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1.
Biopharm Drug Dispos ; 44(2): 147-156, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36951570

RESUMO

Pediatric drugs knowledge still leaves several gaps to be filled, all the while many biopharmaceutic properties applied to adults do not work in pediatrics. The solubility in many cases is extrapolated to pediatrics; however, sometimes it may not represent the real scenario. In this context, the aim of this study was to assess the possibility of the extrapolation of the solubility data assumed for adults to children aged 2-12 years using lamotrigine (LTG) as a model. LTG showed that its solubility is dependent on the pH of the medium, no precipitate formation was seen, and biomimetic media showed a greater capacity to solubilize it. Based on the dose number (D0 ) in adults, the LTG was soluble in acidic pH media and poorly soluble in neutral to basic. Similar behavior was found in conditions which mimic children aged 10-12 years at a dose of 5 and 15 mg/kg. The D0 for 5-year-old children at a dose of 15 mg/kg showed different behaviors between biorelevant and pharmacopeial buffers media. For children aged 2-3 years, LTG appeared to be poorly soluble under both gastric and intestinal conditions. Solubility was dependent on the volume of fluid calculated for each age group, and this may impact the development of better pharmaceutical formulations for this population, better pharmacokinetic predictions in tools as PBPK, and physiologically-based biopharmaceutics modeling, greater accuracy in the justifications for biowaiver, and many other possibilities.


Assuntos
Biomimética , Absorção Intestinal , Adulto , Humanos , Criança , Pré-Escolar , Solubilidade , Lamotrigina , Absorção Intestinal/fisiologia , Administração Oral , Modelos Biológicos , Simulação por Computador , Concentração de Íons de Hidrogênio
2.
Br J Clin Pharmacol ; 87(8): 3227-3233, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33474776

RESUMO

AIMS: To compare the pharmacokinetics of amoxicillin (AMX) in obese and nonobese subjects, given as single dose 875-mg tablets. METHODS: A prospective, single-centre, open-label, clinical study was carried out involving 10 nonobese and 20 obese subjects given a dose of an AMX 875-mg tablet. Serial blood samples were collected between 0 and 8 hours after administration of AMX and plasma levels were quantified by liquid chromatography-tandem mass spectrometry. The pharmacokinetic parameters (PK) were calculated by noncompartmental analysis and means of the 2 groups were compared using Student t-test. Analysis of correlation between covariates and PK was performed using Pearson's correlation coefficient. RESULTS: Ten nonobese subjects (mean age 30.6 ± 7.12 y; body mass index 21.56 ± 1.95 kg/m2 ) and 20 obese subjects (mean age 34.47 ± 7.03 y; body mass index 33.17 ± 2.38 kg/m2 ) participated in the study. Both maximum concentration (Cmax ; 12.12 ± 4.06 vs. 9.66 ± 2.93 mg/L) and area under the curve (AUC)0-inf (34.18 ± 12.94 mg.h/L vs. 26.88 ± 9.24 mg.h/L) were slightly higher in nonobese than in obese subjects, respectively, but differences were not significant. The volume of distribution (V/F) parameter was statistically significantly higher in obese compared to nonobese patients (44.20 ± 17.85 L vs. 27.57 ± 12.96 L). Statistically significant correlations were observed for several weight metrics vs. AUC, Cmax , V/F and clearance, and for creatinine clearance vs. AUC, Cmax and clearance. CONCLUSION: In obese subjects, the main altered PK was V/F as a consequence of greater body weight. This may result in antibiotic treatment failure if standard therapeutic regimens are administered.


Assuntos
Amoxicilina , Obesidade , Administração Oral , Adulto , Área Sob a Curva , Cromatografia Líquida , Humanos , Estudos Prospectivos , Adulto Jovem
3.
Mol Pharm ; 16(12): 5025-5034, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31721592

RESUMO

The potential of a physiologically-based pharmacokinetic (PBPK) model to predict oral amoxicillin bioavailability, by considering the physiological changes after "Roux-en-Y gastric bypass" (RYGB) surgery in bariatric patients, was evaluated. A middle-out approach for parameter estimations was undertaken using in vitro, in situ, and in vivo data. The observed versus predicted plasma concentrations and the model sensitivity of the simulated parameters of AUC0-inf and Cmax of amoxicillin (AMX) were used to confirm the reliability of the estimation. The model considers that a drug-transporter (Transp) in the initial segments of the normal intestine plays a significant role in the AMX absorption. A lower fraction absorbed (Fabs) was observed in RYGB patients (54.43% for suspension and 45.21% for tablets) compared to healthy subjects (77.48% capsule). Furthermore, the tablet formulation presented a lower dissolved fraction (Fd) and Fabs compared to the suspension formulation of AMX in RYGB patients (91.70% and 45.21% versus 99.92% and 54.43%, respectively). The AUC0-inf and Cmax were sensitive to changes in Rtintestine, PeffAMX, and Transp for both healthy and RYGB models. Additionally, AUC0-inf and Cmax were also sensitive to changes in the tlag parameter for tablet formulation in RYGB patients. The PBPK model showed a reduction in AMX bioavailability as a consequence of reduced intestinal length after RYGB surgery. Additionally, the difference in the predicted Fd and Fabs between suspension and tablet suggests that liquid formulations are preferable in postbariatric patients.


Assuntos
Amoxicilina/administração & dosagem , Amoxicilina/farmacocinética , Derivação Gástrica , Administração Oral , Humanos , Cinética , Solubilidade , Suspensões/química
4.
Br J Clin Pharmacol ; 85(5): 914-923, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30669177

RESUMO

AIMS: Pregnancy is associated with physiological changes that alter the pharmacokinetics (PK) of drugs. The aim of this study was to predict the PK of ziprasidone in pregnant women. METHODS: A full physiologically-based pharmacokinetic (PBPK) model of ziprasidone was developed and validated for the non-pregnant population (healthy adults, paediatrics, geriatrics), and this was extended to the pregnant state to assess the change in PK profile of ziprasidone throughout pregnancy. RESULTS: The PBPK model successfully predicted the ziprasidone disposition in healthy adult volunteers, wherein the predicted and observed AUC, Cmax and tmax were within the fold-difference of 0.94-1.09, 0.89-1.40 and 0.80-1.08, respectively. The paediatric and geriatric population, also showed predicted AUC, Cmax and tmax within a two-fold range of the observed values. The simulated exposure in pregnant women using a p-PBPK model showed no significant difference when compared to non-pregnant women. CONCLUSIONS: The PBPK model predicted the impact of physiological changes during pregnancy on PK and exposure of ziprasidone, suggesting that dose adjustment is not necessary in this special population.


Assuntos
Antipsicóticos/farmacocinética , Simulação por Computador , Modelos Biológicos , Piperazinas/farmacocinética , Tiazóis/farmacocinética , Adulto , Fatores Etários , Idoso , Antipsicóticos/administração & dosagem , Área Sob a Curva , Células CACO-2 , Criança , Relação Dose-Resposta a Droga , Cálculos da Dosagem de Medicamento , Feminino , Voluntários Saudáveis , Humanos , Transtornos Mentais/tratamento farmacológico , Piperazinas/administração & dosagem , Gravidez , Complicações na Gravidez/tratamento farmacológico , Tiazóis/administração & dosagem
5.
Br J Clin Pharmacol ; 85(9): 2118-2125, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31215676

RESUMO

AIMS: To evaluate the relative bioavailability of oral amoxicillin (AMX) tablets in comparison to AMX suspension in Roux-en-Y gastric bypass bariatric subjects. METHODS: A randomized, double-blind, cross-over study was performed on the bioavailability of oral AMX tablets and suspension in Roux-en-Y gastric bypass subjects operated at least 3 months previously . Doses of 875 mg of the AMX tablet or 800 mg of the AMX suspension were given to all the subjects, allowing a washout of 7 days between the periods. Blood samples were collected at 0, 0.25, 0.5, 1, 1.5, 2, 4, 6 and 8 hours after drug administration and the AMX levels were quantified by liquid chromatography coupled with triple quadrupole tandem mass spectrometry. The pharmacokinetic parameters were calculated by noncompartmental analysis, normalized to an 875 mg dose and the bioavailability of the AMX from the tablets was compared to that from the suspension formulation. RESULTS: Twenty subjects aged 42.65 ± 7.21 years and with a body mass index of 29.88 ± 4.36 kg/m2 were enrolled in the study. The maximum AMX plasma concentration of the tablets and the suspension (normalized to 875 mg) were 7.42 ± 2.99 mg/L and 8.73 ± 3.26 mg/L (90% confidence interval of 70.71-99.11), and the total area under the curve from time zero to infinity were 23.10 ± 7.41 mg.h/L and 27.59 ± 8.32 mg.h/L (90% confidence interval of 71.25-97.32), respectively. CONCLUSION: The tablets presented a lower bioavailability than the suspension formulation and the total absorbed amount of AMX in these subjects was lower in comparison to the standard AMX absorption rates in nonbariatric subjects, regardless of the formulation.


Assuntos
Amoxicilina/farmacocinética , Antibacterianos/farmacocinética , Derivação Gástrica/efeitos adversos , Administração Oral , Adulto , Amoxicilina/administração & dosagem , Amoxicilina/sangue , Antibacterianos/administração & dosagem , Antibacterianos/sangue , Área Sob a Curva , Disponibilidade Biológica , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Suspensões , Comprimidos
6.
Pharm Res ; 33(3): 776-91, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26553353

RESUMO

PURPOSE: Photodynamic therapy (PDT) with methylene blue (MB) constitutes a potentially useful modality for colorectal cancer treatment. The limitations of the formulations containing MB are problems of administration and the inability to get the closeness contact at the site during the appropriate residence time. Present study aimed to develop and characterize mucoadhesive thermoresponsive system containing MB designed as platform for colorectal cancer therapy. METHODS: Formulations composed of different amounts of poloxamer 407 (Polox), Carbopol 934P (Carb), and MB were developed and characterized as rheological, compressional, mucoadhesive and syringeability properties, toxicity, photodynamic action, in vitro MB release profile, and ex vivo MB intestinal permeation. RESULTS: The different compositions resulted in formulations with distinctive macroscopic characteristics and wide range of gelation temperatures. The compressional flow, mucoadhesive, syringeability, and rheological properties were significantly influenced by temperature and/or composition. The MB release from formulation was governed by anomalous transport. In addition, it was observed that MB permeated the intestinal membrane; the formulation possesses photodynamic activity and low toxicity. CONCLUSIONS: The data obtained from the system composed of 20% Polox, 0.15% Carb, and 0.25% MB indicated a potentially functional role in PDT of the colorectal cancer and suggest it is worthy of clinical evaluation.


Assuntos
Adesividade/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , Azul de Metileno/administração & dosagem , Azul de Metileno/química , Acrilatos/química , Animais , Células CACO-2 , Linhagem Celular Tumoral , Química Farmacêutica/métodos , Géis/administração & dosagem , Géis/química , Humanos , Masculino , Permeabilidade , Fotoquimioterapia/métodos , Poloxâmero/química , Ratos , Ratos Wistar
7.
Biomed Chromatogr ; 30(7): 1092-1096, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26577838

RESUMO

Lychnopholide is a sesquiterpene lactone usually obtained from Lychnophora and Eremanthus species and has pharmacological activities that include anti-inflammatory and anti-tumor. Lychnopholide isolated from Eremanthus matogrossenssis was analyzed in this study. The aims of this study were to develop and validate an analytical methodology by LC-MS/MS and to quantify lychnopholide in rat plasma. Chromatographic separation was achieved on a C18 column using isocratic elution with the mobile phase consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.4 mL/min. The detection was performed in multiple-reaction monitoring mode using electrospray ionization in positive mode. The method validation was performed in accordance with regulatory guidelines and the results met the acceptance criteria. The linear range of detection was 10-200 ng/mL (r > 0.9961). The intra- and inter-day assay variability were <6.2 and <11.7%, respectively. The extraction recovery was approximately 63% using liquid-liquid extraction with chloroform. Lychnopholide was detected in plasma up to 60 min after intravenous administration in rats. This rapid and sensitive method for the analysis of the sesquiterpene lactone lychnopholide in rat plasma can be applied to pharmacokinetic studies of this compound. Copyright © 2016 John Wiley & Sons, Ltd.


Assuntos
Cromatografia Líquida/métodos , Lactonas/sangue , Sesquiterpenos/sangue , Espectrometria de Massas em Tandem/métodos , Animais , Lactonas/farmacocinética , Limite de Detecção , Ratos , Reprodutibilidade dos Testes , Sesquiterpenos/farmacocinética
8.
Pharm Biol ; 54(1): 139-45, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25857682

RESUMO

CONTEXT: Oxidative stress is an important factor modulating skin alterations. Melochia arenosa Benth. (Malvaceae) is a Brazilian plant with antimicrobial activity and antioxidant potential. OBJECTIVE: The objective of this study is to develop a topical formulation containing antioxidant phenolic-rich extract of M. arenosa and to evaluate its skin permeation profile. MATERIALS AND METHODS: Response surface methodology was used to maximize the total phenolic (TP) content of the extract and its antioxidant activity was evaluated by 2,2-diphenyl-1-picryl-hydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and respiratory burst methods. An emulsion containing 1% optimized extract (OE) was developed and employed photoacoustic spectroscopy (PAS) for the determination of its skin permeation profile. The morphology of the skin was studied in histological sections stained with hematoxylin-eosin. RESULTS AND DISCUSSION: The optimum conditions predicted for the major extractive efficiency of the phenolics with 100% ethanol led extraction time 101 h and plant:solvent proportion 1:13.5 (w/v). OE presented TP = 724.6 ± 8.2 mg GAE/g extract and scavenging capacity of DPPH (IC50 value = 11.43 ± 0.14 µg/mL) and ABTS radicals (IC50 value = 35.42 ± 0.48 µg/mL). The production of ROS by neutrophils after stimulation with phorbol miristate acetate was lower when the OE was present in the reaction medium, endorsing its high antioxidant capacity. The data obtained by PAS indicated that the OE present in the emulsion has permeated and was distributed in the whole skin. No histopathological alterations were observed in the histological analysis. CONCLUSION: The formulation developed is a promising tool for skin care and could prevent the damage caused by oxidative stress.


Assuntos
Antioxidantes/metabolismo , Malvaceae/química , Fenóis/metabolismo , Técnicas Fotoacústicas , Extratos Vegetais/metabolismo , Absorção Cutânea , Pele/metabolismo , Administração Cutânea , Animais , Antioxidantes/administração & dosagem , Antioxidantes/química , Antioxidantes/isolamento & purificação , Emulsões , Humanos , Masculino , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Permeabilidade , Fenóis/administração & dosagem , Fenóis/química , Fenóis/isolamento & purificação , Fitoterapia , Componentes Aéreos da Planta , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Plantas Medicinais , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória/efeitos dos fármacos , Análise Espectral , Fatores de Tempo
9.
Planta Med ; 81(12-13): 1121-7, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26218336

RESUMO

The pharmacokinetic properties of a new molecular entity are important aspects in evaluating the viability of the compound as a pharmacological agent. The sesquiterpene lactone lychnopholide exhibits important biological activities. The objective of this study was to characterize the pharmacokinetics of lychnopholide after intravenous administration of 1.65 mg/kg (n = 5) and oral administration of 3.3 mg/kg (n = 3) lychnopholide in rats (0.2 ± 0.02 kg in weight) through nonlinear mixed effects modeling and non-compartmental pharmacokinetic analysis. A highly sensitive analytical method was used to quantify the plasma lychnopholide concentrations in rats. Plasma protein binding of this compound was over 99 % as determined by a filtration method. A two-compartment body model plus three transit compartments to characterize the absorption process best described the disposition of lychnopholide after both routes of administration. The oral bioavailability was approximately 68 %. The clearance was 0.131 l/min and intercompartmental clearance was 0.171 l/min; steady-state volume of distribution was 4.83 l. The mean transit time for the absorption process was 9.15 minutes. No flip-flop phenomenon was observed after oral administration. The pharmacokinetic properties are favorable for further development of lychnopholide as a potential oral pharmacological agent.


Assuntos
Lactonas/farmacocinética , Modelos Biológicos , Sesquiterpenos/farmacocinética , Administração Intravenosa , Administração Oral , Animais , Disponibilidade Biológica , Lactonas/química , Masculino , Estrutura Molecular , Ligação Proteica , Ratos , Ratos Wistar , Sesquiterpenos/química
10.
Planta Med ; 81(5): 373-81, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25782034

RESUMO

The aim of this study was to use the pharmacokinetic information of avicularin in rats to project a dose for humans using allometric scaling. A highly sensitive and specific bioanalytical assay to determine avicularin concentrations in the plasma was developed and validated for UPLC-MS/MS. The plasma protein binding of avicularin in rat plasma determined by the ultrafiltration method was 64%. The pharmacokinetics of avicularin in nine rats was studied following an intravenous bolus administration of 1 mg/kg and was found to be best described by a two-compartment model using a nonlinear mixed effects modeling approach. The pharmacokinetic parameters were allometrically scaled by body weight and centered to the median rat weight of 0.23 kg, with the power coefficient fixed at 0.75 for clearance and 1 for volume parameters. Avicularin was rapidly eliminated from the systemic circulation within 1 h post-dose, and the avicularin pharmacokinetic was linear up to 5 mg/kg based on exposure comparison to literature data for a 5-mg/kg single dose in rats. Using allometric scaling and Monte Carlo simulation approaches, the rat doses of 1 and 5 mg/kg correspond to the human equivalent doses of 30 and 150 mg, respectively, to achieve comparable plasma avicularin concentrations in humans.


Assuntos
Bidens/química , Flavonoides/farmacocinética , Extratos Vegetais/farmacocinética , Animais , Relação Dose-Resposta a Droga , Flavonoides/administração & dosagem , Flavonoides/sangue , Humanos , Injeções Intravenosas , Masculino , Modelos Biológicos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/sangue , Ratos Wistar , Espectrometria de Massas em Tandem
11.
CPT Pharmacometrics Syst Pharmacol ; 13(2): 208-221, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37916262

RESUMO

Physiologically-based biopharmaceutics modeling (PBBM) has potential to accelerate the development of new drug and formulations. An important application of PBBM is for special populations such as pediatrics that have pharmacokinetics dependent on the maturation process. Lamotrigine (LTG) is a Biopharmaceutics Classification System (BCS) II drug and is widely prescribed. Therefore, the goal of this study was to assess the biopharmaceutics risk of the low-soluble drug LTG when the ontogeny on gastrointestinal tract (GIT) physiological parameters are considered. An oral physiologically-based pharmacokinetic model and a PBBM were developed and verified using GastroPlus™ software for both adults and children (2-12 years old, 12-52 kg). The biopharmaceutics properties and GIT physiological parameters were evaluated by sensitivity analysis. High doses were simulated assuming a worst case scenario, that is, the dose of 200 mg for adults and 5 mg/kg (up to the maximum of 200 mg) for 2-year-old children. Although several authors have suggested that ontogeny may have an effect on gastrointestinal fluid volume, our study found no evidence of interference between fluid and dose volumes with in vivo dissolution of LTG. The most impactful parameter was found to be the gastric transit time. Therefore, the hypothesis is developed to examine whether LTG exhibits characteristics of a BCS II classification in vitro while showing BCS I-like behavior in vivo. This hypothesis could act as a base for conducting novel studies on model-informed precision dosing, tailored to specific populations and clinical conditions. In addition, it could be instrumental in assessing the influence of various release profiles on in vivo performance for both adult and pediatric populations.


Assuntos
Biofarmácia , Absorção Intestinal , Adulto , Humanos , Criança , Pré-Escolar , Lamotrigina , Absorção Intestinal/fisiologia , Solubilidade , Composição de Medicamentos , Administração Oral , Modelos Biológicos
12.
Eur J Pharm Biopharm ; 182: 81-91, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36516889

RESUMO

Gastroretentive drug delivery systems (GRDDS) are modified-release dosage forms designed to prolong their residence time in the upper gastrointestinal tract, where some drugs are preferentially absorbed, and increase the drug bioavailability. This work aimed the development of a novel GRDDS containing 60 mg of sildenafil citrate, and the evaluation of the feasibility of the proposed formulation for use in the treatment of pulmonary arterial hypertension (PAH), for once a day administration, by using in silico pharmacokinetic (PK) modeling and simulations using GastroPlusTM. The Model-Informed Drug Development (MIDD) approach was used in formulation design and pharmacokinetic exposure prospecting. A 22 factorial design with a central point was used for optimization of the formulation, which was produced by direct compression and characterized by some tests, including buoyancy test, assay, impurities, and in vitro dissolution. A compartmental PK model was built using the GatroPlusTM software for virtual bioequivalence of the proposed formulations in comparison with the defined target release profile provided by an immediate release (IR) tablet formulation containing 20 mg of sildenafil administered three times a day (TID). The results of the factorial design showed a direct correlation between the dissolution rate and the amount of hydroxypropyl methyl cellulose (HPMC) in the formulations. By comparing the PK parameters predicted by the virtual bioequivalence, the formulations F1, F2, F3 and F5 failed on bioequivalence. The F4 showed bioequivalence to the reference and was considered the viable formulation to substitute the IR. Thus, GRDDS could be a promising alternative for controlling the release of drugs with a pH-dependent solubility and narrow absorption window, specifically in the gastric environment, and an interesting way to reduce dose frequency and increase the drug bioavailability. The MIDD approach increases the level of information about the pharmaceutical product and guide the drug development for more assertive ways.


Assuntos
Sistemas de Liberação de Medicamentos , Desenvolvimento de Medicamentos , Citrato de Sildenafila , Preparações de Ação Retardada/farmacocinética , Disponibilidade Biológica , Solubilidade , Comprimidos/farmacocinética
13.
Front Pharmacol ; 14: 1068153, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36998614

RESUMO

Sildenafil is a potent vasodilator and phosphodiesterase type five inhibitor, commercially known as Revatio® and approved for the treatment of pulmonary arterial hypertension. Maternal administration of sildenafil during pregnancy is being evaluated for antenatal treatment of several conditions, including the prevention of pulmonary hypertension in fetuses with congenital diaphragmatic hernia. However, determination of a safe and effective maternal dose to achieve adequate fetal exposure to sildenafil remains challenging, as pregnancy almost always is an exclusion criterion in clinical studies. Physiologically-based pharmacokinetic (PBPK) modelling offers an attractive approach for dose finding in this specific population. The aim of this study is to exploit physiologically-based pharmacokinetic modelling to predict the required maternal dose to achieve therapeutic fetal exposure for the treatment congenital diaphragmatic hernia. A full-PBPK model was developed for sildenafil and N-desmethyl-sildenafil using the Simcyp simulator V21 platform, and verified in adult reference individuals, as well as in pregnant women, taking into account maternal and fetal physiology, along with factors known to determine hepatic disposition of sildenafil. Clinical pharmacokinetic data in mother and fetus were previously obtained in the RIDSTRESS study and were used for model verification purposes. Subsequent simulations were performed relying either on measured values for fetal fraction unbound (fu = 0.108) or on values predicted by the simulator (fu = 0.044). Adequate doses were predicted according to the efficacy target of 15 ng/mL (or 38 ng/mL) and safety target of 166 ng/mL (or 409 ng/mL), assuming measured (or predicted) fu values, respectively. Considering simulated median profiles for average steady state sildenafil concentrations, dosing regimens of 130 mg/day or 150 mg/day (administered as t.i.d.), were within the therapeutic window, assuming either measured or predicted fu values, respectively. For safety reasons, dosing should be initiated at 130 mg/day, under therapeutic drug monitoring. Additional experimental measurements should be performed to confirm accurate fetal (and maternal) values for fu. Additional characterization of pharmacodynamics in this specific population is required and may lead to further optimization of the dosing regimen.

14.
Nutr Cancer ; 63(4): 593-9, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21526453

RESUMO

Aberrant crypt foci (ACF) and colon rectal mucosal epithelial cell proliferation have been shown to be increased in patients with colon cancer and have been largely used for early detection of factors that influence colorectal carcinogenesis in rats. Fifty male Wistar rats were randomly divided into 5 groups. The groups G1 to G4 were given 4 injections of the carcinogen 1,2-dimethylhydrazine (DMH). The G2 group received Lychnophora ericoides (LE) extracts for 6 wk. The groups G3 and G4 received LE for 4 wk and 2 wk, respectively, at the postinitiation and initiation phases of colonic carcinogenesis. The group G5 was the control. Forty-two days after the first injections of DMH for the neoplasic induction, we observed a statistically significant decrease in the number of aberrant crypt foci (ACF) and an attenuation of the increase in cell proliferation induced by DMH in all the LE-treated groups. Thus, we concluded that Lychnophora ericoides extracts were effective against the development of cancer. These data suggest that LE has a protective influence on the process of colon carcinogenesis, suppressing both the initiation and the promotion of colonic carcinogenesis.


Assuntos
Focos de Criptas Aberrantes/tratamento farmacológico , Anticarcinógenos/farmacologia , Fitoterapia , Extratos Vegetais/farmacologia , Lesões Pré-Cancerosas , 1,2-Dimetilidrazina/toxicidade , Focos de Criptas Aberrantes/induzido quimicamente , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Arnica/química , Carcinógenos/toxicidade , Proliferação de Células , Cromatografia Líquida de Alta Pressão , Neoplasias do Colo/induzido quimicamente , Neoplasias do Colo/tratamento farmacológico , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Mucosa Intestinal , Masculino , Neoplasias Experimentais/induzido quimicamente , Neoplasias Experimentais/tratamento farmacológico , Ratos , Ratos Wistar
15.
J Trop Pediatr ; 56(2): 125-7, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19401408

RESUMO

A cross-sectional study was carried out over a period of 12 months to investigate the occurrence of human bocavirus (HBoV) infection in infants hospitalized for respiratory infections in a teaching hospital in Salvador, Brazil, and to describe the clinical manifestations of this infection. Nasopharyngeal aspirates were collected from the children and immunofluorescence and polymerase chain reaction were performed to investigate the presence of respiratory viruses. HBoV was detected in 4 out of 66 patients. Two of the HBoV-positive infants were co-infected with other viruses. The principal clinical findings in HBoV-positive children were: nasal obstruction, catarrh, cough, fever and dyspnea. This study revealed HBoV infection in children aged <2 months, suggesting that the infection may occur at a very early age.


Assuntos
Bocavirus Humano/isolamento & purificação , Infecções por Parvoviridae/diagnóstico , Infecções Respiratórias/diagnóstico , Doença Aguda , Brasil/epidemiologia , Estudos Transversais , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Hospitalização , Bocavirus Humano/genética , Humanos , Lactente , Recém-Nascido , Masculino , Dados de Sequência Molecular , Nasofaringe/virologia , Infecções por Parvoviridae/epidemiologia , Infecções por Parvoviridae/etiologia , Infecções por Parvoviridae/virologia , Reação em Cadeia da Polimerase , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/etiologia , Infecções Respiratórias/virologia , Inquéritos e Questionários
16.
Eur J Pharm Sci ; 142: 105081, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31669384

RESUMO

Bromopride is a prokinetic and antiemetic drug used to treat nausea and vomiting. Although its prescription is common in Brazil, there is a lack of studies about bromopride pharmacokinetics. Therefore, the aims of this study were to investigate the population pharmacokinetics of bromopride and to evaluate the influence of covariates on its absorption. This study is a retrospective analysis of data collected from bioequivalence studies. The data was modeled using MONOLIX 2018R2. Assuming one-compartment and linear elimination, the absorption phase was evaluated with different structural models. The model of sequential first- and zero-order with combined error and exponential inter-individual variability in all parameters best described the atypical absorption profile of bromopride. Population estimates were first-order absorption rate (ka) of 0.08 h - 1, fraction of dose absorbed by first-order (Fr) of 32.60%, duration of the zero-order absorption (Tk0) of 0.88 h with latency time (Tlag) of 0.47 h, volume of distribution of 230 l and clearance of 46.80 l h - 1. Bodyweight affects Tk0, dosage form was found to correlate with Tk0 and Tlag, while gender affects Tlag. However, simulations evaluating the clinical importance of these covariates on steady-state indicated minimal changes on bromopride exposure. The mixed absorption model was reasonable to describe the absorption process of bromopride because it had the flexibility to fit multiple-peaks profile and shows good agreement with physicochemical properties of drug.


Assuntos
Antieméticos/farmacocinética , Absorção Gastrointestinal/fisiologia , Metoclopramida/análogos & derivados , Administração Oral , Adulto , Disponibilidade Biológica , Brasil , Feminino , Humanos , Cinética , Masculino , Metoclopramida/farmacocinética , Estudos Retrospectivos
18.
Anal Bioanal Chem ; 391(2): 625-32, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18418586

RESUMO

The interaction of ten natural polyphenolic compounds (chlorogenic acid, apigenin, catechin, epicatechin, flavanone, flavone, quercetin, rutin, vicenin-2 and vitexin) with human serum albumin and mixtures of human serum albumin and α(1)-acid glycoprotein under near physiological conditions is studied by capillary electrophoresis-frontal analysis. Furthermore, the binding of these polyphenolic compounds to total plasmatic proteins is evaluated using ultrafiltration and capillary electrophoresis. In spite of the relatively small differences in the chemical structures of the compounds studied, large differences were observed in their binding behaviours to plasmatic proteins. The hydrophobicity, the presence/absence of some functional groups, steric hindrance and spatial arrangement seem to be key factors in the affinity of natural polyphenols towards plasmatic proteins.


Assuntos
Eletroforese Capilar/métodos , Flavonoides/metabolismo , Orosomucoide/metabolismo , Fenóis/metabolismo , Albumina Sérica/metabolismo , Flavonoides/química , Humanos , Orosomucoide/química , Fenóis/química , Polifenóis , Ligação Proteica
19.
J Ethnopharmacol ; 118(1): 86-93, 2008 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-18485638

RESUMO

Teas of Bidens pilosa and Mikania glomerata are popularly consumed to medicinal ends. The capacity to induce DNA damages and mutagenic effects of these teas were evaluated, in vitro, on HTC cells, with comet assay and micronucleus test. The teas tested at various doses were prepared differently: infusion of Mikania glomerata (IM) and Bidens pilosa (IB), macerate of Mikania glomerata in 80% ethanol (MM80) and decoction of Bidens pilosa (DB). In IM and MM80, the quantity of coumarin was determined by high-performance liquid chromatography (HPLC) with UV detection. Methylmethanesulfonate was utilized as positive control, phosphate-buffered saline as negative control, 80% ethanol as solvent control and 2-aminoanthracene as drug metabolism control. The comet assay demonstrated genotoxic effects for both plants. The genotoxic potential of IB was upper than DB, showing dose-response. In the MN test, excepting IM 40 microL/mL, all treatments was not mutagenic. The effects did not show direct relation with cumarin quantity present in IM and MM80. The results demonstrated DNA damages at the highest concentrations of alcoholic macerate (10 and 20 microL/mL) and infusion of Mikania glomerata (20 and 40 microL/mL) and of Bidens pilosa infusion (40 microL/mL). Thus, both dose and preparation-form suggest caution in the phytotherapeutic use of these plants.


Assuntos
Bidens/toxicidade , Mikania/toxicidade , Mutagênicos/toxicidade , Chá/toxicidade , Animais , Bidens/química , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Ensaio Cometa/métodos , Cumarínicos/administração & dosagem , Cumarínicos/isolamento & purificação , Cumarínicos/toxicidade , Relação Dose-Resposta a Droga , Neoplasias Hepáticas/metabolismo , Testes para Micronúcleos/métodos , Mikania/química , Mutagênicos/administração & dosagem , Mutagênicos/isolamento & purificação , Ratos , Chá/química
20.
Cad Saude Publica ; 24(5): 1062-70, 2008 May.
Artigo em Português | MEDLINE | ID: mdl-18461235

RESUMO

This cross-sectional study enrolled 97 inpatients at a teaching hospital in Salvador, Bahia, Brazil, to determine breastfeeding prevalence in infants less than 4 months of age hospitalized due to respiratory infection, and to evaluate the impact of hospitalization on breastfeeding. Patients' mothers were interviewed, and a standardized questionnaire was completed. After hospital discharge, medical records were reviewed and information on the infant's feeding practices during hospitalization was recorded. Exclusive breastfeeding was observed in 57.1% of patients, but it was interrupted in 35.4%, with the introduction of infant formula during hospitalization. Mean duration was not associated with the introduction of complementary feeding in the hospital. In the bivariate analysis, early interruption of exclusive breastfeeding was associated with higher maternal schooling and lower family income. Prevalence of exclusive breastfeeding was low. Hospitalization contributed to early interruption of exclusive breastfeeding in 35.4% of infants, possibly due to inadequate hospital infrastructure and insufficient support from health professionals to maintain exclusive breastfeeding.


Assuntos
Aleitamento Materno/estatística & dados numéricos , Hospitalização , Adulto , Brasil , Estudos Transversais , Escolaridade , Feminino , Hospitais Pediátricos , Humanos , Renda , Lactente , Recém-Nascido , Fatores de Tempo , Desmame
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