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Vitro Release (vitro + release)
Terms modified by Vitro Release Selected AbstractsUse of in vitro release of interferon-, in the diagnosis of contact allergy to potassium dichromate , a controlled studyCONTACT DERMATITIS, Issue 4 2003A. Trattner The use of in vitro release of interferon-, (IFN-,) in the diagnosis of contact allergy to potassium dichromate was studied in 20 patients who had positive patch tests to chromate and in 30 control subjects (10 patients with contact dermatitis, allergic to other allergens, 10 patients with other dermatologic diseases and 10 healthy subjects). The release of IFN-, in the supernatants of the peripheral blood lymphocytes was significantly higher in the patients with proven allergy to chromate (P = 0·001). Further studies are needed to determine if IFN-, release may serve as an additional diagnostic tool in contact dermatitis. [source] Long circulating nanoparticles of etoposide using PLGA-MPEG and PLGA-pluronic block copolymers: characterization, drug-release, blood-clearance, and biodistribution studiesDRUG DEVELOPMENT RESEARCH, Issue 4 2010Khushwant S. Yadav Abstract The anti-leukemic drug, etoposide (ETO), has variable oral bioavailability ranging from 24,74% with a short terminal half-life of 1.5,h i.v. necessitating continuous infusion for 24,34,h for the treatment of leukemia. In the present study, etoposide-loaded PLGA-based surface-modified nanoparticles (NPs) with long circulation were designed as an alternative to continuous i.v. administration. PLGA-mPEG and PLGA-PLURONIC copolymers were synthesised and used to prepared ETO-loaded NPs by high-pressure homogenization. The mean particle size of ETO-loaded PLGA-MPEG nanoparticles was 94.02±3.4,nm, with an Entrapment Efficiency (EE) of 71.2% and zeta potential value of ,6.9±1.3,mV. ETO-loaded PLGA-pluronic nanoparticles had a mean particle size of 148.0±2.1,nm, an EE of 73.12±2.7%, and zeta potential value of ,21.5±1.6,mV. In vitro release of the pure drug was complete within 4,h, but was sustained up to 7 days from PLGA-mPEG nanoparticles and for 5 days from PLGA-pluronic nanoparticles. Release was first order and followed non-Fickian diffusion kinetics in both instances. ETO and ETO-loaded PLGA nanoparticles labeled with 99mTc were used in blood clearance studies in rats where the two coated NPs, 99mTc- ETO-PLGA-PLU NP and 99mTc- ETO-PLGA-mPEG NP, were found to be available in higher concentrations in the circulation as compared to the pure drug. Biodistribution studies in mice showed that ETO-loaded PLGA-MPEG NP and PLGA-PLURONIC NP had reduced uptake by the RES due to their steric barrier properties and were present in the circulation for a longer time. Moreover, the NPs had greater uptake in bone and brain where concentration of the free drug, ETO, was negligible. Drug delivered from these NPs could result in a single i.v. injection that would release the drug for a number of days, which would be potentially beneficial and in better control of leukemia therapy. Drug Dev Res 71: 228,239, 2010. © 2010 Wiley-Liss, Inc. [source] Improving the dissolution and oral bioavailability of the poorly water-soluble drug aloe-emodin by solid dispersion with polyethylene glycol 6000DRUG DEVELOPMENT RESEARCH, Issue 5 2009Hao-gang Duan Abstract Solid dispersions (SDs) of aloe-emodin (AE) and polyethylene glycol 6000 (PEG6000) with different drug loadings were prepared, characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) and evaluated for solubility and in vitro release. The oral bioavailability of AE from SD in rats was compared with the crystalline drug. Plasma concentrations of AE were determined by HPLC. After administration of crystalline AE (35,mg·kg,1) in rats, the AUC0-600 and Cmax were 393.6±77.1,mg·min·l,1 and 1.87±0.30,mg·l,1, respectively. For the PEG6000 SD of AE, AUC0-600 and Cmax were boosted to 1310.5±111.9,mg·min·l,1 and 5.86±0.47,mg·l,1, respectively. The results indicated that the oral bioavailability of AE was increased significantly. Simultaneously, the Tmax value of AE for AE crystalline was decreased from 75.6±17.3,min to 44.8±14.8,min for SD. The earlier Tmax for AE from SD indicated the higher extent of absorption for SD due to their improved dissolution rate in rat intestine. This SD approach can therefore be used to enhanced dissolution and bioavailability for poorly water-soluble drugs. Drug Dev Res, 2009. © 2009 Wiley-Liss, Inc. [source] Simultaneous Immobilization of Bioactives During 3D Powder Printing of Bioceramic Drug-Release MatricesADVANCED FUNCTIONAL MATERIALS, Issue 10 2010Elke Vorndran Abstract The combination of a degradable bioceramic scaffold and a drug-delivery system in a single low temperature fabrication step is attractive for the reconstruction of bone defects. The production of calcium phosphate scaffolds by a multijet 3D printing system enables localized deposition of biologically active drugs and proteins with a spatial resolution of approximately 300,µm. In addition, homogeneous or localized polymer incorporation during printing with HPMC or chitosan hydrochloride allows the drug release kinetics to be retarded from first to zero order over a period of 3,4 days with release rates in the range 0.68%,0.96%,h,1. The reduction in biological activity of vancomycin, heparin, and rhBMP-2 following spraying through the ink jet nozzles is between 1% and 18%. For vancomycin, a further loss of biological activity following incorporation into a cement and subsequent in vitro release is 11%. While previously acknowledged as theoretically feasible, is its shown for the first time that bone grafts with simultaneous geometry, localized organic bioactive loading, and localized diffusion control are a physical reality. This breakthrough offers a new future for patients by providing the required material function to match patient bone health status, site of repair, and age. [source] Glucose-Responsive Bioinorganic Nanohybrid Membrane for Self-Regulated Insulin ReleaseADVANCED FUNCTIONAL MATERIALS, Issue 9 2010Claudia R. Gordijo Abstract A bioinorganic nanohybrid glucose-responsive membrane is developed for self-regulated insulin delivery analogous to a healthy human pancreas. The application of MnO2 nanoparticles as a multifunctional component in a glucose-responsive, protein-based membrane with embedded pH-responsive hydrogel nanoparticles is proposed. The bio-nanohybrid membrane is prepared by crosslinking bovine serum albumin (BSA),MnO2 nanoparticle conjugates with glucose oxidase and catalase in the presence of poly(N -isopropyl acrylamide- co -methacrylic acid) nanoparticles. The preparation and performance of this new nanocomposite material for a glucose-responsive insulin release system is presented. The activity and stability of immobilized glucose oxidase and the morphology and mechanical properties of the membrane are investigated. The enzymatic activity is well preserved in the membranes. The use of MnO2 nanoparticles not only reinforces the mechanical strength and the porous structure of the BSA-based membrane, but enhances the long-term stability of the enzymes. The in vitro release of insulin across the membrane is modulated by changes in glucose concentration mimicking possible fluctuations of blood-glucose level in diabetic patients. A four-fold increase in insulin permeation is observed when the glucose concentration is increased from normal to hyperglycemic levels, which returns to the baseline level when the glucose concentration is reduced to a normal level. [source] Preparation and stability of cosmetic formulations with an anti-aging peptideINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2008M.A. Ruiz Wrinkling of the skin is the most obvious sign of deterioration of the human body with age. This process involves a number of genetic, constitutional, hormonal, nutritional, and environmental factors, in addition to the influence of frequently repeated facial movements during laughing, smoking, etc. This article reviews the physiological basis and mechanism of action of the active cosmetic ingredient acetyl hexapeptide-8 (Argireline®). We prepared two formulations: an emulsion with an external aqueous phase for normal to dry skin, and a gel for oily skin. Laboratory analyses, rheology tests and in vitro release assays were used to evaluate the stability of these formulations for cosmetic treatment. [source] Preparation and in vitro release of D,L -tetrahydropalmatine-loaded graft copolymer nanoparticlesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Yinglei Zhai Abstract D,L -tetrahydropalmatine (THP)-loaded poly{[,-maleic anhydride-,-methoxy-poly(ethylene glycol)]- co -(ethy cyanoacrylate)} (PEGECA) amphiphilic graft copolymer nanoparticles (PEGECAT NPs) were prepared by the nanoprecipitation technique. The effects of solvent property, temperature, copolymer composition, and drug feeding on the drug-loaded amount and size of PEGECAT NPs were investigated. The morphological structure of PEGECAT NPs was characterized by transmission electron microscopy (TEM), proton nuclear magnetic resonance (1H NMR), and the size was measured by laser particle size analyzer (LPSA). In vitro release behaviors of drug from PEGECAT NPs were examined by high-pressure liquid chromatography (HPLC). The results demonstrate that PEGECAT NPs take on a spherical morphology with an inner core and outer shell before and after in vitro release. THP can be incorporated into the hydrophobic core of PEGECAT NPs and the drug-loaded amount is higher than 5%. The release of THP from PEGECAT NPs is initially fast and then slows down. The accumulated release is lower than 40% after 48 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis of pH dependent chitosan-EPI hydrogel films and their application for in vitro release of promethazine hydrochlorideJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Yolda Abstract Chitosan-epichlorohydrin hydrogel films (ChitEPI) were synthesized by using chitosan in the presence of epichlorohydrin (EPI) as a crosslinking agent at various amounts. SEM, FTIR, TGA, and DSC analysis were conducted for the characterization of the hydrogels. The DSC measurements indicate that ChitEPI hydrogels did not exhibit better thermal stability when compared to chitosan. Swelling behavior of Chitosan-EPI hydrogel film is pH dependent and showed a reversible swelling behavior with a fast response. The hydrogels were used for in vitro release of promethazine hydrochloride (PHCl) in pH = 1.2 and pH = 7.4 phosphate buffer solutions (PBS). The release of PHCl synthesized from hydrogels at pH = 7.4 is quite low while at pH = 1.2, the highest value was observed as 49% for ChitEPI600. It has been also found that PHCl release from ChitEPI thin films is mainly controlled by diffusion control mechanism. ChitEPI hydrogels may be used for the delivery of drug in stomach and gastrointestinal tract. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Microencapsulation of doxycycline into poly(lactide- co -glycolide) by spray drying technique: Effect of polymer molecular weight on process parametersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Pradip Patel Abstract Poly(lactide- co -glycolide) (PLGA) polymers with three different molecular weights were prepared, and microparticles were produced by spray drying and water-in-oil-water (w/o/w) double emulsion techniques to encapsulate 86% of doxycycline (DXY), an antibiotic drug, for the use of periodontitis. Placebo and drug-loaded microspheres and pristine DXY were analyzed by Fourier transform infrared spectroscopy, which indicated no chemical interactions between DXY and PLGA. X-ray diffraction of drug-loaded microspheres confirmed the molecular level dispersion of DXY in PLGA. Scanning electron microscopy confirmed spherical nature and smooth surfaces of the microspheres. Mean particle size as measured by laser light scattering technique ranged between 10 and 25 ,m. In vitro release of DXY performed in 7.4 pH media continued up to 72 h and depended on molecular weight of PLGA and extent of DXY loading. Antimicrobial studies performed on one formulation and placebo microspheres suggested that drug concentrations during in vitro release are above the minimum inhibitory concentration (MIC) for Staphylococcus aureus growth. Overall, the release studies depended on the molecular weight of PLGA, extent of drug loading, and the method used to prepare microspheres. Statistical analyses of release data performed using the analysis of variance (ANOVA) method agreed well with experimental observations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] In vitro release of complexed pDNA from biodegradable polymer filmsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Y. Ramgopal Abstract The controlled delivery of low-molecular weight drugs and proteins from biodegradable polymers has received considerable attention. However, controlled release studies of pDNA from such polymers have not been reported to date. In this study, a plasmid DNA was complexed with the cationic polymer called polyethylenimine (PEI). This gene vector has been shown to be very effective in transfecting cells. The complexed DNA were then incorporated into different types of poly-lactic- co -glycolic acid (PLGA) film; PLGA 53/47 (Mw 90 kDa), 50/50 (Mw 11 kDa, end group is lauryl ester) and 75/25 (Mw 120 kDa). Their release profiles from a buffer solution were studied. An initial (small) burst release of PEI-DNA from film was observed in PLGA 53/47 and 50/50, followed by a plateau phase and finally a rapid erosion-controlled release. For PLGA 50/50, the rapid release started after 14 days; erosion-controlled release for PLGA 53/47 started after 9 days; for PLGA 75/25, the release rate was governed by an initial burst release (10%) followed by a slow release controlled by diffusion. No obvious erosion-controlled release rate was observed for this polymer up to 27 days. Thus, the controlled release of complexed DNA follows the general features exhibited by lower- Mw drugs. This is of significance in designing gene vector matrices that offer the promise of more lasting gene therapy compared with particulate formulations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Swelling characteristics and drug delivery properties of nifedipine-loaded pH sensitive alginate,chitosan hydrogel beadsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Ya-Ni Dai Abstract The aim of the present work was to investigate the swelling behavior and in vitro release of nifedipine from alginate,chitosan hydrogel beads. Structure and surface morphology of the hydrogel were characterized by FTIR and SEM, respectively. Alginate,chitosan mixed beads and alginate,chitosan coated beads were prepared by ionic gelation method. The swelling ability of the beads and in vitro release of nifedipine in simulated gastric fluid (pH 1.5) and different phosphate buffer solutions (pH 2.5, 5.0, 6.8, 7.4, and 8.0) were found to be dependent on the presence of the polyelectrolyte complex between chitosan and alginate. The amount of nifedipine released from the mixed beads at pH 1.5 was relatively low (42%), whereas this value approached to 99% at pH 6.8. In comparison with the mixed beads, the released nifedipine from the coated beads was minimal at pH 1.5 (18%), whereas ,99% nifedipine was released at pH 6.8. The results suggested that the coated beads can hold drug better at low pH than the mixed beads and show excellent pH sensitivity. Therefore, the alginate,chitosan coated beads could be a suitable polymeric carrier for drug delivery in the intestinal tract. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Effects of Serotonin, GABA and Neuropeptide Y on Seabream Gonadotropin Releasing Hormone Release In Vitro from Preoptic-Anterior Hypothalamus and Pituitary of Red Seabream, Pagrus majorJOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2001B. Senthilkumaran Abstract The effects of serotonin (5-HT), GABA and neuropeptide Y (NPY) on in vitro release of seabream (sb) gonadotropin releasing hormone (GnRH) from slices of the preoptic-anterior hypothalamus (P-AH) and pituitary of red seabream were studied. 5-HT, GABA and NPY all stimulated the release of sbGnRH from the P-AH but not from the pituitary of immature red seabream. They also stimulated sbGnRH release from the P-AH with a similar potency during the course of gonadal development. Specific agonists and/or antagonists of 5-HT, GABA and NPY showed that 5-HT and GABA utilize 5-HT2 and GABAA receptor subtypes, respectively, to mediate their action, and that NPY employs at least NPYY1 and NPYY2 receptor subtypes to stimulate sbGnRH release. Combinations of different antagonists for 5-HT, GABA and noradrenaline/adrenaline did not block the stimulatory influence of NPY on release of sbGnRH, indicating that the action of NPY on the sbGnRH neuronal system is probably direct. [source] Evaluation of novel alginate foams as drug delivery systems in antimicrobial photodynamic therapy (aPDT) of infected wounds,An in vitro study: Studies on curcumin and curcuminoides XLJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2010Anne Bee Hegge Abstract The aim of the present study was to incorporate a model water-insoluble photosensitizer, curcumin, in novel alginate foams, further to evaluate the suitability of the curcumin loaded foams in antimicrobial photodynamic therapy of infected wounds. Six foam formulations were prepared and characterized with respect to physical characteristics, in vitro release and storage- and photo-stability of curcumin. One formulation was sterilized (,-sterilization). The foams contained hydroxypropyl-,-cyclodextrins or hydroxypropyl-,-cyclodextrins as solubilizers of curcumin. A reference foam without cyclodextrins was prepared with PEG 400 as the solubilizer. At a curcumin load of 0.153% (w/w), the water insoluble photosensitizer was uniformly distributed in the hydrophilic foams matrix. All foams were easy to handle, flexible and hydrated rapidly in a model physiological fluid. Release of curcumin in its monomeric form was demonstrated in vitro and found to be dependent on the type and amount of cyclodextrins in the formulation. Curcumin was stable during storage, but susceptible to photodegradation in the foams, especially when the formulations contain PEG 400 or hydroxypropyl-,-cyclodextrins. Curcumin did not degrade after ,-sterilization, however a decrease in the in vitro release rate of curcumin and changes in the foams physical characteristics were detected. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:3499,3513, 2010 [source] Preparation and evaluation of poly-butylcyanoacrylate nanoparticles for oral delivery of thymopentinJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2008Weiling He Abstract Thymopentin (Tp5) was loaded in poly-butylcyanoacrylate (PBCA) nanoparticles (NP) in order to enhance the oral bioavailability of Tp5. PBCA-Tp5-NP was prepared by nanoprecipitation methods. Dialyzing membrane method was employed to examine the in vitro release of PBCA-Tp5-NP in PBS, and Tp5 samples in the release medium were detected by HPLC. The cell proliferation test (3H-thymidine) was conducted to verify the PBCA-Tp5-NP bioactivity in vitro. The pharmacodynamical studies were performed on preimmunoinhibited rats and in flow cytometer. The size and the entrapment efficiency of PBCA-Tp5-NP were 178,±,39 nm and 92.21,±,1.08%, respectively. In vitro release data show that less than 60% Tp5 was released from lyophilized PBCA-Tp5-NP while 80% Tp5 was released from the colloidal PBCA-Tp5-NPs in 48 h. The proliferation test showed that PBCA-Tp5-NP had the similar effect as Tp5. The in vivo data showed that oral PBCA-Tp5-NPs had similar function as what intravenous Tp5 did. The oral bioavailability of Tp5 could be enhanced by PBCA nanoparticles. PBCA-Tp5-NP had the property of sustained-release and the efficacy of Tp5 was not changed after formulation. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:2249,2258, 2008 [source] Using a modified shepards method for optimization of a nanoparticulate cyclosporine a formulation prepared by a static mixer techniqueJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2008Dionysios Douroumis Abstract An innovative methodology has been used for the formulation development of Cyclosporine A (CyA) nanoparticles. In the present study the static mixer technique, which is a novel method for producing nanoparticles, was employed. The formulation optimum was calculated by the modified Shepard's method (MSM), an advanced data analysis technique not adopted so far in pharmaceutical applications. Controlled precipitation was achieved injecting the organic CyA solution rapidly into an aqueous protective solution by means of a static mixer. Furthermore the computer based MSM was implemented for data analysis, visualization, and application development. For the optimization studies, the gelatin/lipoid S75 amounts and the organic/aqueous phase were selected as independent variables while the obtained particle size as a dependent variable. The optimum predicted formulation was characterized by cryo-TEM microscopy, particle size measurements, stability, and in vitro release. The produced nanoparticles contain drug in amorphous state and decreased amounts of stabilizing agents. The dissolution rate of the lyophilized powder was significantly enhanced in the first 2 h. MSM was proved capable to interpret in detail and to predict with high accuracy the optimum formulation. The mixer technique was proved capable to develop CyA nanoparticulate formulations. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:919,930, 2008 [source] Solid-state solubility influences encapsulation and release of hydrophobic drugs from PLGA/PLA nanoparticlesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2004Jayanth Panyam Abstract Biodegradable nanoparticles formulated from poly(D,L -lactide- co -glycolide) (PLGA) and polylactide (PLA) polymers are being extensively investigated for various drug delivery applications. In this study, we hypothesize that the solid-state solubility of hydrophobic drugs in polymers could influence their encapsulation and release from nanoparticles. Dexamethasone and flutamide were used as model hydrophobic drugs. A simple, semiquantitative method based on drug,polymer phase separation was developed to determine the solid-state drug,polymer solubility. Nanoparticles using PLGA/PLA polymers were formulated using an emulsion,solvent evaporation technique, and were characterized for size, drug loading, and in vitro release. X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC) were used to determine the physical state of the encapsulated drug. Results demonstrated that the solid-state drug,polymer solubility depends on the polymer composition, molecular weight, and end-functional groups (ester or carboxyl) in polymer chains. Higher solid-state drug,polymer solubility resulted in higher drug encapsulation in nanoparticles, but followed an inverse correlation with the percent cumulative drug released. The XRD and DSC analyses demonstrated that the drug encapsulated in nanoparticles was present in the form of a molecular dispersion (dissolved state) in the polymer, whereas in microparticles, the drug was present in both molecular dispersion and crystalline forms. In conclusion, the solid-state drug,polymer solubility affects the nanoparticle characteristics, and thus could be used as an important preformulation parameter. © 2004 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 93:1804,1814, 2004 [source] Controlled drug release from gels using surfactant aggregates: I. Effect of lipophilic interactions for a series of uncharged substancesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2001Mattias Paulsson Abstract Gels are often used for the delivery of drugs because they have rheological properties that will give a long residence time. Most pharmaceutical gels consist of ,99% water and a polymer matrix that will not hinder the release of drugs with a small molecular weight. To fully take advantage of the residence time, it is necessary to have a sustained drug release. In this paper it is suggested that surfactant micelles can be used to control the release from gels. The in vitro release under physiological conditions of five parabens from four different poly(acrylic acid) gels (Carbopol 934, 940, 1342) and one gellan gum (Gelrite) gel was measured using a USP dissolution bath modified for gels, and the diffusion coefficients were calculated. The diffusion coefficient of uncharged parabens was generally lower in gels with lipophilic modifications, such as C1342, and the greatest effect was seen for butylparaben, with a diffusion that was 25% lower than that in C934 (lacking lipophilic modification). Addition of surfactant micelles to gels delayed the release of all the uncharged drugs in all types of gels studied. The slowest release was seen for butylparaben in a lipophilically modified gel with micelles present. The diffusion coefficient in such a system was almost 30 times smaller than that in C934 without micelles. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1216,1225, 2001 [source] Temperature-Triggered Nanosphere Formation Through Self-Assembly of Amphiphilic PolyphosphazeneMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 14 2006Jian Xiang Zhang Abstract Summary: An amphiphilic graft polyphosphazene with a molar ratio of poly(N -isopropylacrylamide) (PNIPAm) to ethyl glycinate (GlyEt) of 0.54:1 was synthesized. This copolymer in aqueous solution exhibited two temperature induced phase transitions at 17.2 and 33.7,°C, which correspond to the transformation of primary aggregate morphology (at Tph1) and the collapse of PNIPAm chains (at Tph2) respectively. Network micelles were assembled in water at lower temperature (far below Tph1), and then narrowly dispersed nanoparticles were formed above Tph1, while inter-nanoparticle aggregation occurred due to the collapse of PNIPAm chains surrounding the GlyEt core when the temperature was above Tph2. Through solubilization of the hydrophobic drug ibuprofen into polymeric aggregates at lower temperature, drug loaded nanospheres were prepared successfully. In vitro release revealed that sustained drug release was achieved with this novel delivery system. These results suggest that this novel copolymer could be used as a potential drug carrier, especially for the delivery of hydrophobic biocompounds through parenteral administration. Schematic illustration of the temperature-triggered self-assembly process of PNIPAm/GlyEt-PPP in aqueous solution. [source] Drug-specific in vitro release of IL-2, IL-5, IL-13 and IFN-, in patients with delayed-type drug hypersensitivityALLERGY, Issue 9 2009P. Lochmatter Background:, The most prevalent drug hypersensitivity reactions are T-cell mediated. The only established in vitro test for detecting T-cell sensitization to drugs is the lymphocyte transformation test, which is of limited practicability. To find an alternative in vitro method to detect drug-sensitized T cells, we screened the in vitro secretion of 17 cytokines/chemokines by peripheral blood mononuclear cells (PBMC) of patients with well-documented drug allergies, in order to identify the most promising cytokines/chemokines for detection of T-cell sensitization to drugs. Methods:, Peripheral blood mononuclear cell of 10 patients, five allergic to ,-lactams and five to sulfanilamides, and of five healthy controls were incubated for 3 days with the drug antigen. Cytokine concentrations were measured in the supernatants using commercially available 17-plex bead-based immunoassay kits. Results:, Among the 17 cytokines/chemokines analysed, interleukin-2 (IL-2), IL-5, IL-13 and interferon-, (IFN-,) secretion in response to the drugs were significantly increased in patients when compared with healthy controls. No difference in cytokine secretion patterns between sulfonamide- and ,-lactam-reactive PBMC could be observed. The secretion of other cytokines/chemokines showed a high variability among patients. Conclusion:, The measurement of IL-2, IL-5, IL-13 or IFN-, or a combination thereof might be a useful in vitro tool for detection of T-cell sensitization to drugs. Secretion of these cytokines seems independent of the type of drug antigen and the phenotype of the drug reaction. A study including a higher number of patients and controls will be needed to determine the exact sensitivity and specificity of this test. [source] Slow-release nanoparticle-encapsulated delivery system for laryngeal injection,THE LARYNGOSCOPE, Issue 5 2010Vasantha L. Kolachala PhD Abstract Objectives/Hypothesis: There is a need for a slow-release system for local delivery of therapeutics to the larynx. Most therapeutic substances, such as steroids or chemotherapeutic agents that are injected into the larynx are cleared rapidly. Repeated laryngeal injection of these substances at short intervals is impractical. Injectable encapsulated poly(lactide-co-glycolide) (PLGA) nanoparticles offer a potential slow-release delivery system for biologically active substances in the larynx. Study Design: Controlled animal study. Methods: PLGA nanoparticles were fabricated using a double emulsion method and were loaded with Texas Red-dextran (NPTR), hepatocyte growth factor (NPHGF), and bovine serum albumin (NPBSA). In vitro release of NPTR, NPBSA, and NPHGF was determined over approximately 2 weeks to assess potential duration of PLGA nanoparticle delivery. In vivo release of NPTR was assessed in a murine vocal fold injection model. The transcriptional effect of NPHGF on procollagen was measured in vitro to assess whether released growth factor retained functionality. Results: In vitro release kinetics demonstrated slow release of NPTR, NPBSA, and NPHGF over 12 to 14 days. In vitro NPTR release correlated with in vivo results. In vivo presence of NPTR occurred up to 7 days compared to 1 day for Texas Red control. In addition, NPHGF ameliorated transforming growth factor-, induced procollagen in vitro in 3T3 fibroblast cells. Conclusions: The results demonstrate the potential utility of nanoparticle encapsulation as an effective method for long-term delivery of specific drugs and biologically active substances to the larynx. Laryngoscope, 2010 [source] Three-dimensional fibrous PLGA/HAp composite scaffold for BMP-2 deliveryBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2008Hemin Nie Abstract A protein loaded three-dimensional scaffold can be used for protein delivery and bone tissue regeneration. The main objective of this project was to develop recombinant human bone morphogenetic protein-2 (rhBMP-2) loaded poly(D,L -lactide-co-glycolide)/hydroxylapatite (PLGA/HAp) composite fibrous scaffolds through a promising fabrication technique, electrospinning. In vitro release of BMP-2 from these scaffolds, and the attachment ability and viability of marrow derived messenchymal stem cells (MSCs) in the presence of the scaffolds were investigated. The PLGA/HAp composite scaffolds developed in this study exhibit good morphology and it was observed that HAp nanoparticles were homogeneously dispersed inside PLGA matrix within the scaffold. The composite scaffolds allowed sustained (2,8 weeks) release of BMP-2 whose release rate was accelerated with increasing HAp content. It was also shown that BMP-2 protein successfully maintained its integrity and natural conformations after undergoing the process of electrospinning. Cell culture experiments showed that the encapsulation of HAp could enhance cell attachment to scaffolds and lower cytotoxicity. Biotechnol. Bioeng. 2008;99: 223,234. © 2007 Wiley Periodicals, Inc. [source] | |||||||||||||