Showing papers on "Gelatin published in 1992"

Effect of pH and salt on the adsorption and interactions of an amphoteric polyelectrolyte

Abstract: Adsorption and surface force measurements were carried out on gelatin (MW∼100 000) adsorbed on mica from aqueous NaCl solutions. Measurements were made over a range of ionic strengths and pH. The results show that gelatin adsorbs via discrete ionic bonds formed between negative surface groups on mica and positive basic groups on gelatin; these exist even when gelatin is net negatively charged (at a pH above the IEP of 5.0). The phenomenon of strong adsorption even when both the polymer and surface are net negatively charged does not appear to occur with macromolecules containing only acidic groups

Microencapsulated oil field chemicals

Abstract: Gelatin capsules containing oil field chemicals, preferably weighted with a heavy metal compound, are made more stable under certain conditions by the incorporation of a strong chelating agent. The microcapsules can provide an extended treatment period since many materials that would damage the microcapsules are controlled by the chelating agent.

The Effect of Sucrose on the Thermo-Reversible Gel-Sol Transition in Agarose and Gelatin

Abstract: The effects of sucrose on the elasticity and thermoreversible gel-sol transition in agarose and gelatin gels were studied. The concentration and temperature dependence of the elastic modulus was analysed by current theories of gel elasticity. The gel-sol transition observed by differential scanning calorimetry was discussed or the basis of a zipper model approach. It was suggested that the number of junction zones increased, the size of each junction zone decreased, and the rotational freedom of a link in a zipper decreased by the addition of sucrose.

Biodegradable gelatin-aminodextran particle coatings of and processes for making same

Abstract: The invention relates generally to colloidal particle having a core material and a gelatin/aminodextran coating with pendent functional groups attached thereto. Biological substances or molecules, especially monoclonal antibodies, may be attached to said particles. The monoclonal antibody containing particles are useful in a variety of positive and negative biological assays.

Soft gelatin capsules

Abstract: In a dropping procedure for the formation of soft gelatin capsules in which, suitably, a pasty, fluid or sol/gel forming filling material is encapsulated with a soft gelatin mass, the solidification of the soft gelatin mass in a cooling bath of a chemically inert, exceedingly cold fluid which has no negative biological impact nor leaves harmful residue on the soft gelatin capsule. As cooling bath, there is most suitably utilized liquid nitrogen.

Sustained-release injection

Abstract: The present invention relates to a sustained-release injection, which comprises a suspension of a powder comprising an active ingredient and a pharmaceutically acceptable biodegradable carrier (e.g. proteins, polysaccharides and synthetic high molecular compounds, preferably collagen, atelocollagen, gelatin, and a mixture thereof) in a viscous solvent for injection (e.g. vegetable oils, polyethylene glycol, propylene glycol, silicone oil, and medium-chain fatty acid triglycerides). The sustained-release injection can release the active ingredient at an effective level for a long period of time when injected.

Pellets containing plant extracts, process of making same and their pharmaceutical peroral or cosmetic use

Abstract: Plant extract containing pellets are formed by a dispersion of plant extract or extracts in a matrix, principally comprising a skeleton builder namely collagen, gelatin, fractionated gelatin, a collagen hydrolysate, gelatin derivative plant proteins, or plant protein hydrolysates. They are shelf stable and their pharmacological as well as cosmetic properties are substantially unchanged in comparison to the native extracts. They may be produced by a simple process in which a solution of the skeleton former is mixed with liquid plant extract or emulsified with solid extracts, dissolved or suspended, the dispersion of the skeleton former and the plant extract dropped into a very cold inert fluid, suitably liquid nitrogen, to form the pellets and the thus formed pellets dried.

A collagen/gelatin-binding decapeptide derived from bovine propolypeptide of von Willebrand factor.

Abstract: Propolypeptide of von Willebrand factor (pp-vWF) binds to type I collagen, and we have reported that a binding domain exists in a 21.5/21-kDa fragment originated from the C-terminal portion [Takagi, J., Fujisawa, T., Sekiya, F., & Saito, Y. (1991) J. Biol. Chem. 266, 5575-5579]. The collagen-binding property of the 21.5/21-kDa fragment was compared with that of the intact pp-vWF. Although pp-v WF preferentially binds to native type I collagen fibrils, the isolated fragment no longer has this specificity and binds well to collagen of other types in the native and heat-denatured states. In order to determine the critical site that mediates this collagen/gelatin binding, several peptides were synthesized based on the primary structure of the 21.5/21-kDa fragment. Among these, a 25-residue peptide strongly inhibited the binding of the 125I-labeled 21.5/21-kDa fragment to collagen. Using this inhibitory effect as an index, the binding site was defined to the sequence as follows: WREPSFCALS. Furthermore, a decapeptide of this sequence bound to collagen and gelatin, indicating that this sequence is responsible for the binding of the 21.5/21-kDa fragment to collagen/gelatin.

Polyacrylate resin microcapsules for taste masking of antibiotics.

Abstract: Various microencapsulated dosage forms were prepared to limit the release of an antibiotic in solution for up to 3 days and in the oral cavity following per oral administration. An experimental antibiotic, clarithromycin (TE-031), was used in these studies. The drug was first encapsulated in gelatin followed in some cases by crosslinking with glutaraldehyde. The gelatin microcapsules were then coated with acrylic resins (Eudragit®), whose solubility properties vary according to pH. A non-solvent coacervation technique was used to apply the Eudragit resins. It was found that crosslinking the gelatin retarded release of TE-031 somewhat relative to that from uncrosslinked gelatin microcapsules in a 72 h release experiment conducted at room temperature. Coating the gelatin microcapsules with Eudragit resins L100, S100, or E100 slowed the release of TE-031 further still; less TE-031 was released over 72 h from the Eudragit-coated formulations prepared with crosslinked gelatin compared with formulations...

MR microscopy of chick embryo vasculature

Abstract: Six-day-old chick embryos were examined with magnetic resonance microscopy after vascular perfusion fixation and perfusion with gadolinium-doped gelatin to highlight the developing vascular anatomy. Gadolinium gelatin, with its short T1, provided a source of signal contrast within the vessels. The entire embryo was embedded in gelatin to minimize susceptibility artifacts that are prevalent at the high field strength (7.0 T) used. A series of single-section spin-echo images were acquired with various TRs to determine the optimal imaging sequence for a three-dimensional (3D) acquisition. The combination of gadolinium gelatin in the vascular spaces, gelatin embedding of the specimen, and optimal acquisition parameters yielded a 3D stack of high-resolution images that was readily reconstructed and rendered to effectively demonstrate the developing thoracic vessels in the embryo.

The interaction of anionic surfactants with gelatin

Abstract: The binding of sodium dodecyl sulfate and a hydrophilic color coupler anion to gelatin was investigated using a surfactant-selective electrode. The binding isotherms of the surfactants to an alkali-processed bone gelatin, as well as an acid-processed bone gelatin were determined and compared with viscosity data. The comparison shows that viscosity measurements can only be regarded as circumstantial evidence for binding. At nearly identical binding isotherms the viscosity curves were found to be very different.

Effect of water mobility on drug hydrolysis rates in gelatin gels.

Abstract: The stability of drugs incorporated in gelatin gels was studied, with a focus on the water mobility in the gels. Trichlormethiazide hydrolysis and kanamycin-catalyzed flomoxef hydrolysis in gelatin gels were chosen as models for apparent first-order and second-order hydrolysis, respectively. The mobility of water in gelatin gels was determined by NMR, ESR, and dielectric relaxation spectroscopies. The amount of bound water in the gels was determined from dielectric relaxation spectra. Spin-lattice relaxation time of water determined by 17O NMR and rotational correlation time of an ESR probe determined by an ESR probing method were useful in determining the micro viscosity of the gels. The hydrolysis rate of trichlormethi-azide in the gels was found to depend on the amount of free water available for the reaction, while that of flomoxef depended on the micro viscosity of the gels, which reflected the mobility of water molecules. Thus the dependence of hydrolysis rates on the water mobility was influenced by the hydrolysis mechanism.

Diagnostic and therapeutic compositions

Abstract: Compositions, such as liquid therapeutic or diagnostic compositions, and methods for their preparation and involving their use. The compositions comprise an effective amount of gelatin from cold water fish skin as a protein base. The indicated gelatin provides many significant advantages and improvements, including for instance its high stabilizing effect on labile organic substrates included in the compositions, and its low temperature gelling properties which provide improved compositions which do not substantially gel during refrigeration. Further representative advantages relate to its behavior as a zwitterion thus reducing or eliminating needs for buffers, and its surprising behavior similar to human serum protein in protein analyses such as the biuret procedure.

The Interactions Between Gelatin and Surfactants — A Rheological Study

Abstract: Gelatin and surfactants are ubiquitous in photographic products. Addition of surfactants to gelatin solutions may have little effect or may lead to dramatic changes in physical properties. Here, a rheological study of gelatin solutions in the presence and absence of surfactant is reported. Simple viscometry-shear rate data is supplemented by investigations of the complex rheology using oscillation, stress relaxation, stress growth and pulse shearometry. The effects of ionic (AOT, SDS and CTAB) surfactants and nonionic (alkyl polyether) surfactants on the rheology of gelatin solutions are compared. Anionic surfactants, at con-centrations above the CMC (in gelatin), lead to a greater increase in viscosity than do cationic surfactants. Nonionic surfactants have little effect on the viscosity of gelatin solutions. All solutions exhibit similar complex rheology. At low frequencies (w < 1000 s-1) the behaviour is dominated by the loss (viscous/liquid) rather than the storage elastic/solid) component. Th...

In vitro and in vivo digestion of collagen covalently immobilized onto the silicone surface.

Abstract: In order to study the in vivo digestion of immobilized collagen and gelatin, these proteins labeled with 125I or fluorescein isothiocyanate (FITC) were covalently immobilized onto silicone surfaces, which were grafted with acrylic acid to introduce carboxyl groups, and implanted subcutaneously in rats and mice. When the proteins were labeled with FITC, the amount of proteins immobilized decreased with the increase of the number of FITC molecules conjugated with the protein molecule. In the wet state, FITC conjugated with the proteins was less stable than 125I. Approximately half of the amount of the immobilized proteins was digested in vivo within the first week and until 5 weeks after implantation the proteins were gradually digested. At that time, the amount of the proteins remaining on the silicone surface ranged from 0.6 to 1.0 μg/cm2, which was several times larger than the amount of an assumed monolayer adsorption of proteins. Even after 15 weeks, the amount of proteins remaining on the silicone was almost the same as after 5 weeks. No significant difference in digestion was observed between collagen and gelatin, regardless of the labeling agent. Because of less stability and easier handling of FITC and higher stability and more difficult handling of 125I, FITC seems more suitable for short-term and 125I for long-term studies. © 1992 John Wiley & Sons, Inc.

Effects of Polyols and Sugars on the Sol-Gel Transition of Gelatin

Abstract: The melting temperature of gelatin gel increased with increasing concentrations of polyols and sugars added at any gelatin concentation. The enthalpy of gel melting measured by Eldridge-Ferry plots and calorimetric measurements was decreased by addition of these polyhydric compounds, indicating that the gel stabilization by them is predominantly due to the large decrease in entropy of gel melting. Circular dichroism analysis showed that the helix formation of gelatin molecules was enhanced with increasing concentrations of these additives, but there was no positive correlation between their helix-forming ability and gel-stabilizing ability. The viscosity of gelatin solution was less in these mixed solvents than in water. Based on these results, a possible stabilization mechanism of gelatin gel by polyhydric compounds was discussed, in comparison with that of native collagen, in terms of the thermodynamics of protein-solvent interactions.

A Comparison of Substrates for Human Umbilical Vein Endothelial Cell Culture

Abstract: We have studied culture conditions which facilitate the growth of stable, non-proliferating, human umbilical vein endothelial cell (HUVEC) monolayers. Gelatin and fibronectin coatings, with or without glutaraldehyde cross-linking, on both plastic and glass were investigated for initial attachment of HUVEC and growth characteristics. The presence during culture of intercellular (IC) junctions demonstrated by silver staining, expression of platelet endothelial cell adhesion molecule-1 (PECAM-1) and maintenance of a cobblestone appearance of HUVEC monolayers were assessed over time. Glutaraldehyde cross-linked fibronectin and gelatin coatings on glass and glutaraldehyde cross-linked gelatin or untreated fibronectin coatings on plastic served as good substrates for short term culture. Long term (20 days) cultures of HUVEC which maintained silver and PECAM-1 staining of IC junctions and a cobblestone appearance could be achieved if glutaraldehyde cross-linked gelatin coatings on glass were used as substrates.

Gelatin or collagen hydrolysate containing drug formulation that provides for immediate release of nanoparticle drug compounds

Abstract: Nanosols and process for preparing the same allow colloidally dispersed solutions of scarcely water-soluble active substances to be stabilized with gelatin or its derivatives, by partly or fully setting the iso-ionic point (IIP, equivalent to a neutral charge) between the gelatin and the surface charged active substance particles. In order to neutralize the charge of the system composed of active substance particles and gelatin, the surface charge of the particles is compensated by a corresponding opposite charge of the gelatin molecules. For that purpose, a determined charge in relation to the isoelectric point (IEP) and the pH value of the solution is set on the gelatin molecules. By stabilizing in this way the practically monodispersed state thus generated, the Ostwald maturation of the colloidal particles of scarcely soluble active substance is strongly reduced. A new form of pharmaceutical administration having new properties can thus be obtained with generally scarcely water-soluble inorganic and organic compounds, in particular medicaments with a problematic bioavailablity. Preferred medicaments are glibenclamide and 3-indolylacetic acid derivatives, such as indomethacin or acemetacin.

Properties of Agents that Effectively Entrap Liquid Lipids

Abstract: A droplet of an oil-in-water emulsion of methyl linoleate in a saccharide or protein solution that contained with a surfactant, a stabilizer, or both was dehydrated by drying equipment for a single droplet that resembled a spray drier. The lipid exposed on the surface of dehydated samples was extracted and measured by gas chromatography. Gum arabic or gelatin without additives resulted in little lipid being exposed; they were good entrapping agents. Little lipid was exposed with a pullulan solution containing lecithin, sugar ester, carboxymethylcellulose, or sodium caseinate but much was exposed with a maltodextrin solution containing any of the surfactants tested. When both the surfactant lecithin and the stabilizer xanthan gum were added to the emulsion prepared in a maltodextrin solution, lipid was not detected. The results suggested that effective entrapping agents of liquid lipids cause much emulsification, stabilize the emulsion (that is, they cause the continuous phase to be very viscous), and create a dehydrated matrix of fine, dense network layers.

Nonwoven fabric coated with a mixture of silk fibroin, gelatin and insolubilized chitosan for use as a carrier for animal cells

Abstract: A carrier for adhering animal cells during culturing or for immobilization of animal cells is produced by coating a porous substrate with a cell adhesive material in the form of a mixture with chitosan. In a preferred embodiment, the porous substrate is a nonwoven fabric prepared by impregnating a nonwoven fabric web with a binder resin, and the mixture contains silk fibroin, gelatin and chitosan. Coating is carried out by contacting the nonwoven fabric with a solution prepared by adding silk fibroin and gelatin to an acidic aqueous solution of chitosan to coat the nonwoven fabric, drying the coated nonwoven fabric and treating the dried nonwoven fabric with an alkali to render the chitosan insoluble.

Effect of gelatin properties in complex coacervation processes

Abstract: The effects of Bloom grade and iso-electric-point of gelatin on the complex coacervation with acacia and micro-encapsulation of theobromine were investigated. The zetapotential of various gelatins and acacia was measured at different pH values and compared with the optimal pH range for complex coacervation. Values for electrical equivalence pH of gelatins and acacia were in the same range as the maximal coacervate volumes. For the high Bloom grade gelatins the pH range in which most complex coacervate was formed was smaller for Alkaline-processed gelatin than for Acid-processed gelatins. The same small pH range was observed for the low Bloom grade gelatin of the Acid-type compared to high Bloom grade gelatins of the same type. The total amount of complex coacervate increased and the relative contents of theobromine in microcapsules decreased for gelatins with high Bloom grade. Microcapsules prepared with a high Bloom grade gelatin were irregular shaped and showed poor flow characteristics. No diff...