Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
1.
Endoscopy ; 52(5): 389-407, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32259849

RESUMO

The following recommendations should only be applied after a thorough diagnostic evaluation including a contrast-enhanced computed tomography (CT) scan. 1 : ESGE recommends colonic stenting to be reserved for patients with clinical symptoms and radiological signs of malignant large-bowel obstruction, without signs of perforation. ESGE does not recommend prophylactic stent placement.Strong recommendation, low quality evidence. 2 : ESGE recommends stenting as a bridge to surgery to be discussed, within a shared decision-making process, as a treatment option in patients with potentially curable left-sided obstructing colon cancer as an alternative to emergency resection.Strong recommendation, high quality evidence. 3 : ESGE recommends colonic stenting as the preferred treatment for palliation of malignant colonic obstruction.Strong recommendation, high quality evidence. 4 : ESGE suggests consideration of colonic stenting for malignant obstruction of the proximal colon either as a bridge to surgery or in a palliative setting.Weak recommendation, low quality evidence. 5 : ESGE suggests a time interval of approximately 2 weeks until resection when colonic stenting is performed as a bridge to elective surgery in patients with curable left-sided colon cancer.Weak recommendation, low quality evidence. 6 : ESGE recommends that colonic stenting should be performed or directly supervised by an operator who can demonstrate competence in both colonoscopy and fluoroscopic techniques and who performs colonic stenting on a regular basis.Strong recommendation, low quality evidence. 7 : ESGE suggests that a decompressing stoma as a bridge to elective surgery is a valid option if the patient is not a candidate for colonic stenting or when stenting expertise is not available.Weak recommendation, low quality evidence.


Assuntos
Neoplasias do Colo , Obstrução Intestinal , Stents Metálicos Autoexpansíveis , Neoplasias do Colo/complicações , Neoplasias do Colo/cirurgia , Colonoscopia , Endoscopia Gastrointestinal , Humanos , Obstrução Intestinal/etiologia , Obstrução Intestinal/cirurgia , Stents
2.
Gastrointest Endosc ; 87(3): 705-713.e2, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28579348

RESUMO

BACKGROUND AND AIMS: Self-expandable metal stents are used increasingly in the treatment of obstructing colorectal cancer (CRC). Although endoscopic colon stenting is widely accepted in palliation, disagreement exists about its role in a curative setting. This study aims to describe long-term survival data in a large patient group treated with colon stenting as a bridge to surgery for CRC. METHODS: This prospective study included 97 patients who presented in a Belgian hospital between 1998 and 2013 with obstructing, although potentially curable, CRC. All patients underwent endoscopic stenting as a bridge to surgery. Procedure-related adverse events and long-term follow-up data were retrospectively collected and compared with the CRC mortality in Belgium in the same time span. RESULTS: Overall survival in this observational cohort did not differ significantly from survival in all Belgian patients with CRC in the same period (P = .14). One-year, 5-year, and 10-year survival rates were similar in both groups (95.9% vs 79.0%; 54.7% vs 51.2%; 41.0% vs 35.6%, respectively). The technical success rate was 94.8%. Seventy-three patients did not experience any adverse event. Stent migration occurred in 9 patients, whereas micro-perforations and macro-perforations were observed in 14 patients, without influence on survival. Incidence rates of peritoneal metastases did not differ between patients with and without any type of perforation (22.2% vs 15.2%, respectively; P = .47). The type of stent influenced the overall adverse event risk, mainly driven by a significant increase in stent migration in case of Wallstent enteral (Boston Scientific Corporation, Natick, Mass). CONCLUSIONS: Colon stenting before surgery is effective and did not worsen the survival outcome in patients with obstructing CRC who were treated with curative intent, which affirms the role for stenting as a bridge to surgery.


Assuntos
Neoplasias do Colo/mortalidade , Colonoscopia/métodos , Obstrução Intestinal/cirurgia , Stents Metálicos Autoexpansíveis/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Bélgica , Colo/patologia , Colo/cirurgia , Neoplasias do Colo/complicações , Neoplasias do Colo/cirurgia , Colonoscopia/efeitos adversos , Feminino , Humanos , Obstrução Intestinal/etiologia , Obstrução Intestinal/mortalidade , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Sistema de Registros , Taxa de Sobrevida , Resultado do Tratamento
3.
Acta Gastroenterol Belg ; 80(3): 416-418, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29560673

RESUMO

We present two cases of patients with severe persistent diarrhoea, in whom duodenal biopsies revealed villous atrophy that could be attributed to the use of olmesartan. The differential diagnosis of villous atrophy without serological markers of celiac disease should include drugs as possible cause, with olmesartan as a recently discovered culprit. Gastroenterologist should be aware of this entity.


Assuntos
Diarreia , Duodeno/patologia , Imidazóis/efeitos adversos , Mucosa Intestinal , Microvilosidades/patologia , Tetrazóis/efeitos adversos , Idoso , Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Bloqueadores do Receptor Tipo 1 de Angiotensina II/efeitos adversos , Atrofia/induzido quimicamente , Atrofia/patologia , Biópsia/métodos , Diagnóstico Diferencial , Diarreia/diagnóstico , Diarreia/etiologia , Diarreia/fisiopatologia , Diarreia/terapia , Feminino , Humanos , Imidazóis/administração & dosagem , Mucosa Intestinal/ultraestrutura , Masculino , Tetrazóis/administração & dosagem , Resultado do Tratamento , Suspensão de Tratamento
5.
Endoscopy ; 46(11): 990-1053, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25325682

RESUMO

This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE). This Guideline was also reviewed and endorsed by the Governing Board of the American Society for Gastrointestinal Endoscopy (ASGE). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence. Main recommendations The following recommendations should only be applied after a thorough diagnostic evaluation including a contrast-enhanced computed tomography (CT) scan. 1 Prophylactic colonic stent placement is not recommended. Colonic stenting should be reserved for patients with clinical symptoms and imaging evidence of malignant large-bowel obstruction, without signs of perforation (strong recommendation, low quality evidence). 2 Colonic self-expandable metal stent (SEMS) placement as a bridge to elective surgery is not recommended as a standard treatment of symptomatic left-sided malignant colonic obstruction (strong recommendation, high quality evidence). 3 For patients with potentially curable but obstructing left-sided colonic cancer, stent placement may be considered as an alternative to emergency surgery in those who have an increased risk of postoperative mortality, I. e. American Society of Anesthesiologists (ASA) Physical Status ≥ III and/or age > 70 years (weak recommendation, low quality evidence). 4 SEMS placement is recommended as the preferred treatment for palliation of malignant colonic obstruction (strong recommendation, high quality evidence), except in patients treated or considered for treatment with antiangiogenic drugs (e. g. bevacizumab) (strong recommendation, low quality evidence).


Assuntos
Neoplasias do Colo/complicações , Obstrução Intestinal/terapia , Cuidados Paliativos/métodos , Stents , Colonoscopia , Humanos , Obstrução Intestinal/etiologia , Seleção de Pacientes , Implantação de Prótese/métodos
6.
Inflamm Bowel Dis ; 19(10): 2111-7, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23883959

RESUMO

BACKGROUND: This study examined whether fecal calprotectin can be used in daily practice as a marker to monitor patients with ulcerative colitis (UC) receiving infliximab maintenance therapy. METHODS: This prospective multicenter study enrolled adult patients with UC in clinical remission under infliximab maintenance therapy. Fecal calprotectin levels were measured every 4 weeks. Sigmoidoscopies were performed at inclusion and at study end. Relapse was defined as a clinical need for change in treatment or an endoscopic Mayo subscore of ≥2 at week 52. Sustained deep remission was defined as a partial Mayo score <3 at all points and an endoscopic Mayo score 0 at week 52. RESULTS: Full analysis was possible for 87 of 113 included patients with UC (77%). Of these patients, 30 (34.4%) were considered to be in sustained deep remission and 13 (14.9%) to have relapsed. Calprotectin levels in patients with sustained deep remission remained very low (median < 40 mg/kg at all time points). Patients who flared had significantly higher calprotectin levels (median > 300 mg/kg) already 3 months before the flare. Further receiver operator curve analysis suggested that a calprotectin level >300 mg/kg had a reasonable sensitivity (58.3%) and specificity (93.3%) to model flare. Two consecutive calprotectin measurements of >300 mg/kg with 1-month interval were identified as the best predictor of flare (61.5% sensitivity and 100% specificity). CONCLUSIONS: Fecal calprotectin can be used in daily practice to monitor patients with UC receiving infliximab maintenance therapy. Two consecutive measurements >300 mg/kg is more specific than a single measurement for predicting relapse.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Biomarcadores/metabolismo , Colite Ulcerativa/tratamento farmacológico , Fezes/química , Complexo Antígeno L1 Leucocitário/metabolismo , Adulto , Idoso , Área Sob a Curva , Colite Ulcerativa/complicações , Colite Ulcerativa/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Seguimentos , Humanos , Infliximab , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Recidiva , Indução de Remissão , Sigmoidoscopia , Adulto Jovem
7.
Gastroenterol Res Pract ; 2012: 296347, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22761609

RESUMO

Background. Self-expanding metal stents can alleviate malignant colonic obstruction in incurable patients and avoid palliative stoma surgery. Objective. Evaluate stent effectiveness and safety on palliation of patients with malignant colorectal strictures. Design. Two prospective, one Spanish and one global, multicenter studies. Settings. 39 centers (22 academic, 17 community hospitals) from 13 countries. Patients. A total of 257 patients were enrolled, and 255 patients were treated with a WallFlex uncovered enteral colonic stent. Follow-up was up to 12 months or until death or retreatment. Interventions(s). Self-expanding metal stent placement. Main Outcome Measures. Procedural success, clinical success, and safety. Results. Procedural success was 98.4% (251). Clinical success rates were 87.8% at 30 days, 89.7% at 3 months, 92.8% at 6 months, and 96% at 12 months. Overall perforation rate was 5.1%. Overall migration rate was 5.5%. Overall death rate during follow-up was 48.6% (124), with 67.7% of deaths related to the patient's colorectal cancer, unrelated in 32.3%. Only 2 deaths were related to the stent or procedure. Limitations. No control group. Conclusions. The primary palliative option for patients with malignant colonic obstruction should be self-expanding metal stent placement due to high rates of technical success and efficacy in symptom palliation and few complications.

8.
Gastrointest Endosc ; 74(4): 876-84, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21855868

RESUMO

BACKGROUND: The self-expandable metal stent (SEMS) can alleviate malignant colonic obstruction and avoid emergency decompressive surgery. OBJECTIVE: To document performance, safety, and effectiveness of colorectal stents used per local standards of practice in patients with malignant large-bowel obstruction to avoid palliative stoma surgery in incurable patients (PAL) and facilitate bowel decompression as a bridge to surgery for curable patients (BTS). DESIGN: Prospective clinical cohort study. SETTING: Two global registries with 39 academic and community centers. PATIENTS: This study involved 447 patients with malignant colonic obstruction who received stents (255 PAL, 182 BTS, 10 no indication specified). INTERVENTION: Colorectal through-the-scope SEMS placement. MAIN OUTCOME MEASUREMENTS: The primary endpoint was clinical success at 30 days, defined as the patient's ability to maintain bowel function without adverse events related to the procedure or stent. Secondary endpoints were procedural success, defined as successful stent placement in the correct position, symptoms of persistent or recurrent colonic obstruction, and complications. RESULTS: The procedural success rate was 94.8% (439/463), and the clinical success rates were 90.5% (313/346) as assessed on a per protocol basis and 71.6% (313/437) as assessed on an intent-to-treat basis. Complications included 15 (3.9%) perforations, 3 resulting in death, 7 (1.8%) migrations, 7 (1.8%) cases of pain, and 2 (0.5%) cases of bleeding. LIMITATIONS: No control group. No primary endpoint analysis data for 25% of patients. CONCLUSION: This largest multicenter, prospective study of colonic SEMS placement demonstrates that colonic SEMSs are safe and highly effective for the short-term treatment of malignant colorectal obstruction, allowing most curable patients to have 1-step resection without stoma and providing most incurable patients minimally invasive palliation instead of surgery. The risk of complications, including perforation, was low.


Assuntos
Neoplasias Colorretais/complicações , Obstrução Intestinal/terapia , Stents , Idoso , Colonoscopia , Neoplasias Colorretais/cirurgia , Feminino , Humanos , Obstrução Intestinal/etiologia , Perfuração Intestinal/etiologia , Masculino , Cuidados Paliativos , Stents/efeitos adversos
9.
J Control Release ; 151(3): 286-94, 2011 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-21241752

RESUMO

Dry eye syndrome is a common disorder of the tear film caused by decreased tear production or increased evaporation. The objective of this study was to evaluate the potential effectiveness of Cyclosporine A (CsA) nanoparticles (NPs) for the treatment of inflammation of the eye surface. Topical CsA is currently the only and safe pharmacologic treatment of severe dry eye symptoms. The NPs were prepared using either poly-lactide-co-glycolide (PLGA) or a mixture of PLGA with Eudragit®RL or were coated with Carbopol®. The mean size of CsA loaded NPs was within the range from 148 to 219nm, except for the Carbopol® coated NPs (393nm). The drug entrapment efficiency was very high (from 83 to 95%) and production yield was found between 75 and 92% in all preparations. The zeta potential of the Eudragit® RL containing NPs was positive (19-25mV). The NPs formulations exhibited a biphasic drug release with initial burst followed by a very slow drug release and total cumulative release within 24h ranged from 75 to 90%. Kinetically, the release profiles of CsA from NPs appeared to fit best with the Weibull model. The viability of L929 cells was decreased by increasing the concentration of the various NPs examined as well as the incubation time. The amount of NPs uptake was related to the polymer type used. The highest degree of cellular uptake (52.2%), tear film concentration of the drug (366.3ng/g) and AUC(0→24) (972.6ngh/g) value were obtained from PLGA: Eudragit® RL (75:25)-CsA NPs formulations. The change of surface characteristics of NPs represents a useful approach for improvement of ocular retention and drug availability.


Assuntos
Ciclosporina/administração & dosagem , Portadores de Fármacos/química , Olho/efeitos dos fármacos , Imunossupressores/administração & dosagem , Nanopartículas/química , Animais , Disponibilidade Biológica , Transporte Biológico , Técnicas de Cultura de Células , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ciclosporina/efeitos adversos , Ciclosporina/farmacocinética , Ciclosporina/uso terapêutico , Relação Dose-Resposta a Droga , Portadores de Fármacos/efeitos adversos , Composição de Medicamentos , Síndromes do Olho Seco/tratamento farmacológico , Síndromes do Olho Seco/metabolismo , Olho/metabolismo , Fibroblastos/efeitos dos fármacos , Imunossupressores/efeitos adversos , Imunossupressores/farmacocinética , Imunossupressores/uso terapêutico , Cinética , Masculino , Camundongos , Microscopia Eletrônica de Varredura , Nanopartículas/toxicidade , Tamanho da Partícula , Coelhos , Solubilidade , Propriedades de Superfície , Lágrimas/química
10.
Pharm Dev Technol ; 16(1): 29-35, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20038266

RESUMO

Pilocarpine loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by solvent evaporation method and coated with various mucoadhesive polymers, in particular chitosan, sodium alginate and poloxamers. The size of chitosan-coated nanoparticles was larger than the size of all the other particles obtained. Their surface charge was changed from negative (-22.8 mV) to positive (+61.0 mV). The interaction between mucin and chitosan-coated nanoparticles took place up to six hours according to turbidimetric study. The positive charge of chitosan-coated nanoparticles decreased significantly six hours after incubation in mucin dispersion, which was attributed to their electrostatic interaction. The coating with chitosan could be considered useful approach aiming to prolong nanoparticle residence time after local ocular application.


Assuntos
Portadores de Fármacos/química , Olho , Mucosa , Nanopartículas/química , Poliglactina 910/química , Adesividade , Administração Tópica , Cromatografia Líquida de Alta Pressão , Composição de Medicamentos , Olho/efeitos dos fármacos , Olho/metabolismo , Mucosa/efeitos dos fármacos , Mucosa/metabolismo , Tamanho da Partícula , Pilocarpina/administração & dosagem , Pilocarpina/química , Solubilidade , Eletricidade Estática , Propriedades de Superfície
12.
Front Biosci ; 13: 1711-5, 2008 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-17981662

RESUMO

The stratum corneum is the main barrier for transdermal drug transport. It could be bypassed by microneedles, which have a length of a few tens to a few hundreds of microns. They are usually arranged in arrays and can be used in several ways to enhance transdermal drug transport. Microneedles can be inserted into the skin in order to increase its permeability, after which the drug is applied (poke with patch). Drugs could also be coated onto the microneedles and be inserted into the skin (coat and poke). Hollow microneedles are used to inject drug solutions in to the skin. This review aims to discuss recently published in vivo and in vitro studies on microneedle aided transdermal drug delivery.


Assuntos
Administração Cutânea , Materiais Biocompatíveis/química , Sistemas de Liberação de Medicamentos , Injeções Intradérmicas/instrumentação , Injeções Intradérmicas/métodos , Microinjeções/métodos , Animais , Humanos , Microinjeções/tendências , Agulhas , Peptídeos/administração & dosagem , Pele , Absorção Cutânea , Tecnologia Farmacêutica/tendências , Vacinas/administração & dosagem
13.
Int J Pharm ; 349(1-2): 234-40, 2008 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-17888598

RESUMO

The aim of present study was to examine whether cationic Eudragit containing poly(lactide-co-glycolide) (PLGA) nanoparticles can adhere to Pseudomonas aeruginosa and Staphylococcus aureus. In order to prepare fluorescent nanoparticles, fluorescein was covalently coupled to PLGA. Fluorescent PLGA and Eudragit/PLGA nanoparticles were prepared by w/o/w emulsification solvent evaporation. Particle size and zeta potential of the nanoparticles were measured. Nanoparticles were incubated for a short time with P. aeruginosa and S. aureus followed by measurement of the size of nanoparticles and of P. aeruginosa and S. aureus with and without adherent nanoparticles. Flow cytometric measurements were performed to detect the attachment of particles to microorganisms. Eudragit containing nanoparticles possessed a positive zeta potential, while PLGA nanoparticles were negatively charged. Following adsorption of Eudragit containing nanoparticles, a size increase for P. aeruginosa was observed. Flow cytometric analyses confirmed that Eudragit containing particles showed stronger interactions with the test organisms than PLGA nanoparticles. Adhesion of particles was more pronounced for P. aeruginosa than for S. aureus. Cationic Eudragit containing nanoparticles showed better adhesion to microorganisms than anionic PLGA nanoparticles, which is probably due to enhanced electrostatic interactions.


Assuntos
Ácido Láctico , Ácido Poliglicólico , Polímeros , Ácidos Polimetacrílicos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Adesividade , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Fenômenos Químicos , Físico-Química , Ciprofloxacina/administração & dosagem , Ciprofloxacina/farmacologia , Eletroquímica , Citometria de Fluxo , Fluoresceínas , Corantes Fluorescentes , Nanopartículas , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico
14.
Planta Med ; 73(15): 1606-13, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18067064

RESUMO

Pueraria lobata, also known as Kudzu (Japan) or Ge (China), is a medicinal plant widely used in Oriental traditional medicine. In this study the development, optimization and validation of an HPLC ethod for quality control of Pueraria flower plant material is presented. By means of this analytical method the three major compounds, i. e., the isoflavones tectorigenin 7- O-[beta- D-xylopyranosyl-(1 - 6)-beta- D-glucopyranoside], tectorigenin 7- O-beta- D-glucopyranoside and tectorigenin, were quantified, using the isoflavones genistin and genistein as external standards. The extraction procedure, the extraction solvent, the extraction yields and the HPLC conditions were evaluated and optimized. The samples were analyzed on an RP C18 column, and eluted with a binary system consisting of water and methanol using a linear gradient; detection was at 262 nm. Tectorigenin used in the recovery experiments was isolated and purified in the laboratory. The final method was fully validated according to the ICH guidelines in terms of linearity, precision and accuracy. The validation data showed that the precision, (RSD% (betweendays) of 3.1, 2.84 and 1.77 for the three major compounds, respectively), and the accuracy (recovery of 104.2 %) were acceptable. These validation results demonstrate the suitability of the method for the quality control of this crude drug.


Assuntos
Fitoterapia/normas , Extratos Vegetais/química , Pueraria , Cromatografia Líquida de Alta Pressão , Flores , Humanos , Controle de Qualidade
15.
Nanomedicine (Lond) ; 2(1): 11-21, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17716187

RESUMO

Nanocarriers, such as nanoparticles, liposomes and dendrimers, are used to enhance ocular drug delivery. Easily administered as eye drops, these systems provide a prolonged residence time at the ocular surface after instillation, thus avoiding the clearance mechanisms of the eye. In combination with a controlled drug delivery, it should be possible to develop ocular formulations that provide therapeutic concentrations for a long period of time at the site of action, thereby reducing the dose administered as well as the instillation frequency. In intraocular drug delivery, the same systems can be used to protect and release the drug in a controlled way, reducing the number of injections required. Another potential advantage is the targeting of the drug to the site of action, leading to a decrease in the dose required and a decrease in side effects.


Assuntos
Portadores de Fármacos/química , Composição de Medicamentos/métodos , Oftalmopatias/tratamento farmacológico , Nanomedicina/métodos , Nanopartículas/química , Preparações Farmacêuticas/administração & dosagem , Veículos Farmacêuticos/química , Animais , Humanos , Nanopartículas/ultraestrutura , Tamanho da Partícula , Preparações Farmacêuticas/química
16.
Int J Pharm ; 337(1-2): 291-8, 2007 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-17300887

RESUMO

The cytotoxicity and physical properties of various submicron O/W emulsions and solid lipid nanoparticles for dermal applications were investigated. Droplet size and zetapotential of submicron emulsions depended on the composition of the cosurfactant blend used. The viability of J774 macrophages, mouse 3T3 fibroblasts and HaCaT keratinocytes was significantly reduced in the presence of stearylamine. Nanoparticles consisting of stearic acid or different kinds of adeps solidus could be manufactured when formulated with lecithin, sodium taurocholate, polysorbate 80 and stearylamine. Survival of macrophages was highly affected by stearic acid and stearylamine. In general a viability of more than 90% was observed when semi-synthetic glycerides or hard fat was employed to formulate nanoparticles.


Assuntos
Portadores de Fármacos , Emulsões , Lipídeos/toxicidade , Nanopartículas , Tensoativos/toxicidade , Administração Cutânea , Aminas/toxicidade , Animais , Células 3T3 BALB , Sobrevivência Celular/efeitos dos fármacos , Gorduras/toxicidade , Fibroblastos/efeitos dos fármacos , Humanos , Queratinócitos/efeitos dos fármacos , Lipídeos/administração & dosagem , Lipídeos/química , Macrófagos/efeitos dos fármacos , Camundongos , Tamanho da Partícula , Fosfatidilcolinas/toxicidade , Fosfatidilserinas/toxicidade , Polissorbatos/toxicidade , Óleo de Soja/toxicidade , Ácidos Esteáricos/toxicidade , Tensoativos/administração & dosagem , Tensoativos/química , Ácido Taurocólico/toxicidade , Água/química
18.
Int J Pharm ; 314(1): 72-82, 2006 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-16600538

RESUMO

The objective of present study was to prepare positively charged ciprofloxacin-loaded nanoparticles providing a controlled release formulation. The particles were prepared by water-in-oil-in-water (w/o/w) emulsification and solvent evaporation, followed by high-pressure homogenisation. Two non-biodegradable positively charged polymers, Eudragit RS100 and RL100, and the biodegradable polymer poly(lactic-co-glycolic acid) or PLGA were used alone or in combination, with varying ratios. The formulations were evaluated in terms of particle size and zeta potential. Differential scanning calorimetry measurements were carried out on the nanoparticles and on the pure polymers Eudragit and PLGA. Drug loading and release properties of the nanoparticles were examined. The antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus was determined. During solvent evaporation, the size and zeta potential of the nanoparticles did not change significantly. The mean diameter was dependent on the presence of Eudragit and on the viscosity of the organic phase. The zeta potential of all Eudragit containing nanoparticles was positive in ultrapure water (around +21/+25 mV). No burst effect but a prolonged drug release was observed from all formulations. The particles' activity against P. aeruginosa and S. aureus was comparable with an equally concentrated ciprofloxacin solution.


Assuntos
Resinas Acrílicas/química , Antibacterianos/química , Ciprofloxacina/química , Ácido Láctico/química , Ácido Poliglicólico/química , Polímeros/química , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Varredura Diferencial de Calorimetria , Química Farmacêutica , Ciprofloxacina/administração & dosagem , Ciprofloxacina/farmacologia , Preparações de Ação Retardada , Nanoestruturas , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Pseudomonas aeruginosa/efeitos dos fármacos , Solubilidade , Staphylococcus aureus/efeitos dos fármacos
19.
Eur J Pharm Biopharm ; 59(3): 527-36, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15760734

RESUMO

An experimental factorial design was employed to evaluate bioadhesive granules and bioerodible ocular minitablets (6 mg and Psi 2 mm). The purpose of this study was to compare minitablets prepared using roller compacted granules with an optimised minitablet formulation, manufactured on laboratory scale by direct compression. The formulation consisted of drum dried waxy maize starch, Carbopol 974P, and ciprofloxacin in a ratio of 90.5/5/3 (w/w/w). Three roller compactor parameters were varied, i.e. the roller speed, the horizontal screw speed and the compaction force, while the vertical screw speed was kept constant. Afterwards, the ribbons were milled to obtain granules suitable for compression. The friability, the flow properties, the bulk material characteristics (apparent and tap density and porosity) and the particle size distributions of two granule sieve fractions (90-125 and 125-355 microm) were investigated. The roller speed and the compaction force have the largest influence on the granule characteristics, followed by the horizontal screw speed. The physical properties of non- and gamma-irradiated minitablets were determined. From the tablet strength, friability and dissolution results, a low compaction force and a high roller speed were shown to be preferable to prepare granules which can be further tabletted into adequate ocular minitablets.


Assuntos
Tecnologia Farmacêutica/métodos , Adesivos Teciduais/síntese química , Olho/efeitos dos fármacos , Comprimidos , Tecnologia Farmacêutica/instrumentação , Adesivos Teciduais/administração & dosagem
20.
Chem Pharm Bull (Tokyo) ; 52(11): 1273-9, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15516745

RESUMO

Pilocarpine HCl-loaded PLGA nanoparticles were prepared by emulsification solvent evaporation. Three different stabilisers, polyvinylalcohol (PVA), Carbopol and Poloxamer were used, as well as mixtures thereof. The influence of the homogenisation pressure and number of cycles on the properties of nanoparticles were studied. Particle size was shown to depend on the stabiliser used. An increase of the homogenisation pressure or the number of cycles resulted in a decrease in particle size. The zeta potential value was influenced mainly by the nature of the stabiliser. Particles stabilised with poloxamer or PVA showed a slightly negative zeta potential value, while samples stabilised with carbopol possessed a more negative zeta potential, which became less negative after homogenisation. Drug encapsulation depended strongly on the stabiliser used. The higher drug entrapment of the carbopol-stabilised particles could be explained by an electrostatic interaction between the negatively charged carboxyl groups of carbopol and the positively charged, protonated pilocarpine. The drug release patterns of the particles prepared were quite similar. Differences between the release patterns of the homogenised particles could be attributed both to differences in size as well as drug encapsulation. Turbidimetric measurements suggested an interaction between mucin and PLGA nanoparticles exclusively stabilised with Carbopol.


Assuntos
Composição de Medicamentos/métodos , Ácido Láctico/química , Nanoestruturas/química , Ácido Poliglicólico/química , Polímeros/química , Fenômenos Químicos , Físico-Química , Ácido Láctico/farmacocinética , Tamanho da Partícula , Ácido Poliglicólico/farmacocinética , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros/farmacocinética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...