Aplicación de un modelo farmacocinético poblacional para el seguimiento de pacientes en tratamiento con dolutegravir: estudio piloto

Introducción: a pesar de los avances en tratamiento antirretroviral, existe la posibilidad de que personas que viven con el virus de la inmunodeficiencia humana (VIH) experimenten falla terapéutica vinculada a múltiples factores que impactan en la respuesta al fármaco. Objetivos: evaluar la utilidad de aplicar un modelo farmacocinético en pacientes con diagnóstico de VIH en tratamiento con dolutegravir para el análisis de las concentraciones plasmáticas experimentales. Adicionalmente, se pretende identificar potenciales interacciones farmacológicas, evaluar adherencia y fallo terapéutico. Material y método: se realizó un estudio piloto transversal y observacional en pacientes VIH tratados con dolutegravir que incluyó la dosificación de la concentración plasmática, evaluación de adherencia mediante el cuestionario simplificado de adherencia a la medicación (SMAQ) y retiro de medicación. Se utilizó un modelo poblacional referenciado en la bibliografía para la predicción de concentraciones de dolutegravir en cada paciente y se compararon con las concentraciones experimentales. Resultados: fueron incluidos en el estudio 21 pacientes. Al cotejar las concentraciones plasmáticas experimentales con la simulación farmacocinética se encontraron diferencias para 12 pacientes, las cuales se explican por posibles interacciones farmacológicas, mala adherencia u otros factores que afectan la farmacocinética. Se detectó 38% de no adherencia de acuerdo con SMAQ y 23% de acuerdo con el retiro de medicación. Conclusiones: se expone el rol potencial de los modelos farmacocinéticos para la interpretación de concentraciones plasmáticas y se genera la necesidad de avanzar en este tipo de estudios para el establecimiento de rango terapéutico y aplicabilidad clínica.

Introduction: Despite advances in antiretroviral treatment, there is a possibility that people living with HIV may experience treatment failure linked to multiple factors that impact drug response. Objective: To evaluate the usefulness of applying a pharmacokinetic model in patients diagnosed with HIV undergoing treatment with dolutegravir for the analysis of experimental plasma concentrations. Additionally, the aim is to identify potential drug interactions, assess adherence, and therapeutic failure. Method: A cross-sectional, observational pilot study was conducted in HIV patients treated with dolutegravir, which included plasma concentration dosing, assessment of adherence using the Simplified Medication Adherence Questionnaire (SMAQ), and medication withdrawal. A population-based model referenced in the literature was used to predict dolutegravir concentrations in each patient and these were compared with experimental concentrations. Results: Twenty-one patients were included in the study. When comparing experimental plasma concentrations with pharmacokinetic simulation, differences were found for 12 patients, which can be explained by possible drug interactions, poor adherence, or other factors affecting pharmacokinetics. Non-adherence was detected in 38% according to the SMAQ and 23% according to medication withdrawal. Conclusions: The potential role of pharmacokinetic models in the interpretation of plasma concentrations is highlighted, emphasizing the need to advance in this type of studies to establish therapeutic ranges and clinical applicability.

Introdução: Apesar dos avanços no tratamento antirretroviral, existe a possibilidade de que pessoas que vivem com HIV experimentem falha terapêutica ligada a múltiplos fatores que impactam na resposta ao medicamento. Objetivos: Avaliar a utilidade da aplicação de um modelo farmacocinético em pacientes com diagnóstico de HIV em tratamento com dolutegravir para análise de concentrações plasmáticas experimentais. Além disso, pretende-se identificar potenciais interações medicamentosas, avaliar a adesão e a falha terapêutica. Método: Um estudo piloto observacional transversal foi conduzido em pacientes HIV tratados com dolutegravir que incluiu dosagem de concentração plasmática, avaliação de adesão usando o questionário simplificado de adesão à medicação (SMAQ) e retirada da medicação. Um modelo populacional referenciado na literatura foi utilizado para prever as concentrações de dolutegravir em cada paciente e compará-las com as concentrações experimentais. Resultados: 21 pacientes foram incluídos no estudo. Ao comparar as concentrações plasmáticas experimentais com a simulação farmacocinética, foram encontradas diferenças em 12 pacientes, que são explicadas por possíveis interações medicamentosas, má adesão ou outros fatores que afetam a farmacocinética. Foram detectadas 38% de não adesão segundo o SMAQ e 23% segundo retirada da medicação. Conclusões: Fica exposto o papel potencial dos modelos farmacocinéticos para a interpretação das concentrações plasmáticas e gera-se a necessidade de avançar neste tipo de estudos para estabelecer a faixa terapêutica e a aplicabilidade clínica.

A rapid and sensitive High-Performance Liquid Chromatography method with fluorescence detection for quantification of melatonin in small volume rat plasma samples: application to a preclinical study to determine the oral pharmacokinetics of melatonin under gestational conditions

Abstract A novel, simple and sensitive high-performance liquid chromatography with fluorescence detection method was developed and validated for the characterization of the preclinical pharmacokinetics of melatonin under pregnant conditions. Plasma samples (25 µL) were treated with 30 µL of ethanol absolute (containing the internal standard, IS). After a centrifugation process, aliquots of supernant (5 µL) were injected into the chromatographic system. Compounds were eluted on a Xbridge C18 (150 mm x 4.6 mm i.d., 5 µm particle size) maintained at 30°C. The mobile phase consisted in a mixture of aqueous solution of 0.4% phosphoric acid and acetonitrile (70:30 v/v). The wavelengths were set at 305 nm (excitation) and 408 nm (emission) and the total analysis time was 8 min/sample. All validation tests were obtained with accuracy and precision, according to FDA guidelines, over the concentration range of 0.005-20 µg/mL. Pharmacokinetic study showed that melatonin systemic exposure increased from day 14, with a significant difference at 19 days of gestation compared to the control group. Our findings suggest a decreased metabolism of melatonin as result of temporary physiological changes that occur throughout pregnancy. However, other maternal physiological changes cannot be ruled out.

Advances in methods and techniques for the study of polysaccharide in vivo processes and immunomodulatory mechanisms / 药学学报

In recent years, polysaccharides have received much attention because of their high safety and good immunological activity. The study of polysaccharide in vivo process is a key scientific problem that needs to be solved for polysaccharide drug development. Some progress has been made in the field of polysaccharide pharmacokinetics and immunomodulation. However, due to the lack of both chromogenic and light-absorbing groups and the complex molecular structure of polysaccharides, the in vivo processes and immunomodulatory mechanisms of polysaccharides have been slow to be investigated. The effective combination of multiple techniques can break the bottleneck of difficult tracing and unknown immunomodulatory mechanism of polysaccharides in vivo, and promote the development and utilization of polysaccharides. In this paper, we systematically summarize the key techniques in the study of polysaccharide in vivo processes and immunomodulatory mechanisms in order to provide technical references and research ideas for the study of polysaccharide in vivo processes and immunomodulatory mechanisms.

Drugs that act in the lymphatic system and lymphatic drug delivery: review and perspective / 药学学报

The lymphatic system, as well as pathological changes of the lymphatic system, underlies the progress of an array of diseases and conditions, including cancer, inflammation and autoimmune disorders, infectious diseases and metabolic syndrome. A variety of biological targets in the lymphatic system can be employed to modulate these high-burden diseases, and the pharmacokinetics and drug delivery strategies in the context of lymphatics are of critical importance to optimise drug exposure to lymphatic-related targets. As such, research and drug development in this field has gained increasing attention in recent years. This article aims to provide an overview of pharmaceutical research with a focus on the lymphatic system and therapeutic targets within the lymphatics, followed by lymphatic drug delivery approaches, which may be of interest for researchers in academia, pharmaceutical industry and regulatory sciences.

The application of positron emission tomography in the research and development of central nervous system drugs / 中国临床药理学与治疗学

Positron emission tomography (PET) now plays an important role in the research and development (R&D) of central nervous system (CNS) drugs. PET could characterize the biodistribution, pharmacokinetics, and receptor binding of CNS drugs quantitatively. The present review summarized the quantitative methods of PET used in the pharmacokinetics and receptor occupancy analysis of CNS drugs. Moreover, the present review listed various applications of PET supporting R&D of CNS drugs, which could provide a new direction for the R&D of CNS drugs.

Preparation and pharmacokinetics of flumazenil sublingual tablet / 药学实践杂志

Objective To prepare flumazenil sublingual tablets and study its bioavailability. Methods Flumazenil sublingual tablets were prepared by compressing flumazenil inclusion compound with hydroxypropyl-β-cyclodextrin as the inclusion material. In a double-cycle crossover trial, twelve beagle dogs were randomly divided into two groups, one group receiving flumazenil sublingual tablets and the other receiving flumazenil injections. LC-MS method was developed and validated to determine flumazenil plasma concentration. The pharmacokinetic parameters and bioavailability were calculated using WinNonlin pharmacokinetic software. Results In the pharmacokinetic study, AUClast of flumazenil injection and sublingual tablet was （8.41±2.15） and （8.86±2.83） h·ng·ml−1, respectively; Cmax was （10.96±2.62） and （6.36±2.14） ng/ml, respectively; tmax was （0.18±0.05） and （0.58±0.24） h, respectively. The bioavailability of flumazenil sublingual tablet was 52.68%. Conclusion Clathrates were used to prepare flumazenil sublingual tablets to achieve safe and efficient delivery. LC-MS method was established for the determination of flumazenil plasma concentration, and the advantages were simple, accurate and sensitive.

Effect of Rhei Radix et Rhizoma and Eupolyphaga Steleophaga on liver protection mechanism based on pharmacokinetics and metabonomics / 中草药·英文版

OBJECTIVE@#Based on metabonomics technology of high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) and hydrogen nuclear magnetic resonance spectroscopy (1H NMR), the pharmacokinetic characteristics and therapeutic mechanism of Rhei Radix et Rhizoma (RhRR, Dahuang in Chinese), Eupolyphaga Steleophaga (EuS, Tubiechong in Chinese) combined with RhRR acting on acute liver injury were explored.@*METHODS@#Models of acute liver injury were established, and the pharmacokinetic methods of five components of RhRR-EuS in rats were found by HPLC-MS/MS. The liver tissues of different groups of mice were analyzed by 1H NMR spectroscopy combined with multivariate statistical analysis to investigate the metabolomics of RhRR-EuS and RhRR.@*RESULTS@#Pharmacokinetic results showed there were different levels of bimodal phenomenon in different groups, and the absorption of free anthraquinone in RhRR increased after compatibility with EuS. In addition, the pathological state of acute liver injury in rats can selectively promote the absorption of emodin, chrysophanol, physcion and aloe emodin. Through 15 differential metabolites in the liver tissue of acute liver injury mice, it was revealed that RhRR-EuS and RhRR could protect the liver injury by regulating the metabolism of glutamine and glutamic acid, alanine, aspartic acid and glutamic acid, and phosphoinositide. However, the regulation of RhRR was weaker than that of RhRR-EuS.@*CONCLUSION@#For the first time, we studied the pharmacokinetics and metabolomics differences of RhRR-EuS and RhRR in rats and mice with acute liver injury, in order to provide theoretical reference for clinical treatment of liver disease by DHZCP.

Effect of Compatibility of Wujiwan on Pharmacokinetics and Tissue Distribution of Representative Components / 中国实验方剂学杂志

ObjectiveTo study the plasma pharmacokinetics and tissue distribution of five representative components in Wujiwan， and to illustrate the difference of metabolism and tissue distribution before and after compatibility. MethodHealthy male SD rats were divided into four groups， including Wujiwan group（A group， 62.96 g·L-1）， Coptidis Rhizoma group（B group， 38.4 g·L-1）， processed Euodiae Fructus group（C group， 5.88 g·L-1） and fried Paeoniae Radix Alba group（D group， 18.68 g·L-1）， with 65 rats in each group， and were administered the drugs according to the clinical dose of decoction pieces converted into the dose of the extracts. Then plasma， liver， small intestine and brain were taken at pharmacokinetic set time in each group after administration. Ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry was developed for the quantitative analysis of five representative components［berberine（Ber）， palmatine（Pal）， evodiamine（Evo）， rutecarpine（Rut） and paeoniflorin（Pae）］ in Wujiwan， their concentrations in plasma， liver， small intestine and brain were detected at different time， plasma samples were processed by protein precipitation， and tissue samples were pretreated by protein precipitation plus liquid-liquid extraction. Non-atrioventricular model was used to calculate the pharmacokinetic parameters of each component， and the parameters of each group were compared. ResultPharmacokinetic results of A group showed that area under the curve（AUC0-t） of the five representative components were ranked as follows：Ber and Pal were small intestine>liver>blood， Evo and Rut were liver>small intestine>plasma， Pae was small intestine>plasma， which was not detected in the liver， no other components were detected in brain except for Ber. In comparison with plasma and other tissues， peak concentration（Cmax） of Ber， Pal， Evo， and Rut were the highest and time to peak（tmax） were the lowest in the liver of A group. In plasma， the AUC0-t and Cmax of Evo and Rut were increased in A group compared with C group， tmax of Pea was elevated and its Cmax was decreased in A group compared with D group. In the liver， compared with B-D groups， Cmax values of 5 representative components except Pae were elevated， AUC0-t of Pae was decreased and AUC0-t of Evo and Rut were increased in the A group. In the small intestine， half-life（t1/2） of each representative components in A group was elevated and tmax was decreased， and Cmax of each representative ingredient except Pal was decreased， AUC0-t values of Ber and Pal were increased， whereas the AUC0-t values of Evo and Rut were decreased. ConclusionThe small intestine， as the effector organ， is the most distributed， followed by the liver. The pharmacokinetic parameters of the representative components in Wujiwan are changed before and after compatibility， which is more favorable to the exertion of its pharmacodynamic effects.

In vivo Pharmacokinetic Analysis of Shenbai Nanosuspension in Rats Based on Overall Composition of Chinese Materia Medica / 中国实验方剂学杂志

ObjectiveTo clarify the scientific validity of in vivo pharmacokinetic determination of the whole drug composition in Shenbai nanosuspension in rats， and to provide methodological guidance and theoretical basis for the in vivo study of multi-component complex system of traditional Chinese medicine（TCM） preparations. MethodThe concentration of the overall components， mainly total saponins and total polysaccharides in Shenbai decoction and Shenbai nanosuspension， was determined in rat plasma at different times by area under the absorbance-wavelength curve method（AUAWC）， and the concentration of individual ginsenoside Rg1 was determined by high performance liquid chromatography（HPLC）， and the methodology was verified. The pharmacokinetic parameters of the whole component were compared with those of ginsenoside Rg1 to evaluate the in vivo operational characteristics of the two preparations. ResultThe methodological investigations of AUAWC and HPLC were in accordance with the requirements. AUAWC analysis showed that the overall components in both the decoction group and the nanosuspension group showed a one-compartment model， with half-life（t1/2） of 2.43 h and 2.04 h， respectively. The relative bioavailability of Shenbai nanosuspension was 138.99%. HPLC assay showed that ginsenoside Rg1 in the decoction group and the nanosuspension group showed a two-compartment model， with distribution half-life（t1/2α） of 0.13 h and 2.55 h， and elimination half-life（t1/2β） were 14.28 h and 3.85 h， respectively. The relative bioavailability of Shenbai nanosuspension was 127.49%. Compared with Shenbai decoction， the time to peak（tmax）， peak concentration（Cmax） and area under the drug-time curve（AUC） of the overall components and ginsenoside Rg1 in Shenbai nanosuspension were increased. ConclusionThe established AUAWC can be used for the pharmacokinetic study of the overall components of TCM preparations， which is complementary to the results of individual components measured by HPLC， and can provide useful reference for the in vivo study of new dosage forms of TCM.

Total Saponins in Paridis Rhizoma： A Review / 中国实验方剂学杂志

Paridis Rhizoma possesses the functions of clearing heat and detoxifying， alleviating swelling and relieving pain， cooling the liver and calming the convulsion. Saponins are the main active components of Paridis Rhizoma. Studies have shown that total saponins in Paridis Rhizoma have obvious inhibitory effect on solid tumors such as breast cancer， lung cancer， gastric cancer， and liver cancer and non-solid tumors such as leukemia. The saponins may exert the anti-tumor effects by inhibiting the proliferation， migration， and invasion of tumor cells， regulating cell cycle， inducing apoptotic and non-apoptotic death pathways， and regulating metabolism and tumor microenvironment. Furthermore， total saponins in Paridis Rhizoma showed anti-inflammatory， antioxidant， antimicrobial， hemostatic， and uterus-contracting activities. At the same time， they may induce apoptosis of normal cells， inflammation and oxidative stress， and metabolic disorders. In recent years， the reports of liver injury， reproductive injury， gastrointestinal injury， hemolysis， and other adverse reactions caused by total saponins in Paridis Rhizoma have been increasing. Pharmacokinetic studies have shown that there are significant differences in the metabolism of total saponins in Paridis Rhizoma administrated in different ways. Injection has a fast clearance rate， while oral administration may have hepatoenteric circulation. Meanwhile， due to the low solubility and activation of P-glycoprotein （P-gp） molecular pump， the prototype absorption， intestinal permeability， and recovery rate of total saponins in Paridis Rhizoma are poor， which affects the bioavailability. The bioavailability can be improved to some extent by preparing new dosage forms or new drug delivery systems with advanced technology. This paper reviews the pharmacological effect， pharmacokinetics， and adverse reactions of Rhizoma Paridis total saponins by searching the China National Knowledge Infrastructure （CNKI）， VIP， and Web of Science with ''Rhizoma Paridis total saponins'' as the keywords， hoping to provide references for the research， development， and clinical application of such components.

Cardiac output and the pharmacology of general anesthetics: a narrative review

The relationship between cardiac output and anesthetic drugs is important to anesthesiologists, since cardiac output determines the speed with which a drug infused into the bloodstream reaches its target and the intensity of the drug's effect. But rather than focus on how anesthetic drugs affect cardiac output, this narrative review focuses on how changes in cardiac output affect the pharmacokinetics and pharmacodynamics of general anesthetics during the three phases of anesthesia. At induction, an increase in cardiac output shortens both the onset time of propofol for hypnosis and the neuromuscular blocking effect of rapid-acting neuromuscular blockers, favoring the conditions for rapid sequence intubation. During maintenance, changes in cardiac output are followed by opposite changes in the drug plasma concentration of anesthetic drugs. Thus, an increase in cardiac output followed by a decrease in the plasma concentration of the anesthetic could expose the patient to a real risk of intraoperative awakening, which can be avoided by increasing the dose of hypnotic drugs. At emergence, an increase in cardiac output secondary to an increase in pC02 allows for a more rapid recovery from anesthesia. The pC02 can be increased by adding CO2 to the respiratory circuit, lowering the ventilatory rate, or placing the patient on partial rebreathing. Finally, the reversal action of sugammadex for rocuronium-induced neuromuscular block can be shortened by increasing the cardiac output.

La relación entre el gasto cardíaco y los fármacos anestésicos es importante para los anestesiólogos puesto que el gasto cardíaco determina la velocidad con la cual un medicamento que se infunde al torrente sanguíneo llega a su diana y la intensidad del efecto del agente. Pero en lugar de concentrarnos en cómo los fármacos anestésicos afectan el gasto cardíaco, esta revisión narrativa se enfoca en cómo los cambios en el gasto cardíaco afectan la farmacocinética y la farmacodinámica de los agentes anestésicos generales durante las tres fases de la anestesia. En el momento de la inducción, un incremento en el gasto cardíaco acorta tanto el tiempo de inicio del efecto del propofol para la hipnosis como el efecto del bloqueo neuromuscular causado por los bloqueadores neuromusculares de acción rápida, favoreciendo las condiciones para la intubación de secuencia rápida. Durante la fase de mantenimiento, los cambios en el gasto cardíaco vienen seguidos de cambios opuestos en la concentración plasmática del medicamento de los agentes anestésicos. Por lo tanto, un aumento del gasto cardíaco, seguido de una reducción en la concentración plasmática del anestésico, podría exponer al paciente a un riesgo real de despertar intraoperatorio, lo cual puede evitarse aumentando la dosis de los fármacos hipnóticos. En la educción, un aumento en el gasto cardíaco secundario al incremento en el pCO2 permite una recuperación más rápida de la anestesia. El pCO2 puede aumentar agregando CO2 al circuito de la respiración, reduciendo la tasa ventilatoria, o colocando al paciente en re-inhalación parcial. Finalmente, la acción de reversión de sugammadex en caso de bloqueo neuromuscular inducido por rocuronio, puede acortarse aumentando el gasto cardíaco.

Bioequivalence of 2 formulations of montelukast (5 mg chewable tablet) in the fasting state: an open-label randomized, single-dose, 2-period, crossover study / Estudo de bioequivalência entre duas formulações de comprimidos mastigáveis de Montelucaste de 5 mg em condições de jejum: um estudo randomizado, de dose única, aberto, dois períodos, cruzado

Introduction: Montelukast, a selective and active leukotriene receptor antagonist, is one of the most common agents in asthma treatment for both adults and children. Objective: To assess whether the pharmacokinetic profiles of two formulations of montelukast were similar after a single 5 mg dose (chewable tablets), administered orally under fasting conditions, sampling blood before and 36 hours after administration. Methods: This was a randomized, 2-sequence, 2-period, crossover study of 2 chewable tablet formulations of the drug: Singulair®, provided by Merck Sharp and Dohme Farmacêutica Ltda. (reference), and generic montelukast, manufactured by Eurofarma Laboratórios S.A. (test). Plasma samples obtained from 35 participants were analyzed for montelukast through high-performance liquid chromatography coupled to tandem mass spectrometry, with montelukast-d6 as the internal standard. Peak montelukast concentrations were 299.313 (SD, 11.039) ng/mL for the reference formulation and 279.803 (SD, 10.085) ng/mL for test formulation. Results: Statistical analysis showed no significant differences between AUC0-36h, AUC0-inf, or Cmax between formulations, with the following test/reference ratios: 102.458 for AUC0-36h, 102.522 for AUC0-inf, and 93.490 for Cmax. No serious adverse events were reported during the trial. Our results demonstrated the bioequivalence of Singulair® and Eurofarma's generic montelukast. Conclusions: Our results revealed that the new generic tablets are clinically safe and can be used interchangeably with the brand name product. Eurofarma's montelukast offers a safe, effective, and cheaper treatment option for people with asthma or allergic rhinitis.

Introdução: O montelucaste, um antagonista seletivo e ativo dos receptores de leucotrienos, é um dos agentes mais comumente usados na prática clínica no tratamento da asma, tanto em adultos quanto em crianças. Objetivo: Avaliar se os perfis farmacocinéticos de duas formulações de montelucaste eram semelhantes após uma dose única de comprimidos mastigáveis de 5 mg, administrados por via oral em jejum, coletando amostras de sangue desde antes da administração até 36 horas depois disso. Métodos: Estudo comparativo randomizado, 2 sequências e 2 períodos, cruzado, de dois medicamentos em comprimidos mastigáveis: Singulair®, fornecido pela Merck Sharp e Dohme Farmacêutica Ltda. (referência) e Montelucaste 5 mg, fabricado pela Eurofarma Laboratórios S.A. (teste). Amostras de plasma obtidas de 35 indivíduos elegíveis foram analisadas para montelucaste por cromatografia líquida de alta eficiência acoplada a espectrometria de massa em tandem, tendo Montelucaste-d6 como padrão interno. As concentrações máximas de montelucaste foram 299,313±11,039 ng/mL para referência e 279,803±10,085 ng/mL para formulação de teste. Resultados: A análise estatística não mostrou diferenças significativas para AUC0-36h, AUC0-inf e nem para Cmax entre as formulações, apresentando as razões Teste/Referência: 102,458 para AUC0-36h, 102,522 para AUC0-inf e 93,490 para Cmax. Nenhum evento adverso grave foi relatado durante o estudo. De acordo com a regulamentação brasileira, o atual estudo farmacocinético demonstrou bioequivalência entre os agentes individuais e forneceu evidências de bioequivalência entre Singulair® e Montelukast fabricado pela Eurofarma. Resultado: Os resultados mostraram que os novos comprimidos genéricos são clinicamente seguros e podem ser trocados pela marca original. O montelucaste da Eurofarma oferece uma opção de tratamento mais barata, segura e eficaz para indivíduos com asma ou rinite alérgica.

Pharmacokinetics of rifampicin, isoniazid & pyrazinamide during daily & intermittent dosing: A preliminary study

Background & objectives: The National Tuberculosis (TB) Control Programme has transitioned from thrice-weekly to daily drug treatment regimens in India. This preliminary study was conceived to compare the pharmacokinetics of rifampicin (RMP), isoniazid (INH) and pyrazinamide (PZA) in TB patients being treated with daily and thrice weekly anti-TB treatment (ATT). Methods: This prospective observational study was undertaken in 49 newly diagnosed adult TB patients receiving either daily ATT (n=22) or thrice-weekly ATT (n=27). Plasma RMP, INH and PZA were estimated by high-performance liquid chromatography. Results: The peak concentration (Cmax) of RMP was significantly higher (RMP: 8.5 ?g/ml vs. 5.5 ?g/ml; P=0.003) and Cmax of INH was significantly lower (INH: 4.8 ?g/ml vs. 10.9 ?g/ml; P<0.001) in case of daily dosing compared to thrice-weekly ATT. Cmax of drugs and doses was significantly correlated. A higher proportion of patients had subtherapeutic RMP Cmax (8.0 ?g/ml) during thrice-weekly compared to daily ATT (78% vs. 36%; P=0.004). Multiple linear regression analysis showed that Cmax of RMP was significantly influenced by the dosing rhythm, pulmonary TB and Cmax of INH and PZA by the mg/kg doses. Interpretation & conclusions: RMP concentrations were higher and INH concentrations were lower during daily ATT, suggesting that INH doses may need to be increased in case of a daily regimen. Larger studies are, however, required using higher INH doses when monitoring for adverse drug reactions and treatment outcomes.

El largo y sinuoso camino de la farmacia clinica en Chile / The long and winding road of the clinical pharmacy in Chile

Clinical pharmacy is a health discipline in which pharmacists provide patient care that optimizes rational medication use and promotes health, wellness and disease prevention. The beginnings of clinical pharmacy in Chile were inspired by the origin in the School of Pharmacy of the University of California, San Francisco (UCSF), in the mid-1960s. However, the historical development in our country, both in teaching and in the professional field, was accompanied by difficulties and success, which became a long and winding road. This article shares the events that gave rise to its beginnings in Chile, first through teaching, then in pharmacovigilance and clinical pharmacokinetics, to later describe its professional expansion and recognition as a specialty of pharmacy. This article briefly recounts the history of the Chilean clinical pharmacy to this day. Some names of people or institutions were not mentioned. Therefore the authors apologize in advance to pharmacists and organizations whose contribution cannot be recognized in this way. However, we know that this specialty has not been forged only by the names that appear, but by all those who love and respect the work of the clinical pharmacy.

The influence of sepsis on antimicrobials tissue penetration: The use of microdialysis technique to access free drug distribution

Abstract Sepsis is described as a life-threatening organ dysfunction caused by a host's response to infection, leading to an unbalance in body homeostasis. It is one of the leading causes of death in developed countries. Considering that in critically ill patients, such as those with sepsis, plasma concentrations do not necessarily reflect tissue concentrations, one way to assess tissue concentrations is through the microdialysis technique, which allows direct measurements of free drug at the site of action. This review was carried out after searching the Pubmed, Scielo and Web of Science databases, using the following descriptors: (microdialysis AND (sepsis OR septic shock OR severe sepsis OR septicemia)) OR (microdialysis AND (sepsis OR septic shock OR severe sepsis) OR septicemia) AND (antimicrobial OR antibiotic OR antifungal)). The physiological changes generated by sepsis may imply changes in pharmacokinetic parameters, such as in clearance, which may be reduced in these patients and in volume of distribution, which presents an expansion, mainly due to edema. Both events contribute to a high inter- individual variability in tissue penetration of antimicrobials which is generally observed in patients with sepsis.

Pharmacokinetics and therapeutic target attainment of vancomycin in pediatric post-liver transplant patients

Abstract Introduction Vancomycin is widely prescribed to treat or prevent Gram-positive infections in pediatric liver transplant recipients. The objective of this prospective cohort study is to describe vancomycin pharmacokinetics and to evaluate the therapeutic target attainment after initial dose regimen. Materials and methods Patients with previous renal injury were excluded. Vancomycin therapy started with 40‒60 mg/kg/day. The pharmacokinetic parameters were assessed using two steady-state blood samples and the first-order kinetic equations. Therapeutic target was defined as vancomycin 24-hour Area Under the Curve/Minimum Inhibitory Concentration (AUC/MIC) ≥ 400 and < 600. Results Sixteen patients were included. The found vancomycin clearance, half-life, and volume of distribution were, respectively: 2.1 (1.3‒2.8) mL/kg/min, 3.3 (2.7‒4.4) hours, and 0.7 (0.5‒0.9) L/kg. With the initial dose, only 6 (37 %) patients reached the therapeutic target against Gram-positive pathogens with MIC 1 mg/L. After individual dose adjustments, all patients reached the target. The correlation between trough levels and AUC was low (R2= 0.5). Conclusions Pediatric patients with preserved renal function after liver transplantation have an increased volume of distribution for vancomycin, and most patients present subtherapeutic levels after the standard initial dosing regimen. With the vancomycin AUC-guided monitoring and dosing, it is possible to improve therapeutic target attainment.

Prediction of the Impact of CYP2C19 Polymorphism on Drug-Drug Interaction between Voriconazole and Tacrolimus Using Physiologically-Based Pharmacokinetic Modelling

Abstract Voriconazole increases tacrolimus blood concentration significantly when coadministrated. The recommendation of reducing tacrolimus to 1/3 in voriconazole package insert seems not to be satisfactory in clinical practice. In vitro studies demonstrated that the magnitude of inhibition depends on the concentration of voriconazole, while voriconazole exposure is determined by the genotype status of CYP2C19. CYP2C19 gene polymorphism challenges the management of drug-drug interactions(DDIs) between voriconazole and tacrolimus. This work aimed to predict the impact of CYP2C19 polymorphism on the DDIs by using physiologically based pharmacokinetics (PBPK) models. The precision of the developed voriconazole and tacrolimus models was reasonable by evaluating the pharmacokinetic parameters fold error, such as AUC0-24, Cmax and tmax. Voriconazole increased tacrolimus concentration immediately in all population. The simulated duration of DDIs disappearance after voriconazole withdrawal were 146h, 90h and 66h in poor metabolizers (PMs), intermediate metabolizers (IMs) and extensive metabolizers(EMs), respectively. The developed and optimized PBPK models in this study can be applied to assit the dose adjustment for tacrolimus with and without voriconazole.

Development and validation of liquid chromatography-tandem mass spectrometry method to quantify dasatinib in plasma and its application to a pharmacokinetic study

Abstract Dasatinib, a potent oral multi-targeted kinase inhibitor against Src and Bcr-Abl, can decrease inflammatory response in sepsis. A simple and cost-effective method for determination of an effective dose dasatinib was established. This method was validated in human plasma, with the aim of reducing the number of animals used, thus, avoiding ethical problems. Dasatinib and internal standard lopinavir were extracted from 180 uL of plasma using liquid-liquid extraction with methyl tert-butil ether, followed by liquid chromatography coupled to triple quadrupole mass spectrometry in multiple reaction monitoring mode. For the pharmacokinetic study, 1 mg/kg of dasatinib was administered to mice with and without sepsis. The method was linear over the concentration range of 1-98 ng/mL for DAS in mice and human plasma, with r2>0.99 and presented intra- and interday precision within the range of 2.3 - 6.2 and 4.3 - 7.0%, respectively. Further intra- and interday accuracy was within the range of 88.2 - 105.8 and 90.6 - 101.7%, respectively. The mice with sepsis showed AUC0-t = 2076.06 h*ng/mL and Cmax =102.73 ng/mL and mice without sepsis presented AUC0-t = 2128.46 h*ng/mL. Cmax = 164.5 ng/mL. The described analytical method was successfully employed in pharmacokinetic study of DAS in mice.

Liquid chromatography-mass spectrometry for simultaneous determination of spironolactone and canrenone in plasma samples

Abstract n our study, we aimed to validate a method based on liquid chromatography-mass spectrometry (LC-MS) to quantify spironolactone (SPI) and its active metabolite canrenone (CAN) simultaneously in plasma samples to support in vivo experiments. Compounds were separated by using a C18 column with the isocratic elution of a mobile phase composed of 0.1% (v/v) formic acid in methanol-water (60:40 v/v) at a flow rate of 0.4 mL min−1. SPI and CAN were detected in na electrospray interface operating in a positive ionization mode and quantified using the selective ion mode monitoring of mass-charge ratios (m/z) of 439.0 for SPI and 363.1 for CAN. After calculating the matrix effect using theoretical equations, we observed the strong interference of plasma in the equipment-generated signal, which required creating analytical curves using the matrix as a solvent. The method was nevertheless linear (r 2 > 0.999) in a concentration range of 0.4-5.0 µg mL−1, as well as precise, with a coefficient of variation less than 5%. SPI's and CAN's recovery rates from the plasma ranged from 87.4% to 112.1%, while their limits of detection (i.e., 0.07 µg mL−1 and 0.03 µg mL−1, respectively) and quantification (i.e., 0.20 µg mL−1 and 0.08 µg mL−1, respectively) in the presence of plasma contaminants were low. Therefore, the bioanalytical method seems to be feasible for quantifying SPI and CAN in plasma

Content determination of seven active components of Eucommiae Cortex in aortic vascular endothelial cells of spontaneously hypertensive rats by UPLC-MS/MS / 中国中药杂志

In the present study, the contents of seven active components [genipinic acid(GA), protocatechuic acid(PCA), neochlorogenic acid(NCA), chlorogenic acid(CA), cryptochlorogenic acid(CCA),(+)-pinoresinol di-O-β-D-glucopyranosid(PDG), and(+)-pinoresinol 4'-O-β-D-glucopyranoside(PG)] of Eucommiae Cortex in aortic vascular endothelial cells of spontaneously hypertensive rats(SHR) were simultaneously determined by ultra-high liquid chromatography-triple quadrupole mass spectrometry(UPLC-MS/MS). The qualified SHR models were selected. The primary aortic endothelial cells(VECs) of rats were separated and cultured by ligation and adherence, followed by subculture. After successful identification, an UPLC-MS/MS method for simultaneously determining the contents of GA, PCA, NCA, CA, CCA, PDG, PG in seven components of Eucommiae Cortex in VECs was established, including specificity, linearity, matrix effect, recovery, accuracy, precision and stability. The established method had the lo-west limit of quantification of 0.97-4.95 μg·L~(-1), accuracy of 87.26%-109.6%, extraction recovery of 89.23%-105.3%, matrix effect of 85.86%-106.2%, and stability of 86.00%-112.5%. Therefore, the established accurate UPLC-MS/MS method could rapidly and simultaneously determine the contents of the seven active components of Eucommiae Cortex in VECs of SHRs, which provided a refe-rence for the study of cellular pharmacokinetics of active components of Eucommiae Cortex extract.