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1.
Heliyon ; 10(4): e26422, 2024 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-38434013

RESUMEN

Study objective: Kidney neoplasms have a high incidence, and radical nephrectomy or partial nephrectomy are the main treatment options. Our study aims to investigate the use of ultrasound-guided erector spinae plane block for perioperative analgesia in patients undergoing laparoscopic nephrectomy surgery. Design: Prospective, randomized, double-blind. Setting: University hospital. Patients: Our study included 50 patients (ASA I-III) who underwent laparoscopic nephrectomy at the hospital of Second Affiliated Hospital of Army Medical University. Interventions: The patients were divided into two groups: the ESPB group and the control group. In the ESPB group, a mixture of 10 mL of 1% lidocaine, 10 mL of 0.7% ropivacaine, 0.5 µg/kg dexmedetomidine, and 5 mg of dexamethasone was administered. In the control group, 20 mL of 0.9% saline was administered. Measurements: The primary outcome measure was the total consumption of sufentanil during the intraoperative period. Secondary outcome measures included visual analogue scale (VAS) pain scores at rest and during coughing at 1 h, 6 h, 12 h, 24 h, and 48 h postoperatively, intraoperative consumption of remifentanil, frequency of rescue analgesic administration, consumption of rescue analgesia and incidence of postoperative nausea and vomiting within 48 h. Results: The ESPB group exhibited lower intraoperative consumption of sufentanil, lower consumption of rescue analgesia, as well as VAS scores at rest and during coughing within the first 24 h postoperatively, compared to the control group. However, no significant differences were observed in VAS scores at 48 h postoperatively, postoperative nausea and vomiting, or the need for postoperative rescue analgesia. Conclusions: Ultrasound-guided ESPB performed in patients who underwent laparoscopic nephrectomy demonstrated a substantial decrease in intraoperative opioid consumption, as well as lower VAS scores at rest and during coughing in the postoperative period.

2.
J Cardiothorac Vasc Anesth ; 38(5): 1169-1180, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38423886

RESUMEN

OBJECTIVES: The authors sought to elucidate the role and predictive effects of preoperative nutritional status on postoperative outcomes across different age groups undergoing heart valve surgery. DESIGN: A retrospective study with intergroup comparison, receiver operating characteristic curve analysis, and logistic regression analysis. SETTING: A hospital affiliated with a medical university. PARTICIPANTS: Three thousand nine hundred five patients undergoing heart valve surgery between October 2016 and December 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were categorized into 3 age subgroups: young (aged 18-44 years), middle-aged (aged 45-59 years), and older (aged ≥60 years) adults. The Nutritional Risk Index (NRI), Prognostic Nutritional Index, and Controlling Nutritional Status scores were evaluated. Young adults with an NRI <99 experienced a significantly higher rate of prolonged intensive care unit stay (28.3% v 4.1%, p < 0.001), with a relative risk of 4.58 (95% CI: 2.04-10.27). Similarly, young adults with an NRI <97 had a significantly increased occurrence of mortality within 30 days after surgery (6.3% v 0.2%, p < 0.001), with a relative risk of 41.11 (95% CI: 3.19-529.48). CONCLUSIONS: In patients who undergo heart valve surgery, early postoperative outcomes can be influenced by nutritional status before the surgery. In the young-adult group, NRI <99 and NRI <97 effectively could predict prolonged intensive care unit stay and 30-day mortality, respectively.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Estado Nutricional , Persona de Mediana Edad , Humanos , Estudios Retrospectivos , Factores de Riesgo , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Válvulas Cardíacas/cirugía , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/epidemiología
3.
Trials ; 25(1): 10, 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38167138

RESUMEN

BACKGROUND: Laparoscopic nephrectomy is a commonly utilized surgical approach for the management of renal cancer. Despite its widespread acceptance, postoperative pain management remains a significant challenge for many patients undergoing this procedure. Traditional pain management techniques, including opioid and nonsteroidal anti-inflammatory drug administration, may not provide adequate pain relief and may result in adverse effects. In recent years, erector spinae plane block (ESPB) has emerged as a promising regional anesthesia technique due to its simplicity, safety, and potential efficacy in reducing postoperative pain. ESPB has demonstrated effectiveness in reducing postoperative pain in various surgical procedures. However, the efficacy of ESPB in laparoscopic nephrectomy for renal cancer has not been extensively studied. As such, further investigation is necessary to determine the potential benefits of ESPB in this context. The addition of adjuvants such as dexmedetomidine and dexamethasone to nerve blocks has been shown to improve both the duration and quality of the block. Multiple studies have demonstrated the safety and efficacy of these adjuvants in reducing postoperative pain and opioid consumption and improving patient satisfaction. The use of dexmedetomidine and dexamethasone as adjuvants for nerve blocks represents a promising approach for enhancing regional anesthesia and analgesia. In light of these findings, we have incorporated dexmedetomidine and dexamethasone into our nerve block protocol. METHODS: This study is a randomized controlled trial conducted at a single center, with 50 participants being randomized in a 1:1 ratio to either the ESPB group or the control group. The trial aims to investigate the efficacy of ESPB in patients diagnosed with kidney cancer who are scheduled for laparoscopic nephrectomy. The primary outcome measure is the total consumption of intraoperative sufentanil. Secondary outcomes include the VAS score at rest and during coughing at 1 h, 6 h, 12 h, 24 h, and 48 h after surgery; total intraoperative remifentanil consumption; the number of times rescue analgesia is required; and the incidence of nausea and vomiting in the first 24 h after surgery. This study is registered for a duration of 1 year and is being conducted in China. DISCUSSION: The objective of our study is to evaluate the potential benefits of erector spinae plane block (ESPB) in patients undergoing laparoscopic nephrectomy, with a focus on the impact of dexmedetomidine and dexamethasone as adjuvants on the quality and duration of the block, as well as postoperative pain and opioid consumption. By investigating the effects of these adjuvants in the context of ESPB, we hope to contribute to the growing body of literature on the use of adjuvants in nerve blocks and provide further insight into the potential benefits of this approach for improving patient outcomes following laparoscopic nephrectomy. This trial was approved by the Ethics Committee of the Second Affiliated Hospital of Army Medical University. TRIAL REGISTRATION: China Clinical Trial Register ChiCTR2300068578 . Registered on 20 February 2023.


Asunto(s)
Analgesia , Anestesia de Conducción , Carcinoma de Células Renales , Dexmedetomidina , Neoplasias Renales , Laparoscopía , Bloqueo Nervioso , Humanos , Analgésicos Opioides , Nefrectomía/efectos adversos , Bloqueo Nervioso/efectos adversos , Dolor Postoperatorio/diagnóstico , Dolor Postoperatorio/etiología , Dolor Postoperatorio/prevención & control , Adyuvantes Inmunológicos , Carcinoma de Células Renales/cirugía , Neoplasias Renales/cirugía , Laparoscopía/efectos adversos , Ultrasonografía Intervencional , Dexametasona
4.
Sci Rep ; 13(1): 18166, 2023 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-37875560

RESUMEN

Structural topology optimization has gained widespread attention due to more possibilities of innovative structural design. The current research focus/hotspots, application areas, main research scholars, institutions and the countries involved in structural topology optimization are visually presented through clustering and visual analysis based on CiteSpace. The four metric dimensions of the literatures in this paper are as follows: annual quantity of papers and core countries, core authors and co-authors' institutions, hotspots and burst terms, and the highly co-cited papers. The results show the research hotspots in this field are concentrated on keywords such as "level set method", "sensitivity analysis", "homogenization", "genetic algorithm", etc. Regarding the research frontier, "moving morphable component (MMC)", "additive manufacturing (AM)" and "deep learning" are hot topics. In addition, Y. Sui, Z. Kang and O. Sigmund, etc. have high publications. M. Bendsøe and O. Sigmund have high citations. Dalian University of Technology, Technical University of Denmark, etc. are prominent institutions. Moreover, China accounts for more than 34% in the terms of original WOS literatures following by the USA and Australia. This paper could identify structural topology optimization development patterns for the scholars concerned with this field, especially novices, to quickly focus and track the research priorities.

5.
PLoS One ; 18(8): e0290952, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37651400

RESUMEN

The efficient allocation of sports resources for optimal outcomes remains a pressing national endeavour in China. Over the past two decades, substantial investments by provincial and national governments have been directed toward sports infrastructure development. This initiative aims to foster sports talent, facilitate excellence, host major sporting events, and enhance national pride and soft power. This study employs a comprehensive methodology encompassing Data Envelopment Analysis-Slack Based Measure (DEA-SBM), Meta Frontier Analysis, and Malmquist Productivity Index to assess Sports Resource Utilization Efficiency (SRUE), Technological Gap Ratio (TGR), and Productivity Growth (MI) across China's 31 provinces and 3 distinct regions for the period 2010-2021. The findings indicate that China's average SRUE stands at 0.6307, revealing an inefficiency of 36.93% in sports resource utilization. Noteworthy efficiency was observed in Beijing, Chongqing, Henan, Shaanxi, Shanghai, and Tianjin during the study duration. Furthermore, a consistent upward trajectory in SRUE from 2010 to 2021 highlights gradual and sustained progress. Comparatively, the eastern region showcases higher technological advancement (average TGR of 0.7598) than the central and western regions. The Malmquist Productivity Index (MI), with an average value of 1.05391, highlights a substantial 5.39% productivity growth. Notably, technological advancement emerges as the primary driver of this productivity increase, evident through the higher Total Factor Productivity Change (TC) of 1.0312 compared to the Efficiency Change (EC) of 1.0209. The Central region's outperforming productivity growth is noteworthy relative to the Eastern and Western regions. Conclusively, the Kruskal-Wallis test confirms significant disparities in the average MI, EC, TC, and TGR among all three regions of China.


Asunto(s)
Inversiones en Salud , Deportes , Beijing , China , Tecnología
6.
Front Immunol ; 14: 1159089, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37063874

RESUMEN

Introduction: Preoperative inflammation affects the postoperative outcomes of patients undergoing heart valve surgery. This study aimed to explore the role and predictive effects of preoperative inflammation on the primary outcomes after valvular cardiac surgery. Methods: This retrospective study utilized a medical recording system to screen 5075 patients who underwent heart valve surgery. Data on the C-reactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), and neutrophil-to-lymphocyte ratio (NLR) before heart valve surgery were collected from the hospital's medical system. Postoperative hepatic insufficiency, acute kidney injury, heart failure, and myocardial damage were assessed using blood indicators. Patients with and without prolonged mechanical ventilation, extended intensive care unit stays, prolonged hospital stays, and death within 30 days after surgery (considered the primary outcome in this study) were compared. Group comparisons, receiver operating characteristic (ROC) curve analyses, and logistic analyses were performed to determine the associations between preoperative inflammation and outcomes after heart valve surgery. Results: A total of 3249 patients were included in the analysis. Significant differences in CRP level, ESR, and NLR were found between patients with and without postoperative adverse outcomes. ROC analysis showed that CRP levels >5 mg/L effectively predicted postoperative heart failure, and NLR >3.5 had a good predictive effect on all-cause mortality within 30 days after surgery. Patients with CRP levels >5 mg/L had a higher incidence of postoperative heart failure than other patients (20.7% vs. 12.6%, P<0.001), with a relative risk of 1.447 (95% confidence interval: 1.155-1.814). Patients with NLR >3.5 had a higher incidence of death within 30 days after surgery (5.3% vs. 1.2%, P<0.001), with a relative risk of 3.236 (95% confidence interval: 1.773-5.906). Conclusion: Preoperative inflammation can affect postoperative outcomes in patients undergoing heart valve surgery. CRP level >5 mg/L and NLR >3.5 can effectively predict postoperative heart failure and death within 30 days after surgery, respectively.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Insuficiencia Cardíaca , Humanos , Estudios Retrospectivos , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Válvulas Cardíacas , Inflamación
7.
Front Psychol ; 14: 1104349, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37008843

RESUMEN

The rapid development of livestreaming commerce has received widespread attention from both theoretical and practical circles. However, relatively few studies have been conducted from a product perspective, and even fewer studies have analyzed product characteristics influencing consumers' impulse buying based on product-involvement theory. Grounded on product involvement theory, this study proposed a theoretical research model and empirically tested the model using online survey data collected from 504 livestreaming consumers in China. The results showed that functional value for money, perceived product quality, perceived product scarcity, instant feedback on product information, and perceived product knowledge of streamers can drive product cognitive and affective involvement, which, in turn, induce the consumer-felt urge to buy impulsively and engage in impulse buying behavior. However, the functionality of product design can only affect the product cognitive involvement, not the affective involvement. Implications for research and practice are discussed.

8.
Front Plant Sci ; 13: 916900, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35769290

RESUMEN

Forest succession analysis can predict forest change trends in the study area, which provides an important basis for other studies. Remote sensing is a recognized and effective tool in forestry succession analysis. Many forest modeling studies use statistic values, but only a few uses remote sensing images. In this study, we propose a machine learning-based digital twin approach for forestry. A data processing algorithm was designed to process Landsat 7 remote sensing data as model's input. An LSTM-based model was constructed to fit historical image data of the study area. The experimental results show that this study's digital twin method can effectively forecast the study area's future image.

9.
Appl Opt ; 57(18): 5130-5140, 2018 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-30117975

RESUMEN

Precise calibration of a binocular vision system is the foundation of binocular vision measurement. In this paper, we propose a highly precise and robust binocular camera calibration method, which is devoted to minimize the error between the geometric relation of 3D reconstructed feature points and the ground truth, such as adjacent distance error, collinear error, and right-angle error. In addition, the reprojection error and epipolar are introduced to satisfy the homography relation and epipolar geometry theory better. We optimize all intrinsic parameters, extrinsic parameters, and distortion parameters to minimize the objective function, which is the sum of a series of nonlinear least squares terms. Levenberg-Marquardt iterative algorithm is used to find the optimal solution of the camera parameters. To test the precision and robustness of the proposed method, both actual measurement experiments and Gauss noise-adding experiments are carried out. The experimental results show that compared with the other two calibration methods in the contrast experiment, the distance measurement error, collinear error, and right-angle error are reduced dramatically. It is noticeable that in Gauss noise-adding experiments, the calibration parameters estimated by the proposed method are more stable.

10.
Proteome Sci ; 7: 38, 2009 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-19814785

RESUMEN

BACKGROUND: Two-dimensional gel electrophoresis (2-DE) is a powerful method to study protein expression and function in living organisms and diseases. This technique, however, has not been applied to avian bursa of Fabricius (BF), a central immune organ. Here, optimized 2-DE sample preparation methodologies were constructed for the chicken BF tissue. Using the optimized protocol, we performed further 2-DE analysis on a soluble protein extract from the BF of chickens infected with virulent avibirnavirus. To demonstrate the quality of the extracted proteins, several differentially expressed protein spots selected were cut from 2-DE gels and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). RESULTS: An extraction buffer containing 7 M urea, 2 M thiourea, 2% (w/v) 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS), 50 mM dithiothreitol (DTT), 0.2% Bio-Lyte 3/10, 1 mM phenylmethylsulfonyl fluoride (PMSF), 20 U/ml Deoxyribonuclease I (DNase I), and 0.25 mg/ml Ribonuclease A (RNase A), combined with sonication and vortex, yielded the best 2-DE data. Relative to non-frozen immobilized pH gradient (IPG) strips, frozen IPG strips did not result in significant changes in the 2-DE patterns after isoelectric focusing (IEF). When the optimized protocol was used to analyze the spleen and thymus, as well as avibirnavirus-infected bursa, high quality 2-DE protein expression profiles were obtained. 2-DE maps of BF of chickens infected with virulent avibirnavirus were visibly different and many differentially expressed proteins were found. CONCLUSION: These results showed that method C, in concert extraction buffer IV, was the most favorable for preparing samples for IEF and subsequent protein separation and yielded the best quality 2-DE patterns. The optimized protocol is a useful sample preparation method for comparative proteomics analysis of chicken BF tissues.

11.
J Virol ; 83(17): 8957-64, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19553321

RESUMEN

The highly pathogenic H5N1 avian influenza virus emerged from China in 1996 and has spread across Eurasia and Africa, with a continuous stream of new cases of human infection appearing since the first large-scale outbreak among migratory birds at Qinghai Lake. The role of wild birds, which are the natural reservoirs for the virus, in the epidemiology of the H5N1 virus has raised great public health concern, but their role in the spread of the virus within the natural ecosystem of free-ranging terrestrial wild mammals remains unclear. In this study, we investigated H5N1 virus infection in wild pikas in an attempt to trace the circulation of the virus. Seroepidemiological surveys confirmed a natural H5N1 virus infection of wild pikas in their native environment. The hemagglutination gene of the H5N1 virus isolated from pikas reveals two distinct evolutionary clades, a mixed/Vietnam H5N1 virus sublineage (MV-like pika virus) and a wild bird Qinghai (QH)-like H5N1 virus sublineage (QH-like pika virus). The amino acid residue (glutamic acid) at position 627 encoded by the PB2 gene of the MV-like pika virus was different from that of the QH-like pika virus; the residue of the MV-like pika virus was the same as that of the goose H5N1 virus (A/GS/Guangdong [GD]/1/96). Further, we discovered that in contrast to the MV-like pika virus, which is nonpathogenic to mice, the QH-like pika virus is highly pathogenic. To mimic the virus infection of pikas, we intranasally inoculated rabbits, a species closely related to pikas, with the H5N1 virus of pika origin. Our findings first demonstrate that wild pikas are mammalian hosts exposed to H5N1 subtype avian influenza viruses in the natural ecosystem and also imply a potential transmission of highly pathogenic avian influenza virus from wild mammals into domestic mammalian hosts and humans.


Asunto(s)
Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Lagomorpha/virología , Infecciones por Orthomyxoviridae/veterinaria , Animales , China , Análisis por Conglomerados , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Ratones , Epidemiología Molecular , Datos de Secuencia Molecular , Infecciones por Orthomyxoviridae/epidemiología , Infecciones por Orthomyxoviridae/virología , Filogenia , ARN Polimerasa Dependiente del ARN/genética , Conejos , Análisis de Secuencia de ADN , Homología de Secuencia , Estudios Seroepidemiológicos , Proteínas Virales/genética
12.
DNA Cell Biol ; 28(1): 23-9, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19072659

RESUMEN

The replication-associated (Rep) protein of porcine circovirus (PCV) was suggested to play an essential role in the replication and translation of viral DNA. In this study, one monoclonal antibody (mAb) specific for Rep protein of porcine circovirus type 1 (PCV1), two mAbs against Rep protein of porcine circovirus type 2 (PCV2), and five mAbs to both Rep protein of PCV1 and PCV2 were generated using, respectively, Rep protein of PCV1 and PCV2 expressed in Escherichia coli as an immunogen. Western blot analysis showed that native Rep protein of PCV2 virions appeared in two forms with different molecular weight in PCV2-infected cells. Laser confocal analyses further exhibited that Rep protein distributed mainly in the cellular nucleoplasm at the early stage of PCV2 infection, and moved to the nuclear periphery and the cytoplasm at the last stage of PCV2 infection. The results from this study confirmed that Rep protein of PCV2 distributed in both nucleus and cytoplasm, and provided an mAb tool to further analyze replications of PCV1 and PCV2 in vitro and in vivo.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Circovirus/inmunología , Proteínas Reguladoras y Accesorias Virales/inmunología , Animales , Especificidad de Anticuerpos/inmunología , Western Blotting , Línea Celular , Núcleo Celular/metabolismo , Circovirus/genética , Circovirus/metabolismo , Reacciones Cruzadas/inmunología , Citoplasma/metabolismo , Células Epiteliales/metabolismo , Células Epiteliales/virología , Mapeo Epitopo , Inmunoglobulina G/inmunología , Ratones , Ratones Endogámicos BALB C , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Porcinos , Proteínas Reguladoras y Accesorias Virales/biosíntesis , Proteínas Reguladoras y Accesorias Virales/genética , Proteínas Reguladoras y Accesorias Virales/metabolismo
13.
Mol Immunol ; 46(3): 327-34, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19059648

RESUMEN

Type 2 porcine circovirus (PCV2) is associated with post-weaning multisystemic wasting syndrome in pigs. In this study, three monoclonal antibodies (mAbs) against the capsid protein (Cap) of PCV2, eight mAbs to Cap of type 1 porcine circovirus (PCV1) and five mAbs specific for Cap of both PCV1 and PCV2, were generated and used to finely map the antigenic sites of PCV1 and PCV2, and to identify the antigenic phenotype of PCV2 with different length of genome. Five linear B-cell epitopes, including the residues 231-233 and 195-202 specific for PCV2, residues 92-103 specific for PCV1, and residues 156-162 and 175-192 shared between PCV1 and PCV2, were finely defined with synthetic peptides, and the critical residue in epitope 231-233 and 156-162 was located at residues 233 ((233)Proline) and 156 ((156)Tyrosine), respectively. The conformational epitopes recognized by mAbs with neutralizing activity against both PCV1 and PCV2 were detected in transfected PK-15 and the residues 231-233 also participated in the formation of conformational epitopes. Analysis of antigenic diversity on these epitopes exhibited three antigenic phenotypes of PCV2, (1766)PCV2, (1767)PCV2 and (1768)PCV2 using mAbs. The results from this study first demonstrated the different antigenic phenotype between PCV2 isolates.


Asunto(s)
Antígenos Virales/inmunología , Proteínas de la Cápside/química , Proteínas de la Cápside/inmunología , Circovirus/química , Circovirus/inmunología , Mapeo Epitopo , Epítopos/inmunología , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales/inmunología , Formación de Anticuerpos , Antígenos Virales/química , Línea Celular , Infecciones por Circoviridae/inmunología , Circovirus/aislamiento & purificación , Ensayo de Inmunoadsorción Enzimática , Epítopos/química , Genoma , Cinética , Ratones , Datos de Secuencia Molecular , Pruebas de Neutralización , Fenotipo , Conformación Proteica , Sus scrofa , Transfección
14.
J Pharm Sci ; 97(1): 263-73, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17803198

RESUMEN

The objective of this work was to develop and evaluate a floating-pulsatile drug delivery system intended for chronopharmacotherapy. Floating-pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. To overcome limitations of various approaches for imparting buoyancy, we generated the system which consisted of three different parts, a core tablet, containing the active ingredient, an erodible outer shell and a top cover buoyant layer. The dry coated tablet consists in a drug-containing core, coated by a hydrophilic erodible polymer which is responsible for a lag phase in the onset of pulsatile release. The buoyant layer, prepared with Methocel K4M, Carbopol 934P and sodium bicarbonate, provides buoyancy to increase the retention of the oral dosage form in the stomach. The effect of the hydrophilic erodible polymer characteristics on the lag time and drug release was investigated. Developed formulations were evaluated for their buoyancy, dissolution and pharmacokinetic, as well gamma-scintigraphically. The results showed that a certain lag time before the drug released generally due to the erosion of the dry coated layer. Floating time was controlled by the quantity and composition of the buoyant layer. Both pharmacokinetic and gamma-scintigraphic data point out the capability of the system of prolonged residence of the tablets in the stomach and releasing drugs after a programmed lag time.


Asunto(s)
Sistemas de Liberación de Medicamentos , Adulto , Animales , Fenómenos Químicos , Química Farmacéutica , Química Física , Cromatografía Líquida de Alta Presión , Preparaciones de Acción Retardada , Perros , Diseño de Fármacos , Excipientes , Vaciamiento Gástrico , Humanos , Derivados de la Hipromelosa , Marcaje Isotópico , Masculino , Metilcelulosa/análogos & derivados , Preparaciones Farmacéuticas/administración & dosificación , Preparaciones Farmacéuticas/metabolismo , Farmacocinética , Solubilidad , Comprimidos , Tecnecio
15.
Chem Pharm Bull (Tokyo) ; 55(4): 580-5, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17409552

RESUMEN

A blend of floating and pulsatile principles of drug delivery system seems to present the advantage that a drug can be released in the upper GI tract after a definite time period of no drug release. The objective of this study was to develop and evaluate a floating and pulsatile drug delivery system based on an impermeable cylinder. Pulsatile capsule was prepared by sealing the drug tablet and the buoyant material filler inside the impermeable capsule body with erodible plug. The drug delivery system showed typical floating and pulsatile release profile with a lag time followed by a rapid release phase. The lag time prior to the pulsatile drug release correlated well with the erosion properties of plugs and the composition of the plug could be controlled by the weight of the plug. The buoyancy of the whole system depended on the bulk density of the dosage form. Gamma-scintigraphic evaluation in humans was used to establish methodology capable of showing the subsequent in vivo performance of the floating and pulsatile release capsule. Developed formulations showed instantaneous floating with no drug release during the lag time followed by a pulse drug release. From the gamma-scintigraphic results, the pulsatile release capsule we prepared could achieve a rapid release after lag time in vivo, which was longer than that in vitro. The scintigraphic evaluation could confirm qualitatively that the system with in vitro lag time of 4.0 h provided, with relatively high reproducibility, a pulsatile release occurred around 5.0 h after administration.


Asunto(s)
Sistemas de Liberación de Medicamentos , Cintigrafía , Comprimidos
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