European Medicines Agency Guidelines Research Articles

Ten-Year Antimicrobial Resistance Trend in Uropathogenic Escherichia coli (UPEC) Isolated from Dogs and Cats Admitted to a Veterinary Teaching Hospital in Italy

Urinary tract infections (UTIs) are a common occurrence in cats and dogs. Surveillance of antibiotic resistance trends helps in the prudent selection of suitable antimicrobial agents. However, there are limited available data on this matter in Italy. This retrospective study aimed to investigate the trends of antimicrobial resistance in uropathogenic Escherichia coli (UPEC) isolated from cats and dogs over ten years (January 2014 to October 2023). Three hundred thirty-nine UPEC strains were isolated from urine samples submitted to the Veterinary Teaching Hospital of Torino (Italy). Antimicrobial susceptibility testing was conducted for up to 11 classes of antibacterials, categorized into four categories (A, B, C, and D) following the European Medicine Agency guidelines for prudent antimicrobial use in animals. The results reveal a higher resistance towards compounds in categories C and D, while fewer isolates were resistant to antibacterials in categories B and A. Resistance has steadily increased from 2014 to 2019. Starting from 2020, a decline in resistance is evident in all four categories. The reduction is more pronounced for the categories subject to the greatest restrictions under European and national legislation. The change in resistance trend is in line with findings from other European countries and food-production animals in Italy.

Single-dose and steady-state pharmacokinetics of clomipramine, yohimbine and clomipramine/yohimbine combination: A clinical drug-drug interaction study.

Clomipramine (CLOMI) has shown effectiveness in treating premature ejaculation but is linked to erectile dysfunction and reduced libido. Yohimbine (YOH), by contrast, is effective in treating erectile dysfunction and may improve libido. Combining CLOMI and YOH could potentially leverage the benefits of both drugs. This study aimed to investigate the interactions between these drugs and to evaluate their safety profile. A prospective, open-labelled, single-centre, pharmacokinetic (PK) drug-drug interaction study was performed in 15 healthy male subjects. Single-dose and steady-state PK were investigated using noncompartmental analysis after mono- and combination therapy of the 2 orally applied drugs. Plasma sampling was performed at baseline, 0.5 (YOH), 1, 1.5 (YOH), 2, 3, 4, 5, 6, 8, 12 and 24 h (CLOMI). Differences in the area under the curve after multiple dosing (MD) were determined using an equivalence boundary of 80-125%. The geometric mean ratio of the area under the curve up to 12 h for MD CLOMI (combination vs. monotherapy) was 112% (90% confidence interval: 104-120%), whereas for MD YOH this ratio was 137% (90% confidence interval: 112-168%). The study drugs were safe and well tolerated as mono- and combination therapy, with no major adverse events reported. A PK assessment of clomipramine and yohimbine indicated a clinically significant drug-drug interaction for MD YOH in combination with CLOMI. This might be explained by competitive, CLOMI-related inhibition of YOH metabolism, probably mediated by cytochrome P450 2D6. However, according to European Medicines Agency guidelines, the effect can be classified as interaction absent (<1,25 fold) or minor (>1.25-<2-fold). Given the complimentary mechanisms of action and the favourable safety profiles, the findings pave the way for future efficacy studies.

Implementation of a community-based LC-UV drug checking service: promising preliminary findings on feasibility and validity

BackgroundThe increasing diversity of psychoactive substances on the unregulated drug market poses significant health, psychological, and social risks to people who use drugs (PWUD). To address these risks, various harm reduction (HR) policies have been implemented, including drug checking services (DCS). Many analytical methods are used for DCS. While qualitative methods (e.g., thin layer chromatography, spectroscopy) are easier to implement, they are not as accurate as quantitative methods (e.g., LC-UV, LC-MS). Some HR programmes have implemented high-performance liquid chromatography coupled with UV detection (LC-UV). This article presents the cross-validation of this quantitative method with a reference liquid chromatography coupled with high resolution mass spectrometry (LC-HRMS) method.MethodsDrug samples were provided by PWUD to a DCS called DrugLab in Marseille, France. The samples were weighed and prepared through dissolution in methanol, followed by ultrasonic bathing. Samples were analysed onsite using LC-UV analysis. They were then subsequently analysed with the reference LC-HRMS method. The LC-UV instrument in DrugLab was calibrated after being purchased; analysis of standard solutions was routinely performed once a month and after maintenance operations. For the LC-HRMS instrument, calibration and quality control procedures followed European Medicines Agency (EMA) guidelines. Statistical analyses were conducted including Spearman correlation tests using IBM® SPSS® Statistics version 20.ResultsA total of 102 samples representing different product classes and cutting agents were cross-validated. Differences between both analyses methods for each molecule analysed were ≤ 20%, with significant correlations between both methods’ results for most substances. Notably, LC-HRMS provided lower concentration values for cocaine and acetaminophen, whereas it provided higher values for other substances. Correlations were significant for cocaine, ketamine, MDMA, heroin, amphetamine, caffeine, acetaminophen, and levamisole.ConclusionsThis study demonstrates that the results provided by DrugLab were accurate and reliable, making LC-UV an adaptable, stable, and suitable analytical method for simple matrices like drugs in a DCS context. However, this cross validation does not guarantee accuracy over time. A proficiency test project in HR laboratories across France is currently under development in order to address potential drifts in LC-UV accuracy.

A liquid chromatography - Tandem mass spectrometry method for determination of ocrelizumab in serum of patients with multiple sclerosis

Ocrelizumab is a second generation recombinant humanized IgG1 monoclonal antibody used for the treatment of multiple sclerosis that selectively target B cells expressing the CD20 antigen. This study aimed to develop and validate a UPLC-MS/MS method for quantification of ocrelizumab in human serum, which can be used in clinical applications for therapeutic drug monitoring.The analysis of ocrelizumab was performed using a bottom-up approach on a liquid chromatography coupled to tandem mass spectrometry detection. The method involved immunoglobulin precipitation with cold methanol followed by peptide digestion with trypsin. The resulting specific peptides were separated on an Acquity UPLC BEH C18 column at 55 °C using gradient elution. The method was validated according to European Medicines Agency (EMEA) guidelines and demonstrated intra- and inter-assay precision with coefficients of variation ranging from 1.6 % to 6.1 % and accuracies between 90.2 % and 107.2 %. Stability testing, including autosampler, long-term and freeze-thaw stability, showed no more than 15 % variation. The method was successfully applied to 169 patient samples, revealing ocrelizumab concentrations ranging from 0.5 to 21.8 mg/L in patients on 6-month dosing regimen and 20.5–65.0 mg/L in 16 patients receiving an initial two-week dose of 300 mg. The newly developed UPLC-MS/MS method met all criteria for accuracy, precision and stability, confirming its suitability for clinical use in monitoring ocrelizumab levels in multiple sclerosis patients.

Assessment of changes in antibiotic use in grow-finish pigs after the introduction of PRRSV in a naïve farrow-to-finish system

Responsible antibiotic usage (ABU) is crucial for both animal and human health and requires constant improvement of antimicrobial stewardship (AMS). The presence of porcine reproductive and respiratory syndrome virus (PRRSV), a viral pathogen with immunosuppressive effects on swine, can intensify bacterial co-infections, alter antibiotic pharmacokinetics, and potentially lead to increased ABU. This study aimed to measure ABU changes in the grow-finish population associated with PRRSV infection and describe the antibiotic classes employed to manage clinical signs from a farrow-to-finish genetic multiplier system. Three PRRSV statuses (naïve, positive epidemic, and positive endemic) were established to classify the lots based on PRRSV circulation, with a total of 135,063 animals evaluated. The number of pig treatments per animal days at risk (PTDR) was calculated by administration route to quantify ABU across PRRSV status using negative binomial regression and non-parametric tests (P-value < 0.05). Moreover, to improve ABU comparability in the international scenario, the milligrams per population correction unit (mg/PCU) was calculated according to the European Medicines Agency guidelines. In the nursery phase, there was a statistically significant difference between PRRSV statuses for the overall PTDR (injectable and water routes of administration), with an ABU increase of 3.79 and 2.51 times the naïve PTDR for positive epidemic and endemic status, respectively. For the finishing phase, there was a statistically significant difference between PRRSV statuses in the injectable PTDR, with an ABU increase of 2.74 and 2.28 times the naïve PTDR level for positive epidemic and endemic statuses, respectively. In the nursery phase, the mean mg/PCU was 22.27 mg/PCU for naïve, 86.71 for positive epidemic, and 33.37 for positive endemic statuses; in the finishing phase, 81.31, 76.55, and 67.09 mg/PCU, respectively. The most frequently injected antibiotic in the nursery phase was ampicillin, with 49 % of total injections, followed by lincomycin (31 %) and enrofloxacin (20 %), and in the finishing phase, 72 % of injections were lincomycin, followed by enrofloxacin (28 %). The results highlight that the PRRSV outbreak in the source was associated with a grow-finish ABU increase, revealing the importance of preventing PRRSV infection to potentially decrease ABU and improve AMS within swine production systems.

Pharmacokinetic Pattern of Menbutone in Calves after Single Intravenous and Intramuscular Administration.

Menbutone is a choleretic agent currently used in Europe to treat digestive disorders in livestock and dogs. Pharmacokinetic parameters were established in 4-month Holstein calves after intravenous (IV) and intramuscular (IM) administration. The drug was administered to 12 animals (10 mg/kg) for both IV and IM routes following a crossover design. Plasma samples were collected at various time points over 24 h and analyzed by reverse-phase high-performance liquid chromatography with a photodiode-array detector, following a method validated according to European Medicines Agency guidelines. Pharmacokinetic parameters were calculated using compartmental and non-compartmental methods. Menbutone followed a two-compartment open model after IV injection, with a total clearance (Cl) of 71.9 ± 13.5 mL/h/kg, an elimination half-life (t½β) of 4.53 ± 2.45 h, and a volume of distribution at steady-state (Vss) of 310.4 ± 106.4 mL/kg. Non-compartmental elimination half-life (t½λ) was 4.2 ± 1.1 h. After IM administration, drug pharmacokinetics was best described by a one-compartment open model. The peak plasma concentration (Cmax) was 15.1 ± 4.3 µg/mL; the time to reach Cmax (tmax), 1.66 ± 0.55 h; and the mean absorption time (MAT), 2.50 ± 1.42 h. Absorption was high, with a fraction of the dose absorbed (F) of 83.5 ± 22.4%. Menbutone was rapidly eliminated from plasma for both routes of administration, with a fast and high IM bioavailability.

A quantitative LC-MS/MS method for investigation of polysubstance use involving heroin and cocaine

Concurrent use of heroin and cocaine (known as the “speedball”) prevails among substance use disorder populations, especially in opioid-dependent individuals, with severe consequences and a high fatality rate. Little is known about the patterns and correlations of the concurrent use of heroin and cocaine. It is vital to investigate such a polydrug use in both humans and animals to uncover concomitant toxicity and the cause of fatal overdose (death). In this study, we aimed to shed some light on the role of cocaine in the etiology of heroin-related deaths in the context of molecular pharmacokinetics (PK). For the purpose, a high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of heroin, cocaine, and their metabolites in whole blood was developed and fully validated in accordance with the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines. Then, this method was used to analyze heroin, cocaine, and their metabolites in blood from the rats intraperitoneally administered non-lethal 10 mg/kg heroin or 20 mg/kg cocaine alone, or their combination that is lethal with a proximal mortality of 33 %. The obtained results from the rats that experienced the lethal toxicity revealed that the concurrent use of heroin and cocaine significantly increased the risk of fatality from overdose. Heroin significantly slowed down the elimination of cocaine and its main metabolites in blood, while cocaine significantly enhanced heroin metabolism from 6-monoacetylmorphine (6-MAM) to morphine. Similar elimination half-lives for other heroin metabolites were observed. These findings are reported for the first time in this study, facilitating our understanding of the polysubstance metabolism and severe consequences produced by the polydrug use.

Development and Validation of a Sensitive Liquid Chromatography-Tandem Mass Spectrometry Method for Therapeutic Drug Monitoring of Ceftolozane and Tazobactam in Human Plasma Microsamples.

Ceftolozane/tazobactam (C-T) is a novel beta-lactam/beta-lactamase inhibitor combination approved for the treatment of various infections caused by difficult-to-treat Pseudomonas aeruginosa. In critically ill patients, C-T may exhibit significant pharmacokinetic variability, both between individuals and within individuals, warranting therapeutic drug monitoring for clinical purposes. We aim to develop and validate a novel and sensitive analytical method for concurrently determining C and T in human plasma microsamples (3μL). The method was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with positive electrospray ionization and multiple reaction monitoring (MRM) detection modes, employing specific mass transitions for both drugs. Sample preparation was simple, and the chromatographic run lasted only 4 minutes. Validation was conducted according to European Medicines Agency (EMA) guidelines, encompassing specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, and drug stability. The validated method was applied to measure C and T in 32 plasma samples collected from critically ill patients with multidrug-resistant, gram-negative, bacterial infections. The method ensured accurate (BIAS% 2.1-9.6 for C and -2.2 to 15.2 for T) and precise intraday CV% for C: 6.7-5.5; for T: 1.3-8.9; interday CV% for C 6.0-10.8; for T 4.1-10.2) measurements of C-T over a wide concentration range (0.2-200.0 mg/L for C and 0.1-100.0 mg/L for T). Overall, the recovery at quality control concentration levels was high for both C and T (mean values: 90-91 for C and 89-92 for T). Analyte stability was satisfactory in both human plasma and extracts under various storage conditions. The clinical applicability of the assay was confirmed by the reliably quantifying C and T in clinical plasma samples. The developed and validated LC-MS/MS method is sensitive and suitable for monitoring C and T in human plasma microsamples.

Brief Report: Can a Fraction of the Dolutegravir Dispersible Tablet Solution be Used to Dose Neonates?

Background: The smallest dolutegravir (DTG) dose approved is 5 mg once-daily in infants ≥4 weeks and weighing ≥3 to &lt;6 kg using a dispersible tablet (DT). Neonates (&lt;28 days of life) may require a lower dose due to immature organ development. We evaluated the aqueous dispersibility of the generic DTG-DT 10-mg scored tablets (Viatris Inc.) to determine the possibility of uniform concentrations that could allow for lower daily doses in neonates. Methods: Each 5-mL polypropylene tube had DTG-DT 5 mg dissolved in 5-mL ultrapure water. Tubes were labeled with 3 “zones” (bottom: 0–1 mL; middle: 1–3 mL; top: 3–5 mL). Suspensions were mixed by swirling or swirling with a syringe pump, vortexing, or sonication. DTG concentration in each zone was determined using high-performance liquid chromatography. Tubes were rinsed with 1-mL acetonitrile to determine the residual drug. Acceptable criterion for percentage difference was set at ≤20% according to the European Medicines Agency guidelines. Results: Dispersion of DTG-DT in water did not remain homogeneous, resulting in DTG concentrations that varied by over 50% across the 3 zones within the tubes. Rapid sedimentation was observed shortly after mixing. Furthermore, it was found that 24%–35% of the DTG residue remained adhered to the tube after the aqueous dispersion had been eluted, highlighting the importance of the rinse step. Conclusions: Aqueous dispersion of the DTG-DT is not uniform and displays a high degree of sedimentation. It is therefore not possible to administer a fraction of the dispersion (lower DTG dose) to neonates by using this formulation.

Evaluation of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Analysis of Glucosylceramide and Galactosylceramide Isoforms in Cerebrospinal Fluid of Parkinson's Disease Patients.

Mutations in GBA1, encoding glucocerebrosidase beta 1 (GCase), are the most common genetic risk factor for Parkinson's disease (PD). GCase dysfunction leads to an accumulation of glucosylceramide (GluCer) substrates in different organs and fluids. Despite the challenges in quantifying GluCer isoforms in biological samples, their potential clinical interest as PD biomarkers justifies the development of robust assays. An extensively evaluated high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for quantifying 14 GluCer and galactosylceramide (GalCer) isoforms in human cerebrospinal fluid (CSF) samples is presented. Sample pretreatment, HPLC, and MS/MS parameters were optimized. Evaluation was performed according to the recommendations of the Clinical and Laboratory Standards Institute and European Medicines Agency guidelines. Four 7-point calibration curves were generated, with a linearity interval from 2.5 to 200 nM (R2 ≥ 0.995). The limit of quantification was set at 5 nM. Between-run precision and accuracy were up to 12.5 and 9%, respectively. After method validation, we measured the levels of GluCer and GalCer isoforms in CSF human samples, including 6 healthy controls (HC), 22 idiopathic GBA1 wild-type PD (iPD) patients, and 5 GBA1-associated PD (PD-GBA) patients. GluCer/GalCer median ratios were found to be higher in the CSF of PD-GBA patients, particularly in severe GBA1 mutations, than those in iPD and HC. The observed trends in GluCer/GalCer ratios among groups provide novel information for the comprehensive analysis of sphingolipids as potential biomarkers of PD.

Programme for Studying Medicinal Products for Generalised Anxiety Disorder: Analysis of the European Medicines Agency Guideline

INTRODUCTION. Generalised anxiety disorder (GAD) is the least studied anxiety disorder, as patients present with comorbid mood disorders. Finding effective treatment methods for GAD is of the utmost importance; therefore, it is essential to develop novel medicinal products for GAD. Proper clinical programme design is key to obtaining reliable data on the effectiveness and safety of a medicinal product. Currently, the Russian Federation lacks methodological guidelines for clinical studies of these medcinal products, and there is a need for developing such guidelines.AIM. This review aimed to assess the possibility of applying the methodological approaches described in international guidelines to Russian clinical trials to develop medicinal products for GAD.DISCUSSION. Having analysed the main provisions of the Guideline on the clinical investigation of medicinal products indicated for generalised anxiety disorder by the European Medicines Agency (EMA), the authors of this review outlined the main stages of clinical development and the methodology for using clinical data to evaluate the safety and efficacy of medicinal products for GAD. Clinical development programmes for these medicinal products should take into account research staging and mandatory long-term safety and additive effect assessments. This review highlights aspects of selecting the design, population, and primary and secondary endpoints for a clinical trial. Particular attention is paid to the consideration of comorbidities in patients.CONCLUSION. The provisions set forth in the EMA guideline can inform the development of national guidelines for studying medicinal products for GAD.

Comparative Study of Analytical Method Validation and Process Validation parameters as per ICH, EMA, WHO and ASEAN guidelines

Objective: Compare and analyse analytical method validation and process validation requirements across ICH, EMA, WHO, and ASEAN guidelines, alongside relevant literature. Summary: In the pharmaceutical industry, ensuring the quality, safety, and effectiveness of medicinal products is of utmost importance. Analytical Method Validation (AMV) and Process Validation (PV) are critical procedures in pharmaceutical manufacturing, vital for upholding product quality and adhering to regulatory standards. This thesis undertakes a comparative examination of AMV and PV guidelines from prominent regulatory authorities, including the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), the European Medicines Agency (EMA), the World Health Organization (WHO), and the Association of Southeast Asian Nations (ASEAN). The study delves into the foundational principles, methodologies, and regulatory requirements outlined by each guideline to assess their alignment and differences. It scrutinizes key aspects such as validation parameters, acceptance criteria, documentation requirements, and statistical approaches to identify commonalities and disparities among the guidelines. Furthermore, this research aims to offer insights into the practical implications of adhering to multiple regulatory frameworks concurrently. It examines the challenges pharmaceutical companies encounter in navigating divergent requirements and harmonizing validation processes across various regions. Additionally, potential strategies to streamline compliance efforts and optimize resource allocation are explored. By synthesizing the findings of this comparative analysis, stakeholders in the pharmaceutical industry can gain a comprehensive understanding of the regulatory landscape governing AMV and PV practices. Moreover, the insights derived from this study can inform the development of harmonized validation protocols that facilitate global market access while maintaining the highest standards of product quality and patient safety. Conclusion: Notable variations exist in validation approaches, but all emphasize product quality, safety, and efficacy. Pharmaceutical companies must navigate diverse regulatory landscapes for compliance.

Quantification of Efavirenz Hydroxymetabolites in Human Plasma Using LC-HRMS/MS.

Efavirenz (EFV) is a drug used to treat HIV. Low plasma concentrations of EFV result in suboptimal viral suppression, whereas high concentrations can cause adverse neuropsychiatric side reactions. Some studies have identified a correlation between the plasma concentrations of EFV metabolites and neurotoxicity. To our knowledge, no studies have investigated the metabolism of EFV in young children and its effect on treatment outcomes. Therefore, the aim of this study was to develop and validate a method for quantifying EFV and its metabolites in human plasma derived from children. Sample preparation was performed using protein precipitation of 100 µL plasma. Thereafter, an aliquot of the supernatant was used to quantify EFV, 7-hydroxyefavirenz (7-OH-EFV), 8-hydroxyefavirenz (8-OH-EFV), and a newly discovered metabolite ("EFAdeg") associated with 8-OH-EFV. A second aliquot of the supernatant was hydrolyzed using β-glucuronidase/arylsulfatase and used with the first aliquot to quantify phase II metabolites. The analyses were performed using a Dionex Ultimate 3000RS LC-system coupled with a Q Exactive Orbitrap mass spectrometer. The method has a measuring range of 100-50,000 ng/mL (EFV, 8-OH-EFV), 125-25,000 ng/mL (7-OH-EFV), and 200-10,000 ng/mL ("EFAdeg"). All criteria of the European Medicines Agency guidelines regarding precision, accuracy, and selectivity were met. Of note, carryover must be considered for 8-OH-EFV. Overall, the validated method was successfully applied to plasma samples obtained from children and confirmed the presence of the newly discovered metabolite, "EFAdeg." An LC-HRMS/MS method for the quantification of EFV and its phase I and II metabolites was developed and validated. This method is suitable for analyzing plasma samples from children. Furthermore, studies using this method identified an additional metabolite that may influence the concentration of 8-OH-EFV in patient samples.

Effects of two commonly used antidepressants amitriptyline and fluoxetine on the pharmacokinetics of abrocitinib in rats

Abrocitinib is approved to treat moderate-to-severe atopic dermatitis and eliminated mainly through cytochrome P450 (CYP450) enzyme. Two commonly used antidepressants, amitriptyline and fluoxetine, could inhibit the activities of CYP2C19 and CYP3A4. In this study, we developed a new and quick ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for quantitatively analyzing the plasma concentration of abrocitinib, and further investigated the effects of amitriptyline or fluoxetine on the pharmacokinetics of abrocitinib in rats. The selectivity, linearity, recovery, accuracy, precision, matrix effect and stability of UPLC-MS/MS assay were satisfied according to the United States Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines. Our result showed that when co-administered with amitriptyline and fluoxetine, the CLz/F of abrocitinib was reduced by 44.4 % and 33.3 %, respectively, while the AUC(0–t) of abrocitinib was increased by 77.7 % and 49.4 %, respectively. It indicated that amitriptyline and fluoxetine could significantly increase the plasma concentration of abrocitinib in rats. Thus, dose adjustment of abrocitinib may be required when it is combined with amitriptyline or fluoxetine in ongoing clinical practice.

Validation of Novel High-Performance Liquid Chromatography Method for Meropenem Quantification in Plasma

Eminent societies of clinicians worldwide advise the implementation of therapeutic monitoring of meropenem. Our aim was to validate the new high-performance liquid chromatography (HPLC) technique for the measurement of meropenem in plasma that we developed. The validation of the method was performed in accordance with the official European Medicines Agency (EMA) guideline for bioanalytical method validation through the assessment of the following validation parameters: linearity and limit of detection/quantification, trueness and precision, recovery, selectivity, matrix-effect assessment, dilution integrity, carry-over assessment, and stability. Our calibration curve was found to be linear over the concentration ranges of 1.25–100 μg/mL, which covers the therapeutic range of meropenem in patients. From the calibration curve, the limits of detection and quantification were calculated to be 0.4 μg/mL and 1.2 μg/mL, respectively. Recovery ranged from 81.7 to 95.9 percent. Intra-day truennes ranged from −1.9 to 2.6% and inter-day trueness ranged from −4.7 to 3.8%. Intra-day precision was less than 4 percent, while inter-day precision was less than 7 percent. Meropenem remained stable in the patient plasma sample for one week at −20°C. Our HPLC technique can be applied in clinical practice for the therapeutic monitoring of meropenem in critically ill and other vulnerable patients since it is simple, rapid, and reliable.

Antidiabetic action of the Chinese formula Shouhuitongbian and the underlying mechanism associated with alteration of gut microbiota

BackgroundThe prevalence and incidence of type 2 diabetes mellitus (T2DM) have dramatically increased. The intestinal flora and its derived metabolites are demonstrated to play vital roles in the etiology and onset of T2DM. Shouhuitongbian (SHTB) is a traditional Chinese formula to treat constipation. SHTB is composed of seven herbs and components of Colla corii asini (CCA) that are obtained from the hide of Equus asinus L.. Some of herbs in SHTB such as Aloe vera (L.) Burm.f., Cassia obtusifolia L., fruits of Lycium barbarum L., and Citrus aurantium L. have shown to improve insulin resistance (IR) and T2DM in early reports. We hypothesized that SHTB composed of these herbs has antidiabetic effects. The antidiabetic efficacy and mechanism of action of SHTB have not been previously reported. Hypothesis/PurposeTo demonstrate the antidiabetic effect and elucidate the underlying mechanisms of SHTB from the perspective of gut microbiota. Study designThe main compounds were identified and quantified by high-performance liquid chromatography (HPLC)-mass spectrometry analysis. High fat diet (HFD)-fed mice and db/db mice were used to assess the antidiabetic effects and the mechanism of SHTB. The underlying mechanisms were evaluated by enzyme-linked immunosorbent assay (ELISA), western blot analysis, quantitative real time polymerase chain reaction (qPCR) analysis, 16S rRNA high-throughput sequencing, and targeted metabolome analysis. MethodsHFD-fed mice and db/db mice were orally treated with the standard positive drug metformin (100 mg/kg/d) and with SHTB (200 and 100 mg/kg/d), which was chemically characterized according to the European Medicine Agency (EMA) guidelines. The beneficial effects of SHTB were studied by homeostasis model assessment of insulin resistance (HOMA-IR) index, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), total cholesterol (T-CHO), triglyceride (TG), and inflammation. Subsequently, 16S rDNA-based high-throughput pyrosequencing and GC-MS-based targeted metabolomics profiling were performed to analyze the gut microbiota composition and metabolites profile in the gut, respectively. Moreover, the mammalian target of rapamycin complex 1 (mTORC1) / insulin receptor substrate 1 (IRS-1) / phosphoinositide 3-kinase (PI3K) / protein kinase B (AKT) pathway was evaluated via qPCR and western blot. ResultsChemically characterized SHTB, in which six markers were quantified, effectively alleviated glucose intolerance and IR, ameliorated lipid metabolism dysfunction, and reduced inflammation. In addition, 16S rDNA sequencing found that SHTB reshaped the composition of intestinal flora, as indicated by the enrichment of Akkermansia and Parabacteroides in both HFD-fed and db/db mice. Moreover, SHTB enhanced the intestinal production of short-chain fatty acids (SCFAs) and branched short-chain fatty acids (BSCFAs), and reduced the levels of the fecal and circulating branched-chain amino acids (BCAAs). The IRS-1/PI3K/AKT signaling pathway was upregulated after treatment with SHTB. ConclusionOrally administration of SHTB effectively improved IR and reduced hyperglycemia in mice. Treatment with SHTB regulated the gut BCAAs-mTORC1/IRS-1/PI3K/AKT axis by enhancing the BCAAs catabolism in the gut, which attenuated the deleterious effect of BCAAs on the IRS-1 signaling pathway.

Therapeutic drug monitoring of vancomycin in surgical patients using a validated HPLC method.

Vancomycin is being used for the treatment of a variety of infections caused by methicillin resistant Staphylococcus aureus and methicillin susceptible Staphylococcus aureus. Therapeutic drug monitoring (TDM) is highly recommended for ensuring the safe and effective therapy with vancomycin. A reliable and cost-effective bioanalytical method is required for TDM as well as pharmacokinetic studies of vancomycin. A selective, sensitive, and cost effective HPLC method was developed and validated for quantification of vancomycin concentrations in human plasma. The mobile phase was a mixture of buffer (50 mM ammonium dihydrogen phosphate, pH 2.4) and acetonitrile 88 : 12 v/v. The separation was carried on C18 column (125 × 4.6 mm, particle size 5 µm) with isocratic flow rate of 0.370 mL/min at room temperature with UV detection at 215 nm. The method was validated for sensitivity, accuracy, and precision as well as stability of vancomycin in human plasma by following European Medicine Agency (EMA) guideline. Therapeutic drug monitoring of vancomycin was performed by quantifying the trough concentrations of vancomycin in 65 human plasma samples after administration of therapeutically relevant dose. The developed method was sensitive enough to quantify vancomycin concentrations as low as 0.25 mg/L in human plasma. Moreover, the method was proved accurate and precise in terms of quantifying the unknown concentration of vancomycin. The evaluation of short-term, long-term, and freeze-thaw stability proved the stability of vancomycin in human plasma. The TDM of vancomycin by using this method showed that 39 (60%) samples were within the target trough concentration range (TTCR), i.e. 10 - 20 mg/L, while 23 samples (35.4%) were below the TTCR, and 3 samples (4.6%) were above this range. The developed method is sensitive and cost effective for quantification of vancomycin in human plasma. The results of sample analysis shows that the developed method can be used reliably for TDM of vancomycin.

Analysis of vitamin D and its metabolites in biological samples – Part II: Optimization of a sample preparation method for liver tissue

Extraction of vitamin D, including its hydroxylated and esterified metabolites, from soft tissues such as the liver is challenging due to the lipophilic character of matrix and analytes that are expected in very low concentration levels.In this study, we aimed at the optimization of two-step extraction using solid–liquid extraction as the first step, followed by solid-phase extraction. Various solvents, including ethanol, acetonitrile, methanol, acetone, heptane, and heptane with isopropanol, were investigated to isolate vitamin D compounds from liver tissue in the first step. Acetone was finally selected as the most suitable solvent for the solid–liquid extraction, with the highest recovery in the range of 67 – 98% for polar hydroxylated forms and 3 – 28% for lipophilic vitamin D and esters. Two solid phase extraction (SPE) based on the (i) “bind and elute strategy” and (ii) “removal strategy” using hydrophilic-lipophilic balanced SPE sorbent were optimized as a proceeding step for acetone extracts to increase the method selectivity. Finally, two optimized methods, combining solid–liquid extraction and individual SPE strategy, were examined in terms of sensitivity, recovery, matrix effect, accuracy, and precision.The limits of quantification were in the range of 1 – 10 ng/mL and 3 – 20 ng/mL analyzed by ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography hyphenated a with tandem mass spectrometer, respectively. The absolute recovery determined for the “bind and elute strategy” protocol was in the range of 3 – 24 %. Nevertheless, this method was free of matrix effects, which were determined to be in the 73 – 120 % range. On the contrary, the “removal strategy” approach provided higher recovery values for all compounds (47 – 123 %), but the results for nonpolar vitamin D and esters were strongly affected by signal suppression (matrix effects 3 – 51 %). Both methods fulfilled the criteria for accuracy and precision requested by the European Medicine Agency Guideline on Bioanalysis.“Removal strategy” SPE with decreased manual intervention and lower solvent consumption was finally applied to mouse liver tissue to determine vitamin D and its hydroxylated and esterified metabolites for the first time. The results, i.e., vitamin D esters detected in liver tissue, supported the notion that esters of vitamin D can be stored in lipophilic tissues to release vitamin D.

Bottom-up production of injectable itraconazole suspensions using membrane technology

Bottom-up production of active pharmaceutical ingredient (API) crystal suspensions offers advantages in surface property control and operational ease over top-down methods. However, downstream separation and concentration pose challenges. This proof-of-concept study explores membrane diafiltration as a comprehensive solution for downstream processing of API crystal suspensions produced via anti-solvent crystallization. It involves switching the residual solvent (N-methyl-2-pyrrolidone, NMP) with water, adjusting the excipient (d-α-Tocopherol polyethylene glycol 1000 succinate, TPGS) quantity, and enhancing API loading (solid concentration) in itraconazole crystal suspensions. NMP concentration was decreased from 9 wt% to below 0.05 wt% (in compliance with European Medicine Agency guidelines), while the TPGS concentration was decreased from 0.475 wt% to 0.07 wt%. This reduced the TPGS-to-itraconazole ratio from 1:2 to less than 1:50 and raised the itraconazole loading from 1 wt% to 35.6 wt%. Importantly, these changes did not adversely affect the itraconazole crystal stability in suspension. This study presents membrane diafiltration as a one-step solution to address downstream challenges in bottom-up API crystal suspension production. These findings contribute to optimizing pharmaceutical manufacturing processes and hold promise for advancing the development of long-acting API crystal suspensions via bottom-up production techniques at a commercial scale.

Comparative physicochemical and structural characterisation studies establish high biosimilarity between BGL-ASP and reference insulin aspart

Biosimilar insulin analogues are increasing market access for diabetic patients globally. Scientific establishment of biosimilarity is cornerstone of this key change in the medical landscape. BGL-ASP is a biosimilar insulin aspart developed by BioGenomics Limited, India. BioGenomics has considered a stepwise approach in generating the totality of evidence required to establish similarity with reference product. Insulin aspart is a recombinant rapid-acting human insulin analogue utilised in the treatment of type-1 and type-2 diabetes mellitus. The single amino acid substitution at position B28 where proline is replaced with aspartic acid results in a decreased propensity to form hexamers, thus increasing the absorption rate on subcutaneous administration compared to native insulin. In order to establish the safety and efficacy of BGL-ASP, the critical quality attributes (CQAs) of BGL-ASP are identified based on the impact created on biological activity, pharmacokinetic/pharmacodynamic (PK/PD), immunogenicity and safety. The CQAs of insulin aspart are related to product structure, purity and functionality and are characterised using a series of state-of-the-art orthogonal analytical tools. The primary protein sequence, the secondary, tertiary and quaternary structure are found to be highly similar for BGL-ASP and reference product. The product related impurities of insulin aspart and the assay content are determined using high performance liquid chromatography (HPLC) based analysis and is similar for BGL-ASP and reference insulin aspart sourced from United States of America (US), Europe Union (EU) and India. The safety, efficacy and immunogenicity of BGL-ASP is also found to be comparable with reference product and is confirmed through the clinical trials conducted as recommended by International Council for Harmonisation of Technical Requirements of Pharmaceuticals for Human Use (ICH) and European Medicines Agency (EMA) guidelines. The data encompassed in this study demonstrates that reference insulin aspart and BGL-ASP are highly similar in terms of structural, physicochemical, and biological properties, thus confirming its safety and efficacy for usage as potential alternative economical medicinal treatment for diabetes mellitus.