Development, optimisation and validation of a stability-indicating HPLC method of achyrobichalcone quantification using experimental designs

Achyrocline satureioides as an adjuvant therapy for the management of mild viral respiratory infections in the context of COVID-19: Preliminary results of a randomized, placebo-controlled, and open-label clinical trial

We evaluated the impact of an Achyrocline satureioides inflorescence infusion on the clinical outcomes of viral respiratory infections, including those caused by SARS-CoV-2, in a monocentric, randomized, open-label, placebo-controlled clinical trial. Patients with symptoms of viral respiratory infection, including suspected cases of COVID-19, were included and assigned to receive either A. satureioides (n = 57) or Malus domestica (n = 67) infusions twice a day for 14 days. All participants were included before the RT-PCR results, performed using a nasopharyngeal swab. The patients were further divided into subgroups according to real-time polymerase chain reaction results: SARS-CoV-2-positive and SARS-CoV-2-negative subgroups for statistical analyses. We assessed clinical outcomes, such as the latency to resolution of cough, dyspnea, fever, sore throat, chest pain, smell and taste dysfunctions, diarrhea, nausea, abdominal pain, and loss of appetite; hospitalization; and mortality with questionnaires and medical records. The subjects that received early A. satureioides infusion showed a significant reduction in the average number of days with respiratory and neurological symptoms compared with the control group (M. domestica infusion). We conclude that A. satureioides is a safe agent and, in combination with standard care, improves viral respiratory infection symptoms, especially those related to COVID-19.

Proceedings of Chemistry, Pharmacology, Pharmacokinetics and Synthesis of Biflavonoids

Biflavonoids, composed of two monoflavonoid residues, occur naturally in angiosperms, bryophytes, ferns, and gymnosperms. More than 592 biflavonoids have been structurally elucidated, and they can be classified into two groups of C-C and C-linear fragments-C, based on whether the linker between the two residues contains an atom. As the linker can be established on two arbitrary rings from different residues, the C-C type contains various subtypes, as does the C-linear fragment-C type. Biflavonoids have a wide range of pharmacological activities, including anti-inflammatory, antioxidant, antibacterial, antiviral, antidiabetic, antitumor, and cytotoxic properties, and they can be applied in Alzheimer's disease and Parkinson's disease. This review mainly summarizes the distribution and chemistry of biflavonoids; additionally, their bioactivities, pharmacokinetics, and synthesis are discussed.

Design of Experiment (DoE)-Approach Based RP-HPLC Analytical Method Development and Validation for Estimation of Efavirenz in Bulk and Formulations

Present study reports design of experiment (DoE) based development and validation of a simple, rapid and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method for estimation of efavirenz (EFZ), a non-nucleotide reverse transcriptase inhibitor (NNRTs), used in the treatment of acquired immunodeficiency syndrome (AIDS). Plackett-Burman design was explored to screen the critical method variables (CMVs) for the RP-HPLC method. A response surface Box-Behnken design was employed to optimize the screened CMVs which affect the analytical responses (ARs) of RP-HPLC method. Using the optimized CMVs the HPLC method was developed and validated according to International Conference on Harmonization (ICH) guidelines. EFZ in marketed formulation was estimated using the validated method. Acetonitrile proportion, pH of the phosphate buffer and mobile phase flow rate were the CMVs and retention time and number of theoretical plates were the ARs for the study. The optimized chromatographic parameters were acetonitrile proportion in mobile phase: 51.17%v/v, pH of phosphate buffer: 4.04 and flow rate: 1.25 mL/min. Use of these optimized parameters resulted in retention time of 11.031 min and 9,498.787 number of theoretical plates as ARs of the HPLC method. The method was further validated in harmony with current ICH guidelines Q2 (R1). The method was capable of the successful estimation of EFZ in marketed formulation. The study depicts successful development and validation of a simple RP-HPLC method of EFZ using DoE approach.

Formulation and evaluation of anti-MRSA nanoemulsion loaded with Achyrocline satureioides: a new sustainable strategy for the bovine mastitis

Methicillin-resistant Staphylococcus aureus (MRSA) causes mastitis in dairy cattle with serious economic and public health significance. This study developed nanoemulsions of Linum usitatissimun oil loaded with Achyrocline satureioides (macela) extract and investigated their in vitro antimicrobial activity against MRSA. Macela-nanoemulsions (NE-ML) were prepared using high-pressure homogenization (HPH) with different proportions of flaxseed oil, Tween 80 and crude extract. Four majoritarian flavonoids were identified in the macela extract: 3-O methylquercetin, achyrobichalcone, quercetin and luteolin (187.3 ± 0.1, 155.4 ± 11.6, 76.3 ± 0.1 and 30.4 ± 0.0 μg ml−1, respectively). NE-ML nanoemulsions were successfully obtained by the HPH method and showed a milky aspect with yellowish color. The mean particle size was around 200 nm with monodisperse distribution (PdI < 0.2), remaining stable for 160 days at room temperature. When analyzed on a LUMiSizer high-end dispersion analyzer, low values were found (≤0.5), indicating high stability index, mainly for NE-ML1:5 (0.2). The encapsulation efficiency of macela-nanoemulsions was greater than 94%, considering the four chemical compounds from extract. Minimum inhibitory concentration (MIC) against planktonic bacteria, inhibition of biofilm formation (MBIC), and eradication of MRSA biofilms (MBEC) were determined through in vitro tests on microplates. The MIC of NE-ML against planktonic MRSA showed values ranging from 1.2 to 10% (v/v), while blank-nanoemulsions (NE-B, without macela extract) showed values ranging from 6 to 50% (v/v). MBIC and MBEC of NE-ML were 25 and 80% (v/v), respectively. MBIC showed a mass reduction greater than 64%, and MBEC showed a mass reduction greater than 73%. Macela-nanoemulsions (NE-ML), mainly NE-ML1:5, showed high antimicrobial activity and appeared to represent a new alternative of sustainable antimicrobial product for the control of MRSA. Since this innovative nanoemulsion can impact animal health, future research should include in vitro and in vivo studies to evaluate intramammary therapy and control of MRSA infections in organic and agroecological milk production systems.

Enantioselective Box Behenken Optimized HPLC-DAD Method for the Simultaneous Estimation of Alogliptin Enantiomorphs in Pharmaceutical Formulations and their Pharmacokinetic Study in Rat Plasma

Purpose: A stereoselective high performance liquid chromatographic analytical method with photodiode array detector was developed and validated as per the International Conference on Harmonization (ICH) guidelines for the determination of alogliptin (ALO) enantiomers in formulations and rat plasma.

Methods: Enantiomeric separation was performed on a Phenomenex Lux Cellulose-2 chiral column. Box-Behnken design was used to identify the optimum conditions of the three independent variables for the desired output responses.

Results: The HPLC peaks of ALO enantiomers and the internal standard pioglitazone were achieved before 8 min with a resolution of 0.77 min between R and S enantiomer and resolution of more than 2.0 between each enantiomer and pioglitazone (internal) with more than 95% recovery. The linearity range and the limit of quantification of both the enantiomers in rat plasma were 10-70 ng mL^-1 and 1.2 ng mL^-1 respectively.

Conclusion: The developed method after validation was successfully applied for estimation of ALO enantiomers in formulations. Single oral dose of 25 mg of the ALO racemate tablets were administered to a group of 6 healthy rats for a comparative pharmacokinetic study of both the enantiomers.

Semi-preparative isolation and purification of phenolic compounds from Achyrocline satureioides (Lam) D.C. by high-performance counter-current chromatography

INTRODUCTION

Phenolic compounds present in Achyrocline satureioides are known to have therapeutic benefits like antioxidant, anti-inflammatory, and antitumour properties. The main polyphenols present in the plant are quercetin (QCT), luteolin (LUT), 3-O-methylquercetin (3OMQ), and achyrobichalcone (ACB). However, the effective isolation and purification of these compounds from A. satureioides inflorescences are not an easy task.

OBJECTIVE

To develop an efficient high-performance counter-current chromatography (HPCCC) method for quick separation and purification of naturally occurring phenolic compounds from the extract of A. satureioides.

METHODOLOGY

A two-step HPCCC semi-preparative isolation method was developed using a solvent system composed of n-hexane/ethyl acetate/methanol/water (0.8:1.0:0.8:1.0) and dichloromethane/methanol/water (3.5:3.5:2.5).

RESULTS

The HPCCC method was used to obtain two fractions. The first fraction (F₁ ) contained high levels of ACB, among other constituents, while the second fraction (F₂ ) contained mostly QCT, LUT, and 3OMQ. Besides the high ACB content, F₁ contained three other flavonoid-aglycones (kaempferol, 97.3%; isokaempferide, 92.4%; and 3,3'-di-O-methylquercetin, 95.2%) identified by an ultra-performance liquid chromatography system coupled to a quadrupole time-of-flight with high-definition mass spectrometry (UPLC-QTOF/HDMS) and nuclear magnetic resonance (NMR) analysis. Purity levels of ACB, 3OMQ, QCT, and LUT were 98.0, 97.0, 97.5, and 90.2%, respectively.

CONCLUSION

This is the first time that high purity ACB and six other flavonoids were obtained from A. satureioides inflorescences by HPCCC. These excellent results reveal the potential and versatility of HPCCC as a technique to produce different types of products from this plant species on a semi-preparative scale: enriched fractions, new metabolites, or high purity compounds.

Application of the Principles of Green Chemistry for the Development of a New and Sensitive Method for Analysis of Ertapenem Sodium by Capillary Electrophoresis

An innovative method is validated for the analysis of ertapenem sodium by capillary electrophoresis using potassium phosphate buffer 10 mM pH 7 and 15 kV voltage, in the concentration range of 70 to 120 μg mL⁻¹. Ertapenem had a migration time of 3.15 minutes and the linearity curve was y = 2281.7 x - 24495 with a R² = 0.9994. Thus, we propose a routine analysis method that meets the principles of green analytical chemistry for the routine analysis of ertapenem sodium by capillary electrophoresis.

Design of experiments-based RP - HPLC bioanalytical method development for estimation of Rufinamide in rat plasma and brain and its application in pharmacokinetic study

This study reports a fully validated HPLC-UV (High Performance Liquid Chromatography- Ultra Violet) method for quantitative estimation of Rufinamide (RUFI), an antiepileptic drug, in rat plasma and brain matrices. A response surface methodology based Box Behnken experimental design, using the principles of Design of Experiments (DoE), was employed to optimize critical chromatographic conditions viz. pH and proportion of the buffer and wavelength of detection, for achieving good sensitivity (peak area) and specificity (number of theoretical plates). A desirability function was employed to identify the optimized conditions, which gave a highest value of 0.971. The optimized chromatographic conditions were: pH of the buffer: 4.7, wavelength of detection: 215 nm and proportion of buffer in mobile phase: 84.7% v/v for responses: 124839.6 mV ∗ min as the peak area (1 μg/mL) and 20,000 as the theoretical plate number for the same. A simple protein precipitation method, using methanol, was employed to extract RUFI from the biological matrices. Piribedil was used as the internal standard (IS). At the optimized conditions, the LOQ values of RUFI in plasma and brain were found to be 13.84 ng/mL and 105.24 ng/g respectively. The developed method was validated as per ICH guidelines and its applicability in analysing RUFI in rat plasma and brain matrices was demonstrated by i.v. administration in rats. The AUC_0-t in plasma was found to be 91.9% of AUC_0-∞ indicating that the method is very sensitive and can capture almost the entire plasma time course of RUFI, at a dose of 0.5 mg/kg.

Validation of an HPLC-UV method for analysis of Kaempferol-loaded nanoemulsion and its application to in vitro and in vivo tests

A simple and reliable HPLC-UV method for Kaempferol (KPF) determination in a Kaempferol-loaded nanoemulsion (KPF-NE), samples from mucosa permeation/retention studies, and murine brain was developed and validated according to international guidelines. The analyses were performed on a reversed-phase C18 column at 35°C and under UV detection at 368nm. The mobile phase was composed of methanol:formic acid 0.1% (75:25, v/v) and was eluted at an isocratic flow rate of 1.0mL/min. The method was selective and sensitive for KPF analysis in matrix extracts, and linear in the range of 0.25-7.5μg/mL. The method was also considered precise, accurate, and robust. The recovery rates of KPF from the porcine nasal mucosa and murine brain were higher than 85%. Low matrix effect was observed to determine KPF, including biological matrices. The applicability of the method was confirmed in all different approaches, i.e., quantification of KPF in nanoemulsion, in vitro permeation/retention of KPF across porcine nasal mucosa, and in vivo quantification of KPF in brain samples after nasal administration in rats. Thus, the method is effective and reliable to determine KPF in different real samples. The proposed method, therefore, provides a useful quantification approach to routine processes, to the development of drug delivery systems, and to KPF quantification in different biological matrices. Furthermore, the method is applicable in bioavailability studies and the developed formulation (KPF-NE) is suitable for preclinical trials in different brain disorders.

An overview of experimental designs in HPLC method development and validation

Chemometric approaches have been increasingly viewed as precious complements to high performance liquid chromatographic practices, since a large number of variables can be simultaneously controlled to achieve the desired separations. Moreover, their applications may efficiently identify and optimize the significant factors to accomplish competent results through limited experimental trials. The present manuscript discusses usefulness of various chemometric approaches in high and ultra performance liquid chromatography for (i) methods development from dissolution studies and sample preparation to detection, considering the progressive substitution of traditional detectors with tandem mass spectrometry instruments and the importance of stability indicating assays (ii) method validation through screening and optimization designs. Choice of appropriate types of experimental designs so as to either screen the most influential factors or optimize the selected factors' combination and the mathematical models in chemometry have been briefly recalled and the advantages of chemometric approaches have been emphasized. The evolution of the design of experiments to the Quality by Design paradigm for method development has been reviewed and the Six Sigma practice as a quality indicator in chromatography has been explained. Chemometric applications and various strategies in chromatographic separations have been described.