Showing papers on "Gelatin published in 1991"

Visceral surgery patch

Abstract: A patch for visceral surgery is made from a biomaterial consisting of two layers of collagen superimposed and closely combined, namely a porous adhesive layer of fibrous collagen and a film of collagen and/or gelatin.

Poly(hydroxybutyrate-hydroxyvalerate) microspheres containing progesterone: preparation, morphology and release properties.

Abstract: The biodegradable polyesters, poly(hydroxybutyrate) (PHB) and poly(hydroxybutyrate-hydroxyvalerate) (PHBV) were investigated for use as sustained delivery carriers of a model drug, progesterone. Spherical microspheres containing the drug were prepared by an emulsion solvent-evaporation method with gelatin as an emulsifier. Methylene chloride as the polymer solvent yielded smoother microspheres than chloroform. The surface texture was also dependent upon the temperature of the preparation and polymer used. Surface crystals were observed when the drug loading was increased beyond 5 per cent w/w. Thermograms of the microspheres did not show an endotherm corresponding to the melting of the drug because the drug dissolved in the melted polymer while heating. The amount of residual solvent in the microspheres (gas chromatographic assay) ranged from 3-4 to 58-4 ppm and was dependent on the processing temperature, concentration of the polymer in the solvent and the polymer composition. In vitro release of...

Method for making a capsule-shaped tablet

Abstract: A method for making a multi-characteristic, bi-layer, capsule-shaped tablet by filling a die with a blend of one or more excipients and one or more active substances, including a first distinguishing ingredient, e.g., a first coloring agent, leveling the first blend and cleaning the die walls above the first blend, adding a second blend including a second distinguishing ingredient, e.g., a second coloring agent, and compressing both blends longitudinally in the die into the shape of a two component capsule. The tablet is coated with a clear coating, such as gelatin, to provide a solid medicament with the appearance of a gelatin capsule.

Formation of microemulsion-based gelatin gels

Abstract: Gelatin-containing water-in-oil microemulsions are known to form clear gels under appropriate conditions of temperatures and polymer concentrations. The sol-gel transition involves aggregation of the nanometer-sized gelatin-filled aqueous droplets and cross-linking due to intermolecular tropocollagen-like helix formation of the polypeptide

Structure and stability of microemulsion-based organo-gels

Abstract: The phase stability, structure and physical (mechanical) properties of gelatin-containing, AOT-stabilised microemulsion-based organo-gels have been studied as a function of their composition. Phase-stability studies indicate that the presence of small amounts of gelatin changes the shape and extent of the single-phase microemulsion region with respect to temperature. Small-angle neutron scattering shows that the gel structure is based on coexisting gelatin–water networks and microemulsion droplets. The gel structure is sensitive to the AOT and gelatin concentrations, water content, added salts and the nature of the oil used as the continuous phase. The likelihood of gel formation is linked to the proximity of the microemulsion upper-temperature phase boundary and the gelatin helix–coil transition temperature at ca. 32 °C. The frequency dependence of the elastic moduli of the organo-gels is similar to that of aqueous gelatin gels, being characteristic of a viscoelastic solid. The network strand density, derived from the relaxed elastic modulus, is consistent with the same parameter calculated from neutron scattering measurements.

Incipient behaviour of gelatin gels

Abstract: The present work describes isothermal (25°C) gelation measurements for gelatin gels over a range of concentrations. Methods for the estimation of the gel time are discussed, and data compared with two recent models. The isothermal time growth of modulus is also investigated, and the superposition of such data discussed. For concentrations close to the critical gel concentration C 0 there are significant deviations in the latter case. These may be related to the approach to the biphasic region of the phase diagram suggested by other workers.

Capsule-shaped tablet

Abstract: A multi-characteristic, bi-layer, capsule-shaped tablet consists of a blend or one or more excipients, one or more active substances, and may consist of a first and second different coloring agent compressed longitudinally into the shape of a two color capsule. The multi-colored tablet is coated with a clear coating, such as gelatin, to provide a solid medicament with the appearance of a gelatin capsule.

Palatal pressure patterns of gelatin gels in the mouth

Abstract: Palatal pressures of gelatin gel at various concentrations were detected by pressure transducers set at three locations in the palate. The following parameters were derived from the palatal pressure patterns: P, mean of palatal pressure from the beginning of eating to the end of swallowing; S, the last pulse of swallowing; T, retaining time of the sample in the mouth and W, energy consumed in the course of time until swallowing. P and W increased as the gelatin concentration increased from 1.0–4.0% and then they decreased as the gelatin concentrations exceeded 4.0%. T increased linearly over the whole range of gelatin concentrations. Changes in gelatin concentration had little effect on S. It was concluded that oral action changed primarily from crushing by the tongue against the palate to biting by the teeth as the toughness of the gelatin gel increased.

Odorless cosmetic compositions in gelatin capsules

Abstract: A cosmetic product is disclosed in the form of a gelatin walled capsule encompassing a cosmetic composition that includes a carrier which is a silicone polymer and an antioxidant The antioxidant operates to inhibit degradation of the gelatin wall to prevent malodors from being generated Retinoic acid derivatives such as retinyl palmitate are especially effective as antioxidants

High amylose starch substituted gelatin capsules.

Abstract: A gelatin capsule sheath in which a portion of the gelatin is replaced with a high amylose content starch to provide a dry capsule sheath having 3-60% by weight high amylose starch wherein the amylose content of the starch is at least 50% and preferably 90% high amylose starch. The capsules of this invention have textured frosted or satin finish which do not stick together, form strong seals, are resistant to changes in shape, and are more economical to manufacture.

Silver Halide (Sensitized) Gelatin in Agfa-Gevaert Plates: The Optimized Procedure

Abstract: Silver halide sensitized gelatin (SHSG) is one of the most promising techniques for the fabrication of transmission holographic optical elements, achieving relatively high sensitivity of photographic material with the low scattering and high light stability of dichromated gelatin. In this paper we present the optimized procedure in Agfa-Gevaert plates. Diffraction gratings with a diffraction efficiency up to 80% and a noise level of less than 1% are obtained with a sensitivity 103 times better than dichromated gelatin.

Rheological properties of protein/starch mixed gels

Abstract: The influence on the viscoelastic behaviour of the heat transition temperatures of starch and protein in gelatinous systems prepared from the two components was studied. Four different starches were combined with Bovine Serum Albumin (BSA) in several protein-to-starch ratios. Both the transition temperature and the rates of gelation of the components were critical for the behaviour of the complex systems. In those cases where the starch gel was formed before the protein gel, the storage and loss moduli of the complex system could be predicted by a simple addition of the moduli of the components at corresponding concentrations. When the gelation occurred in the reverse order, the gels were considerably stronger than predicted by the additivity model. When the starches were combined with gelatin, the complex gels were all weaker than predicted. The gelation of gelatin was very slow compared to that of the starches and the BSA, and it is likely that the weakness of these gels was due to the aggregation of the amylose molecules or some other part of the starch retrogradation process.

Acid–base surface properties of modified poly(ethylene terephthalate) films and gelatin: Relationship to adhesion

Abstract: Characterization of poly(ethylene terephthalate) (PET) films surfaces through wettability measurements and inverse gas chromatography techniques leads to a better knowledge of the potential interactions with a coating. An important case is the one relative to gelatin coatings for photographic films. In order to favor adhesion on PET, it is of interest to examine the problem in terms of acid–base interactions. PET is found amphoteric and gelatin rather basic. Several surface treatments on PET like orientation on water and flame or plasma treatment in air lead to an increase in surface acidity. Adhesion with gelatin as determined by the peel test is increased through a flame treatment, because of the higher acidity of PET and subsequent chemical bonding at the interface. Determination of acid-base surface properties of PET and gelatin appears to be an excellent tool for adhesion prediction.

Mixed-walled microcapsules made of cross-linked proteins and polysaccharides: Preparation and properties

Abstract: Microcapsules were prepared through an interfacial cross-linking process using terephthaloylchloride and applied to mixtures of a protein (human serum albumin or gelatin) and a polysaccharide. Their properties were compared with those of microcapsules prepared from the protein alone. Morphological characteristics of mixed-walled microcapsules were often modified, as seen by light and electron microscopy. Otherwise, they appeared to be more resistant to digestive media: they were gastroresistant, and their degradation time in pancreatin was prolonged upon raising the amount of polysaccharide. Moreover, the lysis time was shown to depend on the nature of the polysaccharide: microcapsules prepared from acidic polysaccharides at pH 9.8 were hydrolyzed faster. Lastly, the resistance increased upon decreasing the polymers/acylchloride ratio, or upon raising the reaction pH. Encapsulation assays were carried out with sodium salicylate, which was incorporated with a high efficiency. Mixed-walled microcapsules allowed a prolonged release of the tracer in vitro. As compared with protein microcapsules, the release profiles of batches prepared with hydroxyethylstarch exhibited only slight modifications of the initial part of the curve, while a significant burst effect was observed with carboxymethylcellulose-containing microcapsules.

Tests for detecting degradation of gelatin: comparison of five methods.

Abstract: Five methods for detecting degradation of gelatin by bacteria were compared. These were liquefaction in nutrient broth, hydrolysis in nutrient agar, hydrolysis of charcoal gelatin strips, degradation of the gelatin on strips of photographic film, and alkalinization of gelatin agar. Degradation of photographic film is a rapid and convenient method but, like hydrolysis of gelatin in broth and in agar, may fail to detect weakly positive strains of bacteria. Alkalinization of gelatin in an agar medium is a convenient and sensitive method to detect degradation of gelatin, particularly by Pseudomonas fluorescens, but this method may not be applicable to some species.

Control of pressure-fog with gelatin-grafted and case-hardened gelatin-grafted soft polymer latex particles

Abstract: This invention describes a substantially less pressure sensitive photographic film comprising a support, at least one light sensitive silver halide element, and an overlaying element comprising gelatin-grafted or case-hardened gelatin-grafted soft polymer particle composite element. The incorporation of such an overlaying composite particle cushioning layer does not compromise either the physical properties or physical integrity of the film unit. This invention is particularly suitable for highly pressure sensitive tabular grain emulsions.

A novel metalloproteinase present in freshly isolated rat glomeruli.

Abstract: We have utilized [3H] gelatin to document high activity of a metalloproteinase present in freshly isolated rat glomeruli. [3H] gelatin degradation by glomeruli was markedly inhibited by EDTA (10 mM: -89 +/- 2.3%) and o-phenanthroline (2 mM: -72 +/- 0.1%), inhibitors of metalloproteinases. No significant inhibition of [3H]gelatin degradation was observed with inhibitors of serine or cysteine proteinases. Most (greater than 80%) of the glomerular metalloproteinase (GLOMP) activity was associated with the pellet after centrifugation of sonicated glomeruli at 100,000 g for 90 min. The pH optimum for gelatin degradation by sonicated glomeruli was approximately pH 8.5. Sodium dodecyl sulfate substrate (gelatin)-polyacrylamide gel electrophoresis revealed a single major band of EDTA-inhibitable gelatin-degrading activity with a molecular mass of approximately 116-125 kDa. The GLOMP activity was not inhibited by tissue inhibitors of metalloproteinases, did not appear to be latent, and was not activated by organomercurial activators of several latent metalloproteinases. GLOMP activity was increased 3.4-fold after incubation with trypsin (20 micrograms/ml, 25 min, 22 degrees C). These data indicate that GLOMP is distinct from the previously described matrix metalloproteinases, as well as other metalloproteinases present in the kidney, including the gelatinase secreted by cultured mesangial cells, Meprin, and endopeptidase 24.11 (enkephalinase, EC 3.4.24.11).

The effect of the cross-linking time period upon the drug release and the dynamic swelling of gelatin microspheres.

Abstract: The cross-linking time period affected both the swelling and release processes of cross-linked gelatin microspheres. In the dynamic swelling procedure, the combination of both phenomena of microparticle swelling and drug diffusion produced at first the increase and then the decrease of the diameter of a loaded microsphere. The increase of the cross-linking time period produced the shift of the penetrant transport from anomalous to super-case II kinetics. This behaviour could justify the decrease of the diffusion component of the drug release as the cross-linking time period increased.

A biologically derived medical adhesive and its uses

Abstract: An adhesive composition suited for surgical applications which consists essentially of an aqueous solution of natural collagen or gelatin which has a melt index temperature within the range of 35 °C to 45 °C.

Regulation of hydroxyapatite formation by gelatin and type I collagen gels.

Abstract: Calcium and phosphate were allowed to diffuse into gelatin and Type I collagen gels which were then cut into slices and analyzed for ion concentrations. Solutions of calcium and phosphate were then prepared, with ion concentrations equivalent to the highest levels in the slices, and mixed together, whereupon a rapid and copious precipitation of hydroxyapatite (HA) was observed. In contrast, HA bands were not visible in the gels until 1 to 21/2 days after analysis. These results indicate that Type I collagen exerts a considerable inhibitory effect on HA proliferation, probably by steric blockage of nuclei and crystal formation and growth. It thus appears that Type I collagen should be added to the list of agents that perform a regulatory role in bone mineral formation.

Element having adhesion of gelatin and emulsion coatings to polyester film

Abstract: A polymeric film substrate is first modified, then coated with a polyalkyl acrylate/gelatin layer to improve the wet adhesion of the layer to the substrate The layer may itself contain a photographic emulsion or emulsion layers may be adhered to that layer

Crosslinked latex blends based on gelatin : synthesis, morphology, thermal, and mechanical properties

Abstract: By the synthesis of crosslinked latex blend from gelatin and methyl methacrylate (MMA) and n-butylacrylate (n-BA) copolymers, the thermal stability of gelatin is improved. Gelatin is made compatible with MMA-co-n-BA by crosslinking. The brittle film of gelatin in made flexible and the tensile strength analysis shows fully crosslinked blend has better tensile strength, when compared to partially cross-linked blends

Synthesis of protein-coated gelatin microspheres and their use as microcarriers for cell culture. Part I. Derivatization with native collagen.

Abstract: A novel technique for the synthesis of native collagen (type I)-coated gelatin microspheres was developed using the emulsion-polymerization principle, which is realized in four steps: emulsification, separation, stabilization, and protein modification A 20% gelatin solution was emulsified in sunflower oil and the resulting beads were polymerized with glutaraldehyde The novelty of our technique consists in the protein modification step, where we derivatized the beads by saturation of the free aldehyde groups on the cross-linked gelatin in the native collagen solution (03 mg/ml in 005 M Tris, pH 86) and further stabilized the beads with sodium borohydride The resulting microspheres exhibited excellent properties as microcarriers for in vitro cell culturing using Vero cells as the model system In comparison with pure gelatin beads, the cells attached more rapidly and grew faster on native collagen-coated beads Approximately 90% of the Vero cells attached to the microcarrier after 1 h After a lag per

Method for casting dissolvable ophthalmic shields in a mold

Abstract: A method for making a biosoluble collagen or gelatin ophthalmic shield, which optionally contains a pharmaceutically active agent, by casting collagen or gelatin in a mold; chilling the mold with the collagen or gelatin shield until the shield is strong enough to allow the mold to be opened without deforming the shield in one half of the mold; drying the collagen or gelatin shield while it is still in the mold; and then cross-linking the collagen or gelatin shield to achieve the desired solubility. The resulting shield can be worn comfortably in the eye and leaves no observable material after complete dissolution and drug release.