Stability indicating assay must be properly validated as per ICH guidelines. The important components in a stability indicating assay include sensitivity, specificity, accuracy, reliability, reproducibility and robustness. A validated assay is able to measure the concentration changes of drug substance/API with time and make reliable estimation of the quantity of the degradation impurities. The drug substance is separated and resolved from the impurities. Pros and cons of HPLC, GC, HPTLC, CE and SFC were discussed and reviewed. Stability indicating assay may consist of the combination of chromatographic separation and spectroscopic detection techniques. Hyphenated system could demonstrate parallel quantitative and qualitative analysis of drug substances and impurities. Examples are HPLC-DAD, HPLC-FL, GC-MS, LC-MS and LC-NMR. The analytes in the samples are separated in the chromatography while the impurities are chemically characterised by the spectroscopy in the system. In this review, various chromatographic methods which had been employed as stability indicating assays for drug substance and pharmaceutical formulation were systematically reviewed, and the application of hyphenated techniques in impurities characterisation and identification were also discussed with supporting literatures.

Analytical Quality by Design Approach of Reverse-Phase High-Performance Liquid Chromatography of Atorvastatin: Method Development, Optimization, Validation, and the Stability-Indicated Method

The use of analytical quality by design (AQbD) approach in the optimization of the high-performance liquid chromatography (RP-HPLC) method is a novel tool. Three factors and three levels of Box–Behnken statistical design (BBD) were used for method optimization and analysis of atorvastatin. The mobile phase (acetonitrile: water), flow rate (Rt), and UV wavelength were used as independent variables. Their effects were observed in the area of the chromatogram (AU), retention time (Rt, min), and tailing factor (%). The optimized HPLC condition was found as acetonitrile:water (50 : 50), flow rate (0.68 ml/min), and UV wave length (235 nm). It gives the retention time of 2.43 min with the linearity range of 5–30 μg/ml with a high regression value (r² = 0.999). The method was found to be precise and accurate with low % RSD (<5%). The refrigeration stability indicated that atorvastatin was stable. The force degradation study showed that the atorvastatin was fully unstable in UV light and stable in 0.1 M basic condition. It concluded that this QbD optimized method is suitable for quantification of the atorvastatin from the formulation as well as pharmacokinetic parameters.

Low-level determination of 4-chlorobutyl-(S)-[4-chloro-2-(4-cyclopropyl-1,1,1-trifluoro-2-hydroxy-but-3yn-2-yl)phenyl] carbamate (4-CTHC) in efavirenz drug substance by LC-MS

A rapid, simple, sensitive, and selective liquid chromatography-tandem mass spectrometry (LC-MS) test method was developed and validated for the trace level determination of 4-chlorobutyl-(S)-[4-chloro-2-(4-cyclopropyl-1,1,1-trifluoro-2-hydroxy-but-3yn-2-yl)phenyl] carbamate (4-CTHC). 4-CTHC is a potential genotoxic impurity in efavirenz drug substance and the acceptable level is 2.5 μg ml^-1 with respect to analyte concentration according to ICH M7(R1) Multidisciplinary Guidelines M7(R1). The LC-MS/MS analysis of 4-CTHC impurity was carried out on a Kinetex C₁₈ (150 × 4.6 mm, 5.0 μm) column. In this test procedure, the mobile phase was prepared with buffer (0.1% formic acid in water) and acetonitrile in the ratio of 1:3 (v/v). The method set flow rate was 0.4 ml min^-1 . The method was developed with a short run time of <10 min. Selective ion monitoring acquisition mode and negative polarity electrospray ionization mode were used as an MS method to quantify genotoxic impurities at 422.25 Da. The method showed linearity in a range of 0.64-3.71 μg ml^-1 with a correlation coefficient of 0.9992. The RSD for intra-day and inter-day precision was found to be <5%. The method's accuracy was in the range of 106.5-112.4% for the genotoxic impurity of 4-CTHC. The procedure was validated as per the current ICH Q2 (R1) guidelines and proved suitable for stability testing in the quality control laboratory for pharmaceutical preparations.

Stability-indicating ultra performance liquid chromatography method development and validation for simultaneous estimation of metformin, linagliptin, and empagliflozin in bulk and pharmaceutical dosage form

A rapid stability-indicating reversed phase-ultrapure liquid chromatography (RP-UPLC) was developed and validated for the estimation of metformin (MET), linagliptin (LIN), and empagliflozin (EMP) combination in bulk and tablet dosage form using Kromasil C₁₈ column (2.1 × 50 mm, 1.8 μm) as a stationary phase and a mixture solution of 40% phosphate buffer (pH = 3) and 60% acetonitrile as mobile phase at a flow rate of 0.6 mL/min. The detection was performed at 248 nm using a photodiode array detector. The linearity, sensitivity, selectivity, robustness, specificity, precision, and accuracy were determined. The peak area response-concentration curve was rectilinear over the range of 50-150 (MET), 5-15 (LIN), and 10-30 μg/mL (EMP) with quantitation limits of 0.042 (MET), 0.023 (LIN), and 0.059 μg/mL (EMP). The proposed method was successfully validated for the determination of MET, LIN, and EMP simultaneously in combined tablet dosage form. The performance of the proposed method was compared with reported RP-UPLC methods and found to be rapid and economical. The developed and validated stability-indicating RP-UPLC method was appropriate for the quality control and drug analysis.

Green analysis of newly approved binary omeprazole/aspirin mixture in presence of aspirin impurity using ultra-high-performance liquid chromatography and thin-layer chromatography methods

Two green, simple, and accurate chromatographic methods were developed and validated for the simultaneous determination of omeprazole and aspirin mixture in the presence of salicylic acid, a major impurity of aspirin. Method A is a reversed-phase ultra-high-performance liquid chromatography; the separation was performed on a C18 column, with a mobile phase composed of ethanol:0.1% aqueous solution of triethylamine acidified with orthophosphoric acid (pH 3) (30:70, v/v) at 0.15 mL/min flow rate and 230 nm. Omeprazole, aspirin, and aspirin impurity retention times were 7.47, 4.40, and 5.13 min, respectively. Good linearity was achieved in the concentration ranges of 5-80, 5-85, and 3-50 μg/mL for the three mentioned components, respectively. Method B is thin-layer chromatography (TLC) where silica gel TLC F254 plates were utilized to achieve separation using ethanol:ethyl acetate (2:8, v/v) as a developing system at 240 nm. The resulted R_f values were 0.83, 0.65, and 0.23 for omeprazole, aspirin, and impurity, respectively. The concentration ranges of 0.1-3 μg/band for the three drugs showed good linearity. The proposed methods are eco-friendly and greener when compared to the already reported method (Microchemical Journal, 152, 104350). This is the first use of TLC method for the determination of the three drugs. International Council for Harmonization (ICH) guidelines were followed to ensure the validity of developed methods.

QbD based development of HPLC method for simultaneous quantification of Telmisartan and Hydrochlorothiazide impurities in tablets dosage form

A simple reverse phase liquid chromatographic gradient method has been developed and validated for the simultaneous determination of specified & un-specified impurities of Telmisartan and Hydrochlorothiazide in combination oral solid dosage forms. The developed method is effective to separate a total of sixteen (16) peaks and quantify eleven (11) specified impurities of Telmisartan and three (3) specified impurities of Hydrochlorothiazide with a minimum chromatographic resolution of 2.5. The separation was acquired with Inertsil ODS-3V, 150 ​× ​4.6 ​mm, 3.5 ​μm column at a flow rate of 1.0 mL min^-1 with the mobile phase-A consists of 0.02 ​M potassium dihydrogen phosphate (pH of 3.5) and mobile phase-B consists of a mixture of Milli-Q water and acetonitrile (100: 900 v/v) respectively. The detection of impurities was carried out at 230 ​nm and column temperature was maintained at 40 ​°C. Further optimized chromatographic conditions were applied to design of experiments to find out the critical quality attributes and established the design space. The binary combination of drug product was subjected to the different stress conditions such as acid, base, oxidation, heat and photolysis as per the recommendations of international conference on harmonization (Q2). The degradation Product found in stress patterns are well separated among main analyte compounds. The method was validated to be specific, robust and rugged in terms of change of chromatographic, instrumental and technical variables.

A novel RP-HPLC refractive index detector method development and validation for determination of trace-level alcohols (un-sulfated) in sodium lauryl sulfate raw material

The main aim of the study is to develop and validate a simple and rapid liquid chromatographic analytical method for simultaneous determination of trace level of un-sulfated alcohol impurities in sodium lauryl sulfate using high-performance liquid chromatography with a refractive index detector. The chromatographic separation was achieved using flow rate of 3.0 ml/min with a Waters Symmetry C₁₈ (150 × 4.6 mm, 5 μm) column and 50°C as a column temperature. The mobile phase comprised milliQ water and acetonitrile in the ratio of 30:70 v/v respectively. The detection was performed using a refractive index detector at a sensitivity of 64. The resolutions among n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, and n-heptadecanol were found to be >4. Regression analysis showed a correlation coefficient for the stated compounds of >0.999. The validated HPLC method was utilized effectively for the estimation of un-sulfated alcohols in quality control labs for commercial release of sodium lauryl sulfate.