243 resultados para Thermodynamic formulation
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In this paper we describe the efficacy of the liposomal-AlClPc (aluminum-chloro-phthalocyanine) formulation in PDT study against Ehrlich tumor cells proliferation in immunocompetent swiss mice tongue. Experiments were conduced in sixteen tumor induced mice that were divided in three control groups: (1) tumor without treatment; (2) tumor with 100 J/cm(2) laser (670 nm) irradiation; and (3) tumor with AlClPc peritumoral injection; and a PDT experimental group when tumors received AlClPc injection followed by tumor irradiation. Control groups present similar macroscopically and histological patterns after treatments, while PDT treatment induced 90% of Ehrlich tumor necrosis after 24 h of one single showing the efficacy of liposome-AlClPc (aluminum-chloro-phthalocyanine) mediated PDT application, on the treatment of oral cancer. (C) 2008 Elsevier B.V. All rights reserved.
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In this study a magnetic nanoemulsion (MNE) was developed from a mixture of two components, namely biodegradable surfactants and biocompatible citrate-coated cobalt ferrite-based magnetic fluid, for entrapment of Zn(II)-Phthalocyanine (ZnPc), the latter a classical photosensitizer (PS) species used in photodynamic therapy (PDT) procedures. The sample`s stability was evaluated as a function of time using photocorrelation spectroscopy (PCS) for determination of the average hydrodynamic diameter, diameter dispersion and zeta potential. The ZnPc-loaded magneto nanoemulstion (ZnPc/MNE) formulation was evaluated in vitro assays to access the phototoxicity and the effect of application of AC magnetic fields (magnetohyperthermia damage) after incubation with J774-A1 macrophages cells. Darkness toxicity, phototoxicity and AC magnetic field exposures revealed an enhancement response for combined photodynamic and magnetohyperthermia (MHT) processes, indicating the presence of the synergic effect.
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Al-catechin/beta-cyclodextrin and Al-quercetin/beta-cyclodextrin (beta-CD) inclusion compounds were synthesized and characterized by IR, UV-vis, H-1 and C-13 NMR and TG and DTA analyses. Because quercetin is sparingly soluble in water, the stability constants of the Al-quercetin/beta-CD and Al-catechin/beta-CD compounds were determined by phase solubility studies. The A(L)-type diagrams indicated the formation of 1:1 inclusion compounds and allowed calculation of the stability constants. The thermodynamic parameters were obtained from the dependence of the stability constants on temperature and results indicated that the formation of the inclusion compounds is an enthalpically driven process. The thermal decomposition of the solid Al-quercetin/beta-CD and Al-catcchin/beta-CD inclusion compounds took place at different stages, compared with the respective precursors, proving that an inclusion complexation process really occurred. (C) 2007 Published by Elsevier B.V.
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Layered Double Hydroxides are a class of materials that can be described as positively charged layers of divalent and trivalent cations in the centre of edge-sharing octahedra. Cholesterol derivatives such as cholic acid are substances that play an important role in the digestion of fat components by the organism. This work presents a study on the intercalation of cholate anions in calcined MgAl-CO(3)-HDL. Isotherm experiments were performed at three different temperatures to evaluate the capacity of anion removal by sorption in the calcined LDH. The plateau was reached in all conditions. Increasing temperature results in decreasing cholate sorption. Characteristic peaks of LDH regenerated with OH(-) anions were observed at lower cholate concentrations. A peak in 2 theta equals to 7.5 degrees and peaks between 15 degrees and 20 degrees are observed. Those peaks are the same as the ones observed in the pure sodium cholate PXRD. At higher cholate concentrations the sorbed solids present PXRD related to an additional layered phase, which is related to intercalation of cholate anions with basal spacing equal to 34.3 angstrom. Thus, the cholate anions are also intercalated with a bilayer molecular arrangement at equilibrium concentrations at the isotherms plateau. (C) 2009 Elsevier Ltd. All rights reserved.
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Lipid microspheres (LM) are excellent drug delivery or vaccines adjuvant systems and are relatively stable. The aim of this work is to develop and characterize a system that is able to encapsulate and present antigenic membrane proteins from Leishmania amazonensis. Membrane proteins are important for vaccine`s formulation because these proteins come in contact with the host cell first, triggering the cell mediated immune response. This is a useful tool to avoid or inactivate the parasite invasion. The LM are constituted by soybean oil (SO), dipalmitoylphosphatidilcholine (DPPC), cholesterol and solubilized protein extract (SPE). The particles formed presented an average diameter of 200 run, low polydispersion and good stability for a period of 30 days, according to dynamic light scattering assays. Isopycnic density gradient centrifugation of LM-protein showed that proteins and lipids floated in the sucrose gradient (5-50%w/v) suggesting that the LM-protein preparation was homogeneous and that the proteins are interacting with the system. The results show that 85% of SPE proteins were encapsulated in the LM. Studies of cellular viability of murine peritoneal macrophages show that our system does not present cytotoxic effect for the macrophages and still stimulates their NO production (which makes its application as a vaccine adjuvant possible). LM-protein loaded with antigenic membrane proteins from L. amazonensis seems to be a promising vaccine system for immunization against leishmaniasis. (C) 2009 Elsevier Inc. All rights reserved.
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UV-VIS-Spectrophotometric and spectrofluorimetric methods have been developed and validated allowing the quantification of chloroaluminum phthalocyanine (CIAIPc) in nanocarriers. In order to validate the methods, the linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and selectivity were examined according to USP 30 and ICH guidelines. Linearities range were found between 0.50-3.00 mu g.mL(-1) (Y=0.3829 X [CIAIPc, mu g.mL(-1)] + 0.0126; r=0.9992) for spectrophotometry, and 0.05-1.00 mu g.mL(-1) (Y=2.24 x 10(6) X [CIAIPc, mu g.L(-1)] + 9.74 x 10(4); r=0.9978) for spectrofluorimetry. In addition, ANOVA and Lack-of-fit tests demonstrated that the regression equations were statistically significant (p<0.05), and the resulting linear model is fully adequate for both analytical methods. The LOD values were 0.09 and 0.01 mu g.mL(-1), while the LOCI were 0.27 and 0.04 mu g.mL(-1) for spectrophotometric and spectrofluorimetric methods, respectively. Repeatability and intermediate precision for proposed methods showed relative standard deviation (RSD) between 0.58% to 4.80%. The percent recovery ranged from 98.9% to 102.7% for spectrophotometric analyses and from 94.2% to 101.2% for spectrofluorimetry. No interferences from common excipients were detected and both methods were considered specific. Therefore, the methods are accurate, precise, specific, and reproducible and hence can be applied for quantification of CIAIPc in nanoemulsions (NE) and nanocapsules (NC).
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Autologous bone marrow mononuclear cell (BMMC) transplantation has emerged as a potential therapeutic option for refractory angina patients. Previous studies have shown conflicting myocardium reperfusion results. The present study evaluated safety and efficacy of CellPraxis Refractory Angina Cell Therapy Protocol (ReACT). in which a specific BMMC formulation was administered as the sole therapy for these patients. The phase I/IIa noncontrolled, open label. clinical trial, involved eight patients with refractory angina and viable ischemic myocardium, without left ventricular dysfunction and who were not suitable for conventional myocardial revascularization. ReACT is a surgical procedure involving a single series of multiple injections (40-90 injections, 0.2 ml each) into ischemic areas of the left ventricle. Primary endpoints were Canadian Cardiovascular Society Angina Classification (CCSAC) improvement at 18 months follow-up and myocardium ischemic area reduction (assessed by scintigraphic analysis) at 12 months follow-up, in correlation with a specific BMMC formulation. Almost all patients presented progressive improvement in angina classification beginning 3 months (p = 0.008) postprocedure which was sustained at 18 months follow-up (p = 0.004), as well as objective myocardium ischemic area reduction at 12 months (decrease of 84.4%, p < 0.004). A positive correlation was found between monocyte concentration and CCSAC improvement (r = -0.759, p < 0.05). Improvement in CCSAC, followed by correlated reduction in scintigraphic myocardium ischemic area, strongly suggests neoangiogenesis as the main stem cell action mechanism. The significant correlation between number of monocytes and improvement strongly supports a cell-related effect of ReACT. ReACT appeared safe and effective.
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Background There are occupational risks inherent to the activities of professional hairdressers, which are not frequently studied, and therefore not considered in the formulation of health policies for this group. Aims To verify the prevalence of work-related musculoskeletal disorders (WRMDs) in hairdressers through symptom reports, to characterize the most frequently affected anatomical parts and to identify and analyse risk factors of WRMDs in hairdressing. Methods A cross-sectional epidemiological study of 220 hairdressers from beauty parlours in Sao Paulo (Brazil) was carried out. Each hairdresser completed a self-administered questionnaire which included information on socio-demographic characteristics, working conditions and health-related musculoskeletal system complaints. Ergonomic analyses were also performed in six parlours. Results The prevalence of WRMDs was 71%. Risk factors were associated with psychosocial factors and factors related to discomfort and work fatigue such as lack of acknowledgement of work and uncomfortable posture at work [odds ratio (OR) = 3.54; 95% confidence interval (CI) 1.51-8.30], not feeling comfortable with body/neck/shoulders while working (OR = 2.78; 95% CI 1.40-5.54) and having > 15 years of professional activity (OR = 3.04; 95% CI 1.17-7.91). Conclusion Occupational risk factors associated with the development of WRMDs in hairdressers are related to biomechanical, organizational and psychosocial work factors. The high prevalence of WRMDs found highlights the importance of disseminating recommendations for prevention of symptoms with regards to the provision of suitable furniture, equipment and work tools, environmental conditions, size of workplace, work organization and psychosocial work factors.
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Background: Risperidone (RSP) is a benzisoxazole antipsychotic agent used to treat schizophrenia and other psychiatric illnesses in adults and children (including those with autism). After oral administration, RSP is completely absorbed from the gastrointestinal tract and undergoes hydroxylation to yield 9-hydroxyrisperidone (9-OH-RSP), an active metabolite that has a pharmacologic profile and potency similar to RSP. Objectives: The aims of this study were to compare the relative bioavailability of a pharmaceutical-equivalent (test) formulation with a reference formulation of oral RSP 2 mg, both available commercially on the Brazilian pharmaceutical market, and to generate data regarding the oral bioavailability of the tested drug in healthy Brazilian volunteers. Methods: This single-dose, randomized-sequence, open-label, 2-period crossover study was conducted in healthy Brazilian volunteers from August to December 2008. Subjects were randomly assigned to receive the test formulation followed by the reference formulation or vice versa, with a 30-day washout period between doses. Study drugs were administered after a 12-hour overnight fast. For pharmacokinetic analysis, blood samples were drawn at 0 (baseline), 0.25, 0.5, 1, 1.5, 3, 5, 8, 12, 24, 48, 72, 96, and 120 hours after administration. Plasma concentrations of RSP and 9-OH-RSP were determined using LC-MS/MS. The test and reference formulations were to be considered bioequivalent if the 90% CIs for the geometric mean test/reference ratios were within a predetermined range of 80% to 125%, in accordance with the policies of the Brazilian Sanitary Surveillance Agency and the US Food and Drug Administration. Tolerability was determined using clinical assessments, monitoring of vital signs, analysis of laboratory test results, and subject interviews regarding adverse events. Results: A total of 22 subjects were enrolled (11 men, 11 women; mean [SD] age, 32 [12] years [range, 18-58 years]; weight, 70.4 [11.9] kg [range, 50-103 kg]; height, 1.67 [0.08] m [range, 1.56-1.80 m]; and body mass index, 25 [4] kg/m(2) [range, 18-29 kg/m(2)]). For RSP, mean (SD) C(max) values were 12.6 (2.7) and 16.0 (2.3) ng/mL for the test and reference formulations, respectively. For 9-OH-RSP, mean C(max) values were 17.8 (1.3) and 21.0 (1.7) ng/mL for the test and reference formulations. The 90% CIs for the mean test/reference ratios for RSP C(max), AUC(0-120), and AUC(0-infinity) were 74% to 82%, 75% to 85%, and 76% to 85%, respectively, and 83% to 87%, 75% to 79%, and 75% to 78% for 9-OH-RSP. The related adverse events (headache, low back pain, drowsiness, standing hypotension, local postvenipuncture ecchymoses, insomnia, nausea, and vomiting) were transient and mild. Conclusions: This single-dose study found that the test and reference formulations of oral RSP 2 mg did not meet the Brazilian and US regulatory criteria for bioequivalence in these fasting, healthy volunteers. The study formulations appeared to be well tolerated. (Clin Ther 2010;32:2106-2115) (C) 2010 Elsevier HS Journals, Inc.
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Drug delivery systems are promising pharmaceutical formulations used to improve the therapeutic index of drugs. In this study, we developed a liposomal formulation of furazolidone that targets Leishmania (Leishmania) chagasi amastigotes in a hamster model. Using laser scanning confocal microscopy, it was demonstrated that the liposomal drug co-localised with L. (L.) chagasi amastigotes within macrophages. Liposomal furazolidone administered intraperitoneally at 0.5 mg/kg for 12 consecutive days reduced spleen (74%) and liver (32%) parasite burden at a 100-fold lower dose than the free drug. Free furazolidone (50 mg/kg) also effectively reduced spleen (82.5%) and liver (85%) parasites; its in vitro activity against promastigotes and intracellular amastigotes demonstrated a high degree of parasite selectivity. Thus, furazolidone, both in the free and liposome-loaded formulation, is an effective inhibitor of L. (L.) chagasi, representing a possible cost-effective drug candidate for the treatment of visceral leishmaniasis. (C) 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
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To evaluate the effects of heat acclimation on sweat rate redistribution and thermodynamic parameters, 9 tropical native volunteers were submitted to 11 days of exercise-heat exposures (40 +/- 0 degrees C and 45.1 +/- 0.2% relative humidity). Sudomotor function was evaluated by measuring total and local (forehead, chest, arm, forearm, and thigh) sweat rates, local sweat sodium concentration, and mean skin and rectal temperatures. We also calculated heat production (H), heat storage (S), heat exchange by radiation (R) and by convection (C), evaporated sweat (E(sw)), sweating efficiency (eta(sw)), skin wettedness (w(sk)), and the ratio between the heat storage and the sum of heat production and heat gains by radiation and convection (S/(H+R+C)). The heat acclimation increased the whole-body sweat rate and reduced the mean skin temperature. There were changes in the local sweat rate patterns: on the arm, forearm, and thigh it increased significantly from day 1 to day 11 (all p<0.05) and the sweat rates from the forehead and the chest showed a small nonsignificant increase (p=0.34 and 0.17, respectively). The relative increase of local sweat rates on day 11 was not different among the sites; however, when comparing the limbs (arm, forearm, and thigh) with the trunk (forehead and chest), there was a significant higher increase in the limbs (32 +/- 5%) in comparison to the trunk (11 +/- 2%, p=0.001). After the heat acclimation period we observed higher w(sk) and E(sw) and reduced S/(H+R+C), meaning greater thermoregulatory efficiency. The increase in the limb sweat rate, but not the increase in the trunk sweat rate, correlated with the increased w(sk), E(sw), and reduced S/(H+R+C) (p<0.05 to all). Altogether, it can be concluded that heat acclimation increased the limbs` sweat rates in tropical natives and that this increase led to increased loss of heat through evaporation of sweat and this higher sweat evaporation was related to higher thermoregulatory efficiency. J Physiol Anthropol 29(1): 1-12, 2010 http://www.jstage.jst.go.jp/browse/jpa2 [DOI: 10.2114/jpa2.29.1]
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In this study, the photodynamic action of liposomes (LP) and nanocapsules (NC) containing Chloroaluminum phthalocyanine (CIAIPc), on the human melanoma cell (WM 1552C), was assessed. The light source was setup at 672 nm, which corresponds to the maximum absorption wavelength of the CIAIPc. Both colloidal carriers presented size in nanometric scale as well as negative zeta potential. The cellular damage was light dose dependent ranging from 30% of cell death at 70 mJ.cm(-2) to 90% of death at 700 mJ.cm(-2). However, the photocytotoxic effect of LP at 70 mJ.cm(-2) was slightly more efficient to induce cellular death than NC formulation. At 140 mJ.cm(-2), and 700 mJ.cm(-2) both nanocarriers were equally efficient to induce cellular damage. Therefore, in the present work, the maximum phototoxic effect was obtained with 700 mJ.cm(-2) of light dose, in combination with 0.29 mu g.mL(-1) of CIAIPc encapsulated into LP and NC. The cells were also positive to annexin V, after the PDT treatment with LP and NC, showing that one of the mechanisms of cellular death involved is apoptosis. In summary, the potential of LP and NC as a drug delivery system, in Photodynamic Therapy (PDT) against melanoma, has been confirmed using a lower concentration of the photosensitizer and lower light doses than that applied in current protocols. This is an innovative proposal to treat melanoma cell lines that until now have not received the benefit of the PDT protocol for treatment.
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Introduction: Zinc is an essential element for human homeostasis being clearly related to almost all metabolic pathways. It is found in some neural circuitries, probably acting as a modulator of glutamatergic excitatory synapsis. In the auditory system its presence has been demonstrated within the cochlea and cochlear nuclei. Tinnitus symptoms are correlated to zinc physiology, and it has been postulated that the oligoelement could be used as an alternative treatment for this clinical situation. Aim: This study has evaluated the brainstem responses (ABR) in patients who suffer from chronic idiophatic tinnitus, before and after being treated with zinc. Neural transmissions in the brainstem auditory structures were also compared in both conditions. Materials and Methods: Forty-one patients (22 with tinnitus and 19 controls, groups I and II, respectively) were included in the study and submitted to anamnesis, otorhinolaryngologic examinations, biochemical evaluation and audiological tests. Group I patients received an specific zinc formulation for 90 days. ABR tests were performed at the beginning of the study and at the end of the zinc treatment. Results: First ABR tests showed no differences between the groups, but on the second evaluation there was a significant prolongation of the wave V latency and an enlargement of wave V amplitude shown in group I. Conclusion: Treatment with systemic zinc could change some aspects of auditory neurotransmission in the brainstem.
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Directed evolution techniques have been used to improve the thermal stability of the xylanase A from Bacillus subtilis (XylA). Two generations of random mutant libraries generated by error prone PCR coupled with a single generation of DNA shuffling produced a series of mutant proteins with increasing thermostability. The most Thermostable XylA variant from the third generation contained four mutations Q7H, G13R, S22P, and S179C that showed an increase in melting temperature of 20 degrees C. The thermodynamic properties Of a representative subset of nine XylA variants showing a range of thermostabilities were measured by thermal denaturation as monitored by the change in the far ultraviolet circular dichroism signal. Analysis of the data from these thermostable variants demonstrated a correlation between the decrease in the heat capacity change (Delta C(p)) with an increase in the midpoint of the transition temperature (T(m)) on transition from the native to the unfolded state. This result could not be interpreted within the context of the changes in accessible surface area of the protein on transition from the native to unfolded states. Since all the mutations are located at the surface of the protein, these results suggest that an explanation of the decrease in Delta C(p) on should include effects arising from the prot inlsolvent interface.
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The present study investigated the potential use of topical formulations containing marigold extract (ME) (Calendula officinalis extract) against ultraviolet (UV) B irradiation-induced skin damage. The physical and functional stabilities, as well as the skin penetration capacity, of the different topical formulations developed were evaluated. In addition, the in vivo capacity to prevent/treat the UVB irradiation-induced skin damage, in hairless mice, of the formulation with better skin penetration capacity was investigated. All of the formulations were physically and functionally stable. The gel formulation [Formulation 3 (F3)] was the most effective for the topical delivery of ME, which was detected as 0.21 mu g/cm(2) of narcissin and as 0.07 mu g/cm(2) of the rutin in the viable epidermis. This formulation was able to maintain glutathione reduced levels close to those of nonirradiated animals, but did not affect the gelatinase-9 and myeloperoxidase activities increased by exposure to UVB irradiation. In addition, F3 reduced the histological skin changes induced by UVB irradiation that appear as modifications of collagen fibrils. Therefore, the photoprotective effect in hairless mice achieved with the topical application of ME in gel formulation is most likely associated with a possible improvement in the collagen synthesis in the subepidermal connective tissue. (C) 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:2182-2193, 2011