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PubMed1993

Thermotropic behavior of phosphatidylcholine-glucosyl ceramide mixtures: effects of phospholipid acyl chain composition and interaction with water.

The thermotropic behavior of multilamellar vesicles composed of mixtures of dimyristoyl phosphatidylcholine-glucosyl ceramide and of egg phosphatidylcholine-glucosyl ceramide was investigated using differential scanning calorimetry. Macroscopic demixing of the lipid components occurred when multilamellar vesicles were prepared from mixtures of glucosyl ceramide and egg phosphatidylcholine by conventional methods. This problem was overcome by a technique based on spray drying of the lipid mixture. The results obtained for the two systems are compared with data available for dipalmitoyl phosphatidylcholine-glucosyl ceramide mixtures (Biochemistry 22 (1983) 3497-3501). All three phosphatidylcholines perturb the complex thermotropic behavior of glucosyl ceramide. The data suggest that the interference with intermolecular interactions among glycosyl ceramide molecules by phospholipid molecules is related to the molecular miscibility of the two components. This is strongly dependent on the acyl chain composition of the phosphatidylcholine and the water activity of the ambient aqueous phase.

Calorimetry, Differential Scanning↗
PubMed1996

Effects of traditional herbal medicine on gastric mucin against ethanol-induced gastric injury in rats.

The effect of the traditional herbal medicine, Rikkunshi-to and its component crude drugs, Zingiberis Rhizoma and Glycyrrhizae Radix, on the gastric mucin was studied using a method developed to separate and quantify the mucin localized in the different layers of rat gastric mucosa. The oral administration of spray-dried extract to Rikkunshi-to (1000 mg/kg), Zingiberis Rhizoma (500 mg/kg) and Glycyrrhizae Radix (500 mg/kg) significantly prevented gastric mucosal damage induced by 70% ethanol in rats. In ethanol-treated rats the mucin content of the deep mucosa was reduced, and the reduction of the deep corpus mucin content was significantly inhibited by pretreatment of Rikkunshi-to and Zingiberis Rhizoma. Rikkunshi-to and Glycyrrhizae Radix pretreatment increased the surface mucin content by 140 and 146%, respectively. The effect on the gastric mucin by each drug differed in the different layers of the gastric mucosa.

Administration, Oral↗
PubMedDate not supplied

Inhibitory effect of a mixture of herbal drugs (TJ-960, SK) on pentylenetetrazol-induced convulsions in E1 mice.

TJ-960 is a spray-dried mixture of 9 herbal drugs. The convulsions of E1 mice induced by pentylenetetrazol (18 mg/kg) were completely inhibited by p.o. administration of TJ-960 at a daily dose of 1.0 g/kg both in 8-week-old and 4-week-old E1 mice. These findings suggest that TJ-960 has an inhibitory effect on the convulsions of this hereditary animal model of epilepsy.

Animals↗
PubMed2005

Biodegradable mucoadhesive particulates for nasal and pulmonary antigen and DNA delivery.

Biodegradable polymer and particulate carriers have been shown to be of considerable potential for the delivery of peptides, proteins and DNA in animal models. In the context of vaccine delivery to the upper and lower respiratory tracts, the use of mucoadhesive agents offers a strategy for the facilitation of increased residence time and increased vaccine efficacy. Additional concerns addressed here include the potential of uptake of vaccine formulations by the primary olfactory nerves in the nasal cavity, effective delivery to the lung, strategies to maximise the immunopotentiation of candidate vaccine formulations, as well as the evaluation of animal models and interpretation of engendered immune responses in terms of antigen-specific antibody production. Experimental data are presented that demonstrate the potential of muco- and bioadhesive agents in combination with liposomes for intranasal (i.n.) delivery of tetanus toxoid in mice. A delivery system utilising chitosan for the formulation of microspheres by the spray-drying method is described and assessed for intranasal vaccine delivery, and porous particles with potential for pulmonary administration are also outlined.

Administration, Intranasal↗
PubMed2004

Functionalisation of allergen-loaded microspheres with wheat germ agglutinin for targeting enterocytes.

In this study, we constructed particles applicable for oral immunotherapy of type I allergy by protecting allergens from digestion and supporting intestinal antigen uptake. Therefore, birch-pollen allergens were entrapped in poly(d,l-lactic-co-glycolic acid) microspheres by spray-drying rendering microspheres with a main population of 1-3microm. Microspheres were further coated with wheat germ agglutinin (WGA) to target enterocytes. Coating with WGA did not alter the surface characteristics of the microspheres as demonstrated in scanning electron microscopy. Binding of WGA was specific and could be inhibited by chitotriose to 14.7+/-6.9%. Comparable amounts of allergen were released from both particle-types with 46.3+/-1.7% and 44.5+/-2.6% during 21 days. Simulating gastric digestion in vitro, antigenicity of allergens entrapped in WGA-microspheres was preserved to 59.8+/-1.5% even after 2h. Feedings of BALB/c mice with WGA-microspheres induced higher levels of allergen-specific IgG-levels than gavages of uncoated microparticles or naked protein. Thus, we conclude that WGA-microspheres are suitable vehicles for oral delivery and mucosal targeting due to lectin-mediated bioadhesion.

Allergens↗
PubMed2004

Preparation and physicochemical properties of compression-molded keratin films.

The S-sulfo keratin was extracted from wool and was then spray-dried to give S-sulfo keratin powder. Differential scanning calorimetry analysis showed that the glass transition temperature of S-sulfo keratins became lowered with the increase of moisture content, while perfectly dried S-sulfo keratin powder did not give thermal transition in the temperature range 30-130 degrees C. The compression molding of the S-sulfo keratin powder supplemented with one-tenth weight of water afforded a plastic-like transparent proteinous film above the glass transition temperature. The film obtained from the powder without water addition or compression molded below glass transition temperature partly remained powdery. The film compression molded at 120 degrees C gave the maximum ultimate strength and Young's modulus, 27.8 +/- 2.9 and 1218 +/- 80 MPa, respectively. Obtained film was insoluble and slightly swelled in water, but, in the presence of reducing agent, the film significantly swelled at pH 7.0 and even dissolved at pH 9.0, suggesting the relevance of abundant disulfide linkage. The film supported the mammalian cell adhesion and proliferation, demonstrating the biocompatibility of S-sulfo keratin films.

Animals↗
PubMed2004

Novel approach to fabricate keratin sponge scaffolds with controlled pore size and porosity.

A compression-molding/particulate-leaching (CM/PL) method was developed to fabricate S-sulfo keratin sponges with the controlled pore size and porosity. The S-sulfo keratin was extracted from wool and was then spray-dried to give S-sulfo keratin powder. The S-sulfo keratin powder mixed with urea in advance was compression-molded together with the sieved NaCl particulates above the melting temperature of urea. The following removal of the salts and urea in water created the sponges composed of interconnected pores and the continuous S-sulfo keratin matrix. The S-sulfo keratin sponges were strong enough to handle and water-insoluble. By contrast, the sponges prepared without urea were very fragile and readily collapsed, because most of S-sulfo keratin matrix remained powdery. The pore size was in good accordance with the size of the salts, indicating that the pores were formed by leaching-out the salts. The S-sulfo keratin sponges with the regulated sizes of pores (<100, 100-300 and 300-500 microm) were fabricated, all of which had more than 90% of the porosity. Thus, CM/PL method is able to give the S-sulfo keratin sponge with the desired pore size and porosity, which might be a good scaffold for the cells in tissue engineering.

Biocompatible Materials↗
PubMed2004

Bone-like apatite layer formation on hydroxyapatite prepared by spark plasma sintering (SPS).

Hydroxyapatite (HA) compacts with high density and superior mechanical properties were fabricated by spark plasma sintering (SPS) using spray-dried HA powders as feedstock. The formation of bone-like apatite layer on SPS consolidated HA compacts were investigated by soaking the HA compacts in simulated body fluid (SBF) for various periods (maximum of 28 days). The structural changes in HA post-SBF were analyzed with scanning electron microscopy, grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy. It was found that a layer consisting microcrystalline carbonate-containing hydroxyapatite was formed on the surface of HA compacts after soaking for 24h. The formation mechanism of apatite on the surface of HA compacts after soaking in SBF was attributed to the ion exchange between HA compacts and the SBF solution. The increase in ionic concentration of calcium and phosphorus as well as the increase in pH after SBF immersion resulted in an increase in ionic activity product of apatite in the solution, and provided a specific surface with a low interface energy that is conducive to the nucleation of apatite on the surface of HA compacts.

Apatites↗
PubMed2005

In vitro study of anticancer drug doxorubicin in PLGA-based microparticles.

Doxorubicin (DOX), also known as adriamycin, is an anthracycline drug commonly used in cancer chemotherapy. Unfortunately, its therapeutic potential has been restricted by its dose limited cardiotoxicity and the resistance developed by the tumor cells to the molecule after some time of treatment. One way to overcome these problems is to encapsulate the drug in poly (D, L-lactide-co-glycolide) (PLGA) microparticles. This paper investigates the release characteristics of DOX from polymeric carriers fabricated using the spray-drying technique. The encapsulation efficiency, size and morphology of the various polymeric devices were also determined. In order to improve the release characteristics, Pluronic P105 (PLU) and poly (L-Lactide) (PLLA) are individually used in combination with PLGA. Finally, a cytotoxicity test was performed using Glioma C6 cancer cells to investigate the cytotoxicity of DOX delivered from PLGA microparticles. It has been found that the cytotoxicity of DOX to Glioma C6 cancer cells is enhanced when DOX is delivered from PLGA polymeric carrier.

Animals↗
PubMed2006

Controlled release of gentamicin from calcium phosphate-poly(lactic acid-co-glycolic acid) composite bone cement.

Modification of a self setting bone cement with biodegradable microspheres to achieve controlled local release of antibiotics without compromising mechanical properties was investigated. Different biodegradable microsphere batches were prepared from poly(lactic-co-glycolic acid) (PLGA) using a spray-drying technique to encapsulate gentamicin crobefate varying PLGA composition and drug loading. Microsphere properties such as surface morphology, particle size and antibiotic drug release profiles were characterized. Microspheres were mixed with an apatitic calcium phosphate bone cement to generate an antibiotic drug delivery system for treatment of bone defects. All batches of cement/microsphere composites showed an unchanged compressive strength of 60 MPa and no increase in setting time. Antibiotic release increased with increasing drug loading of the microspheres up to 30% (w/w). Drug burst of gentamicin crobefate in the microspheres was abolished in cement/microsphere composites yielding nearly zero order release profiles. Modification of calcium phosphate cements using biodegradable microspheres proved to be an efficient drug delivery system allowing a broad range of 10-30% drug loading with uncompromised mechanical properties.

Animals↗
PubMed2006

The short-term effects on restenosis and thrombosis of echinomycin-eluting stents topcoated with a hydrophobic heparin-containing polymer.

Although drug-eluting stents (DESs) have become the most effective means of treating coronary artery disease, safety concerns regarding their thrombogenicities remain to be surmounted. Here, we report on a novel type of DES capable of preventing restenosis and thrombosis. The DES was prepared by coating a bare metal stent with echinomycin (an anti-proliferative drug) in polyurethane by a spray drying method. Hydrophobic heparinized polymer was then topcoated onto stent over echinomycin/PU layer by dipping to improve hemocompatibility. The two-layered stent was characterized regarding surface and cross-sectional morphology, drug release pattern, platelet adhesion in vitro, and restenosis in vivo. It was found that the heparin topcoat acts as a diffusion barrier that allows the controlled release of drug in a sustained manner. Also, the heparin coated layer effectively reduced platelet adhesion, indicating excellent hemocompatibility. From the animal test using pigs, it was evident that the developed DESs can minimize neointimal proliferation and thrombus formation. The devised hydrophobic heparinized polymer-coated DES effectively reduced both restenosis and thrombosis, suggesting that they have potential as tools for the treatment of coronary artery diseases.

Animals↗
PubMed2004

Synthesis, (1-->3)-beta-D-glucanase-binding ability, and phytoalexin-elicitor activity of a mixture of 3,4-epoxybutyl (1-->3)-beta-D-oligoglucosides.

We describe a approach for the synthesis of a mixture of 3,4-epoxybutyl (1-->3)-beta-D-oligoglucosides. The particular (1-->3)-beta-D-glucan isolated from the cell walls of Saccharomyces cerevisiae was recovered from the aqueous medium as water-insoluble particles by the spray drying (GS) method, and it was characterized by FTIR spectroscopy. The acid-solubilized (1-->3)-beta-D-oligoglucosides were prepared by partial acid hydrolysis of glucan particles, which were qualitatively analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE). The peracetylated 3-butenyl (1-->3)-beta-D-oligoglucosides were synthesized by treating peracetylated (1-->3)-beta-D-oligoglucosides with the 3-butenyl alcohols and a Lewis acid (SnCl4) catalyst. Epoxidation of the peracetylated 3-butenyl oligoglucosides took place with m-chloroperoxybenzoic acid (m-CPBA). NaOMe in dry methanol was used for the deacetylation of the blocked derivatives, to give the 3,4-epoxybutyl (1-->3)-beta-D-oligoglucoside mixture in an overall yield of 21%. The sample was analyzed by positive-ion electrospray ionization mass spectrometry (ESIMS). In a 3,4-epoxybutyl (1-->3)-beta-D-oligoglucoside-binding (1-->3)-beta-D-glucanase assay, we found that the (1-->3)-beta-D-glucanase was obviously inactivated by the 3,4-epoxybutyl (1-->3)-beta-D-oligoglucosides. At the same time, we found the 3,4-epoxybutyl (1-->3)-beta-D-oligoglucoside mixture was more active as compared to the underivatized oligoglucoside mixture in eliciting phytoalexin accumulation in tobacco cotyledon tissue. Furthermore, it could be kept for a longer time than a (1-->3)-beta-D-oligoglucoside mixture, which indicated it is much more stable than (1-->3)-beta-D-oligoglucosides.

Biological Assay↗
PubMed2005

Inclusion complexes of alpha- and gamma-cyclodextrins and the herbicide norflurazon: I. Preparation and characterisation. II. Enhanced solubilisation and removal from soils.

The interaction of norflurazon with alpha- and gamma-cyclodextrins (CDs) yielded the formation of inclusion complexes at a 1:1 stoichiometric ratio in solution and in the solid state. Apparent stability constants of 50.7+/-1.6 and 37+/-1.7 M(-1) and an increase in herbicide solubility by up to five and fourfold for alpha- and gamma-CD, respectively, were determined from the phase solubility diagrams at 25 degrees C in water. Three processing methods (kneading, spray-drying and vacuum evaporation) were used to prepare norflurazon-CD solid inclusion complexes, which were characterised by infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy. A high increase in the norflurazon dissolution rate was obtained with all the solid complexes with gamma-CD, but when alpha-CD was used, only the solid system obtained after the vacuum evaporation process showed a higher dissolution rate. This finding is a first step in the development of new, environmentally sound formulations of norflurazon (NFL), due to the capacity for increasing its dissolution rate and hydrosolubility, and thus diminishing the use of organic solvents. On the other hand, the effect of alpha- and gamma-cyclodextrin on the solubility of norflurazon in solution was also considered as a way of modifying its behaviour in the soil environment. Desorption studies of NFL from soils in the presence of alpha- and gamma-cyclodextrin were carried out using a batch equilibration method. The results obtained showed that alpha- and gamma-cyclodextrin greatly increased the removal of norflurazon previously adsorbed, proving the potential use of these CDs for in situ remediation of pesticide-contaminated soils.

Adsorption↗
PubMed2004

Thermally-treated clay as a stationary phase in liquid chromatography.

Spray-dried, spherical synthetic hectorite particles have been thermally-treated at 500 degrees C for 16 h and used as adsorbent materials in reversed-phase liquid chromatography. The retention of a 22 mono and disubstituted aromatic compounds was evaluated to study the retention mechanisms on the clay mineral. The retention of solutes on the thermally-treated clays was markedly different than that measured on octadecylsilica (ODS) columns under identical conditions, but remarkably similar to retention characteristics of the same solutes on porous graphitic carbon columns. The clay columns exhibit an enhanced selectivity over the ODS column in separation of nitroaromatic positional isomers. Under identical mobile phase compositions, a selectivity, alpha, of 7.15 between ortho- and para-dinitrobenzene isomers was measured on the clay column compared to a alpha of 1.04 on the ODS column.

Adsorption↗
PubMed2006

Surface composition of dairy powders observed by X-ray photoelectron spectroscopy and effects on their rehydration properties.

The surface composition of three dairy powders was investigated by X-ray photoelectron spectroscopy. These spray-dried casein powders were more or less enriched in hygroscopic material (lactose and/or minerals). The principal limitation of these high protein content powders is their poor rehydration ability. Consequently, information about surface composition is required in order to get a better understanding of rehydration behaviour (i.e. wetting time and time of rehydration). The obtained results indicate that the surface of the three powders was dominated by proteins. Lactose and minerals are marginal compounds at the surface whereas the surface coverage of fat was over represented. A correlation between the lactose surface content and the wetting time of the powders was found, but no relationship with the surface fat. Moreover, as the surface is partly depleted in minerals and lactose, it is concluded that these compounds are principally located in the bulk of the particle. Therefore this observation could be related with a wetting time of the powders only slightly affected by the addition of hygroscopic material whereas the time of rehydration was strongly improved; powder wetting being more affected by the surface composition whereas powder dispersion being more influenced by the powder bulk composition.

Caseins↗
PubMed2004

Single-step granulation/tabletting of different grades of lactose: a comparison with high shear granulation and compression.

The influence of the particle size, particle morphology and crystallinity of lactose on the extrusion properties and on the quality of tablets were investigated using single-step granulation/tabletting as a tabletting technique. Results showed that particle size and type of lactose (alpha-lactose monohydrate, anhydrous beta-lactose and spray dried lactose) affected the powder feeding, the process performance as well as the process capacity. Different grades of lactose yielded tablets with similar tensile strength, but significantly different disintegration time. Single-step granulation/tabletting always yielded tablets with a significantly higher tensile strength and similar or significantly lower disintegration time compared to high shear granulation and compression. The tensile strength of alpha-lactose monohydrate tablets (without and with PVP) did not change during one year of storage at 60% RH-25 degrees C and at 75% RH-40 degrees C, whereas a significant increase in disintegration time was observed. It can be concluded that although the lactose grade affected the performance and the optimal parameters of single-step granulation/tabletting, all lactose grades can be efficiently processed using this technique.

Compressive Strength↗
PubMed2004

Transfection of a mouse dendritic cell line by plasmid DNA-loaded PLGA microparticles in vitro.

Targeting of DC for DNA vaccination may be achieved by DNA-loaded poly(lactide-co-glycolide) (PLGA) biodegradable microparticles, since DC efficiently capture these microparticles in vitro and in vivo. DNA was encapsulated in PLGA microparticles by spray-drying. Various additives were tested and process parameters adjusted in order to prevent degradation of the DNA during encapsulation. The highest degree of supercoiled DNA was maintained by adding a strong buffering agent, such as PBS or NaHCO(3), whereas the cryoprotective lactose did not show a significant protective effect. DNA-containing PLGA microparticles were administered to a mouse DC line. Transfection efficacy was compared with commonly employed cationic transfectants and was visually assessed by green fluorescent protein expression. Transfection rate was very low in DC for all microparticle formulations and was comparable with commonly used cationic transfectants. It is concluded that the transfection of DC using PLGA microparticles is feasible, but efforts need to be undertaken to improve transfection efficiency in vitro, which may in addition lead to improved immune responses in vivo.

Animals↗
PubMed2005

Chitosan and poly(methyl vinyl ether-co-maleic anhydride) microparticles as nasal sustained delivery systems.

An original dosage form for nasal delivery based on the encapsulation of hydrophilic drug in chitosan-poly(methyl vinyl ether-co-maleic anhydride) (CH-PVM/MA) microparticles prepared by spray-drying technique was developed. Microparticles were characterized in terms of morphology, size, swelling properties, encapsulation efficiency and drug release. The physical state of the drug and the polymer was determined by scanning electron microscopy (SEM) and infrared spectroscopy (IR). Propranolol hydrochloride (PH) was a beta-blocker, used for the treatment of hypertension and was chosen as a model of hydrophilic drug. SEM studies showed spherical particles with smooth surfaces for chitosan hydrochloride (CH-HCl), whereas rather gross surface defects resulted from the incorporation of poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA). In vitro release studies revealed a sustained release of propranolol HCl from microparticles and in particular chitosan hydrochloride provided the lowest release of drug.

Adhesiveness↗