Green HPLC Method for Simultaneous Analysis of Three Natural Antioxidants by Analytical Quality by Design

BACKGROUND

Glutathione, silybin, and curcumin are well-known potential antioxidants that are recommended as adjuvant therapy in cancer treatment.

OBJECTIVE

Based on the principles of Analytical Quality by Design (AQbD) and green analytical chemistry, a simple, robust, and environmentally benign HPLC method for the simultaneous estimation of glutathione, silybin, and curcumin in bulk and formulation was performed.

METHOD

Elution was achieved by an Agilent Eclipse XDB C18 (150 mm × 4.6 mm id, 3.5 μm) column using a gradient mobile phase composed of ethanol-water pH 6.7 (with 0.1%, v/v orthophosphoric acid) and 1.07 mL/min flow rate with PDA detection at 215 nm. Critical method variables were identified by risk assessment using an Ishikawa diagram, and multivariate optimization of the experimental conditions for the HPLC technique was accomplished by central composite design using design of experiments (DoE) software.

RESULTS

The separation was achieved within 15 min, where the retention time of glutathione, silybin, and curcumin were 3.3, 4.9, and 7.3 min, respectively. The standard curve was linear in the range of 3.75-26.25 µg/mL for glutathione, 62.50-437.50 µg/mL for silybin, and 12.5-87.50 µg/mL for curcumin. The developed method was validated as per ICH guidelines Q2 (R1), and all the parameters are within specified limits.

CONCLUSIONS

The proposed method is simple, precise, and robust, which can be employed for routine analysis and also concluded to be a greener approach according to AGREE, Green Analytical Procedure Index, and analytical eco-scale tools.

HIGHLIGHTS

The chosen antioxidants were evaluated for the very first time simultaneously using the chromatographic technique in bulk and dosage forms employing green solvents. The peak purity of all three compounds was studied using a PDA detector. Wastage was reduced in terms of time, cost, and solvents by employing AQbD elements and tools. Complete application of environmentally sustainable safe solvents were employed.

Characterization, quantification and a multi-computational in silico toxicity assessment of impurity (feruloyl methane) in synthetic curcumin using RP-HPLC-UV technique

Feruloyl Methane (FM) is a common impurity in Synthetic Curcumin (SC) that affects its purity and potency. The identification and quantification of FM is crucial to ensure the quality and safety of SC based drugs. The current study aims to develop and validate a simple, rapid and cost-effective analytical technique for the precise and accurate quantification of FM in SC using RP-HPLC with a UV-Vis detector (Ultraviolet/Visible) and assessment of its toxicity by multi-computational methods. The developed HPLC method with a UV-Vis detector enabled accurate identification and quantification of FM in SC. The optimized method was validated in accordance with ICH guidelines Q2(R1) and all parameters were found to be within the standard acceptance range. The ideal run time was determined to be 10 min and the impurity eluting at a retention time of 2.65 min was characterized using spectral techniques viz., mass spectrometry, FTIR and 1 H NMR, confirming the presence of FM. The amount of FM in SC was estimated to be 8.26 µg/kg. In addition, toxicity assessments using in silico tools such as ProTox- II, ADMETlab 2.0 and PASS Online indicated that the presence of FM in SC is not safe for human consumption. In conclusion, the developed method is not only capable of quantifying FM but also aids in distinguishing Natural Curcumin (NC) adulterated with SC and can be applied to a wide range of fields such as natural drug analysis, food analysis and toxicity prediction.

Nitrosamine Impurities in Herbal Formulations: A Review of Risks and Mitigation Strategies

Nitrosamines are a class of chemical compounds that have been found to be impurities in a variety of pharmaceutical products. These impurities have raised concerns due to their potential carcinogenic effects. Recent studies have identified nitrosamines as impurities in a number of pharmaceutical products including angiotensin II receptor blockers (ARBs) and proton pump inhibitors (PPIs). The presence of nitrosamines in these products has led to recalls and market withdrawals. In addition to pharmaceuticals, nitrosamines have also been found in some herbal medicines particularly those containing traditional Chinese medicinal ingredients. The presence of nitrosamines in herbal formulations poses a significant risk to public health and highlights the need for quality control and regulations in the herbal drug industry. The present review article aims to discuss nitrosamine impurities (NMI) prominent causes, risks and scientific strategies for preventing NMI in herbal formulations. The primary objective of this study is to examine the origins of nitrosamine contamination in herbal formulations, the risks associated with these contaminants, and the methods for reducing them. The significance of thorough testing and examination before releasing herbal products to the public is also emphasized. In conclusion, the presence of nitrosamines is not limited to pharmaceutical products and poses a significant threat to the safety of herbal drugs as well. Adequate testing and extensive research are crucial for producing and distributing herbal medicines to the general population.

RESPONSE SURFACE METHODOLOGY ASSISTED ULTRAPERFORMANCE LIQUID CHROMATOGRAPHIC METHOD OPTIMIZATION FOR THE SIMULTANEOUS ESTIMATION OF SIX FAT-SOLUBLE VITAMINS IN TABLET DOSAGE FORM USING A DEVELOPED AND VALIDATED UPLC-Q-TOF/MS METHOD

In this study, the liquid chromatographic (LC) parameters were optimized using response surface methodology (RSM) as a novel approach to achieve optimal separation of six vitamers of vitamin D and K during simultaneous estimation. Analytes were separated using an Accucore C18 column (50 x 4.6 mm, 2.6 µm), 0.1% aqueous formic acid (pH = 3.5), and methanol as mobile phase components. The Box-Behnken design (BBD) predicted the best combination of the selected critical quality attributes such as organic solvent composition in the mobile phase (90%), mobile phase flow rate (0.42 mL/min), and column oven temperature (40oC). Multiple regression analysis was used to fit the experimental data from 17 sample runs to a second-order polynomial equation. The adjusted coefficient of determination (R2) for three desired responses were 0.983 (retention time of K3 = R1), 0.988 (resolution between D2 and D3 = R2), and 0.992 (retention time of K2-7 = R3), all with significant probability values (p<0.0001), indicating a high significance for the regression model. Q-ToF/MS detection was interfaced with an electrospray combined ionization source. The optimized detection parameters delivered specific, sensitive, linear, accurate, precise, and robust quantification of all six analytes in the tablet dosage form.

Optimization of ultrasonication-assisted extraction conditions using RSM-I-Optimal experimental design to recover vitamin D2 and K1 from selected green leafy vegetable samples

This study employed the response surface methodology to optimize the extraction conditions for recovering vitamins D₂ and K₁ from green leafy vegetables using ultrasonication-assisted extraction. The vitamin content was determined using an Accucore C18 column and a UPLC-Q-ToF/MS method. An RSM-I-Optimal design was used for designing the experiment to find the best combination of solvent level (mL), sonication time (min), sonication frequency (kHz), and temperature (°C). The experimental data from a 25-sample set were fitted to a second-order polynomial equation using multiple regression analysis. The extraction models had R² values of 0.895 and 0.896, respectively, and the probability values (p < 0.0001) indicated that the regression model was highly significant. The optimal extraction conditions were: solvent level of 65 mL, sonication time of 45 min, sonication frequency of 70 kHz, and temperature of 45 °C. Under these conditions, the predicted recovery (%) values for vitamins D₂ and K₁ were 90.7% and 90.4%, respectively. This study has the potential to use the reported extraction method for routine quantification of vitamins D₂ and K₁ in the laboratory using UPLC-Q-ToF/MS.

Ultra-Performance Liquid Chromatography Coupled with a Triple Quadrupole Mass Spectrometric Method for the Quantification of Antiepileptic Drugs Methsuximide and Normesuximide in Human Plasma and its Application in a Pharmacokinetic Study

Background:

Extensive therapeutic drug monitoring needs an analytical method for efficient and sensitive quantification of analytes of interest in clinical pharmacology.

Objective:

A rapid, robust, sensitive and simple UPLC-MS/MS method to quantify Methsuximide (Ms) and N-desmethyl methsuximide/Normesuximide (MsMET) in human plasma was optimized, developed, and validated for application in a pharmacokinetic study.

Method:

Reverse phased chromatography was performed using Zorbax SB-C18, 4.6 x 75 mm., 3.5 μm as stationary phase, methanol and 0.1% formic acid (60:40 v/v) as mobile phase which was delivered isocratically at a flow rate of 0.9 mL/min. The sample injection volume was 5 μL. Mass spectrometric quantification of the analytes was performed using positive electrospray ionization as mass interface along with multiple reaction monitoring (MRM) as acquisition mode.

Results:

The selected mass transition ions for analyte, metabolite and its respective internal standards are as follows, precursor ion (m/z) and product ion (m/z): Ms (204.06 and 119.02), MsMET (190.05 and 119.82), Ms internal standard (MsIS) (209.17 and 124.02), and MsMET internal standard (MsMETIS) (195.09 and 124.16), respectively. The current method was found to be linear for Ms (60.720-6043.800 ng/mL) and MsMET (60.389 - 6010.800 ng/mL) with r2 values not less than 0.999. The mean recoveries of all analytes ranged between 71.37 and 86.38 percentage. Conclusion: This method was validated in accordance with USFDA’s bioanalytical guidelines.

Conclusion:

This method was validated in accordance with USFDA’s bioanalytical guidelines. This method could be applied for a routine analysis of Ms and MsMET in clinical pharmacological practice.

Quantification of rosiglitazone in rat plasma and tissues via LC-MS/MS - method development, validation, and its application in pharmacokinetic and tissue distribution studies

A bioanalytical method for the quantification of rosiglitazone on rat plasma and tissues (adipose tissue, heart, brain, bone, and kidney) using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated. Chromatographic separation was achieved on Gemini C₁₈ column (50mm x 4.6mm, 3μm) using mobile phase consists of 10mM ammonium formate (pH 4.0) and acetonitrile (10:90, v/v) at a flow rate of 0.8 mL/min and injection volume of 10μL (Internal standard - Pioglitazone). LC-MS detection was performed with multiple reaction monitoring mode (MRM) using target ions at m/z→358.0 and m/z → 357.67 for rosiglitazone and pioglitazone (IS) respectively. The calibration curve showed a good correlation coefficient (r² ) over the concentration range of 1-10000 ng/mL. The mean percentage recoveries of rosiglitazone were found to be over the range of 92.54-96.64 % with detection and lower quantification limit of 0.6 ng/mL and 1.0 ng/mL, respectively. The developed method was validated as per USFDA guidelines and successfully utilized to measure rosiglitazone in plasma and tissue samples. Further, the developed method can be utilized for validating specific organ targeting delivery systems of rosiglitazone in addition to conventional dosage forms.

Beta-Alanine and Tris-(hydroxyl methyl) Aminomethane as Peak Modifiers in the Development of RP-HPLC Methods Using Aceclofenac and Haloperidol Hydrochloride as Exemplar Drugs

In the present analytical approach, beta-alanine (ALA) and tris-(hydroxyl methyl) aminomethane (TRIS) were investigated as peak modifiers due to their water solubility and their possible peak modifying a property. These reagents were tested for their efficacy on the elution of aceclofenac (ACF) and haloperidol hydrochloride (HLC) from C18 column (250 mm × 4.6 mm, 5 μ) equipped with a photodiode array detector. The test reagents were investigated at 0.25 ± 0.05% concentration with a varying % aqueous composition on elution efficacy of HLC and ACF. The added ALA/TRIS in the mobile phase significantly (P < 0.05) improvised the symmetrical elution of HLC with 3-fold theoretical plates increase (P < 0.05) and 10-fold reduced capacity factor as compared to the control run. For ACF, the shoulder effect observed for ACF peak was eliminated. The optimized mobile phase was a combination of acetonitrile and water containing 0.25% beta-alanine/TRIS (pH 3.5 with ortho-phosphoric acid) at the ratio of 70:30 and 60:40% v/v, respectively, for ACF and HLC. The method was validated as per ICHQ2 guidelines. The column performance was tested for reproducibility in non-peak modifier applications and revealed a null effect on the column, thus these agents are relatively less toxic to HPLC columns.

Simultaneous Quantification of Pantoprazole and Levosulpiride in Spiked Human Plasma Using High Performance Liquid Chromatography Tandem Mass Spectrometry

Background:

Pantoprazole (PTZ) and Levosulpiride (LS) were proven as effective agents for the treatment of Gastro-Esophageal Reflux Disease (GERD). It is a complex motor disorder that results in regurgitation of the gastric contents into the lower esophagus with consequent symptoms such as heart burn, retrosternal pain, dysphagia and belching.

Methods:

A rapid, sensitive, selective and specific liquid chromatography- electro spray ionization tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantification of Pantoprazole (PTZ) and Levosulpiride (LS) in spiked Human Plasma. The method utilized SPE as sample preparation technique and the analysis was carried out on a HPLC system utilizing electro spray ionization as interface and triple quadrupole mass analyzer for quantification in MRM possitive mode. Iloperidone was used as internal standard (IS). Chromatographic separation was performed on a Phenomenex C-18 Column (4.6 mm x 50 mm, 5µ) with an isocratic elution mode utilizing a mobile phase composition of Solution containing a mixture of 70 volumes of acetonitrile: 30 volumes of methanol and 10mM ammonium formate (pH 4.0) at the ratio of 80:20 % v/v. The flow rate was maintained at 0.3 mL/min.

Results:

PTZ, LS and IS were detected and quantified with proton adducts at m/z 383.37→200.00, m/z 341.42→112.15 and 426.48→261.00 respectively. The linearity and range was established by fortifying blank plasma samples in the concentration range of 3.5-2000 ng/mL for PTZ and 3.0-2400 ng/mL for LS. The correlation coefficient (r2) was found to be ≥ 0.993 for PTZ and (r2) ≥ 0.990 for LS. The lower limit of quantification for PTZ was 3.5 ng/mL and LS was 3.0 ng/mL. The intra and inter day precision and accuracy for PTZ and LS were within the limits fulfilling the international acceptance criteria. PTZ and LS were found to be stable throughout three freeze-thaw cycles, bench top and short term stability studies.

Conclusion:

The proposed validated LC-MS/MS method offers a sensitive quantification of PTZ and LS in spiked human plasma and can be utilized for the quantification of PTZ and LS in real-time samples.

Characterization of the Oxidative Degradation Product of Darunavir by LC-MS/MS

A rapid, selective, and reliable LC-MSⁿ method has been developed and validated for the isolation and structural characterization of the degradation product of darunavir (DRV). DRV, an HIV-1 protease inhibitor, was subjected to intrinsic oxidative stress conditions using 30% hydrogen peroxide and the degradation profile was studied. The oxidative degradation of DRV resulted in one degradation product. The unknown degradation product was separated on a Hibar Purospher C₁₈ (250 mm × 4.6 mm; 5 µm) column by using 0.01 M ammonium formate (pH 3.0) and acetonitrile as mobile phase in the ratio of 50:50, v/v. The eluents were monitored at 263 nm using a UV detector. The isolated degradation product was characterized by UPLC-Q-TOF and its fragmentation pathway was proposed. The proposed structure of the degradation product was confirmed by HRMS analysis. The developed stability-indicating LC method was validated with respect to accuracy, precision, specificity/selectivity, and linearity. No prior reports were found in the literature about the oxidative degradation behavior of DRV.