ABSTRACT
Oral administration of diluted solutions of insulin results in the absorption of the hormone into bloodstream. After oral administration of diluted insulin solutions to healthy volunteers and animals with experimental diabetes insulin does not undergo hydrolytic degradation under the action of proteolytic enzymes and its absorption is sufficient to produce the hypoglycemic effect. This approach gives a chance of creating of novel strategy for diabetes treatment.
Subject(s)
Blood Glucose/analysis , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/drug therapy , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Administration, Oral , Adult , Animals , Dose-Response Relationship, Drug , Female , Humans , Male , Middle Aged , Rabbits , Rats , Rats, WistarABSTRACT
Relatively short polymer chains with lower critical solution temperatures were immobilized on protein macromolecules to obtain biodegradable polymeric derivatives of proteins (including those for heat-inactivated targeting of polypeptide drugs). Addition of a derivative to a multicomponent biological system and heating of the target to a temperature in excess of the lower critical solution temperature was followed by the carrier release into a separate phase and the transportation of the bound protein to the target. The protein molecule served as a biodegradable region and was progressively hydrolyzed, with the formation of low-molecular-weight fragments. These fragments were readily eliminated from the organism. The physiological activity of immobilized serum albumin was independent of the number of attached chains in the polymer carrier (the constant of bilirubin binding equaled 10 M(-1)). The biodegradation of synthetic systems, caused by alpha-chymotrypsin, was also studied. The more polymer chains were attached to serum albumin, the greater was the resistance of the protein to enzymatic hydrolysis.
Subject(s)
Acrylamides/chemistry , Drug Carriers/chemistry , Peptides/chemistry , Pharmaceutical Preparations/chemistry , Polymers/chemistry , Bilirubin/chemistry , Biotransformation , Serum Albumin/chemistry , TemperatureABSTRACT
Experiments on animals showed that native proteins may diffuse into the blood flow after oral administration of diluted protein solutions. An in vitro study led us to hypothesize that treatment with diluted solutions is accompanied by a decrease in the rate of protein proteolysis and accelerated protein diffusion through the intestinal mucosa.
Subject(s)
Proteins/pharmacology , Administration, Oral , Animals , Chromatography , Diffusion , Electrolytes , Hydrolysis , Male , Proteins/administration & dosage , Proteins/chemistry , Rabbits , SolutionsABSTRACT
The influence of oral insulin upon carbohydrate exchange in healthy volunteers was evaluated. One of the two forms of insulin used in the study was insulin, immobilized in a volume of polyacrylamide gel, modified by ovomucoid (proteolytic enzyme inhibitor), isolated from duck eggs; the other form was enteric-coated tablets bases on hydrogel substance. The oral administration of the hydrogel substance or the tablets resulted in the fall of blood glucose concentration by 34.9 +/- 4.4% and 28.6 +/- 6.9%, respectively. The maximal effect of the hydrogel substance and the tablets was observed at the 90th and the 180th minutes.
Subject(s)
Diabetes Mellitus/drug therapy , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Administration, Oral , Adult , Blood Glucose/analysis , Carbohydrate Metabolism , Female , Humans , Hydrogel, Polyethylene Glycol Dimethacrylate , Hypoglycemic Agents/isolation & purification , Insulin/isolation & purification , Male , Middle Aged , Tablets , Time FactorsABSTRACT
The polyacrylamide hydrogels with covalently immobilized ovomucoid from the duck's egg white were synthesized by radical copolymerization. These hydrogels can defend the immobilized insulin against the action of proteolytic enzymes. Biospecific interaction of the polysaccharide component of ovomucoid with lectins leads to the targeting transport of the hydrogel particles onto the small intestine wall.
Subject(s)
Chromatography/methods , Acrylic Resins , Animals , Ducks , HydrogelsABSTRACT
Copolymers of N,N-diethylacrylamide and N-acryloylphthalimide with lower critical solution temperature (LCST) were synthesized by radical copolymerization. Polymeric systems with antithrombin activity and LCST were prepared via a reaction of amino groups of hirudin with phthalimide groups of the copolymers. On increasing hirudin content, LCST of the polymeric systems increased. The antithrombin activity of polymeric systems obtained by hirudin immobilization on copolymer carriers was inversely related to the content of the copolymer, amounting to 6% of the activity of native hirudin.
Subject(s)
Antithrombins/chemical synthesis , Drug Delivery Systems , Polymers/chemical synthesis , Temperature , Acrylamides/chemistry , Antithrombins/chemistry , Drug Carriers/chemical synthesis , Drug Carriers/chemistry , Hirudins/chemistry , Phthalimides/chemistry , Polymers/chemistryABSTRACT
A new approach to overcome the degradation of protein drugs by proteolytic enzymes and their targeting to the blood through the digestive apparatus was developed. The approach is based on the immobilization of drugs into the polymeric hydrogel containing glycoprotein--ovomucoid from duck egg whites. This glycoprotein inhibits the activity of proteolytic enzymes and acts as a biospecific ligand to lectins on the walls of the gastrointestinal tract.
Subject(s)
Drug Delivery Systems , Gastric Mucosa/pathology , Ovomucin/chemistry , Polymers/chemistry , Administration, Oral , Animals , Biocompatible Materials , Ducks , Egg White , Glucose/metabolism , Hydrogel, Polyethylene Glycol Dimethacrylate , Insulin/metabolism , Kinetics , Ligands , Polysaccharides/metabolism , Rabbits , Rats , Time Factors , WaterABSTRACT
The stability of polyacrylamide hydrogel, modified by ovomucoid with immobilized insulin was studied at different pH of external medium. At 3.8 < pH < 5.5 insulin binds to the gel, due to electrostatic interaction between ovomucoid and insulin molecules.
Subject(s)
Insulin/chemistry , Acrylic Resins/chemistry , Animals , Drug Carriers , Drug Stability , Ducks , Hydrogels , Hydrogen-Ion Concentration , Kinetics , Osmolar Concentration , Ovomucin/chemistryABSTRACT
A new approach to overcome the degradation of insulin by proteolytic enzymes and its targeting to the blood through the digestive apparatus was developed. The approach is based on the immobilization of insulin into the polymeric hydrogel which is modified by ovomucoid--glycoprotein, inhibitor of proteolytic enzymes. Oral administration of this system to rabbits and rats, (in contrast to the hydrogels modified by proteolytic enzymes inhibitors without polysaccharide part), statistically significantly lowered blood glucose level.
Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Ovomucin/administration & dosage , Trypsin Inhibitors/administration & dosage , Animals , Drug Carriers , Rabbits , RatsABSTRACT
A mathematical simulation is presented which describes the in vitro drug delivery kinetics from hydrophilic adhesive water-soluble poly-N-vinylpyrrolidone (PVP)-polyethylene glycol (PEG) matrices of transdermal therapeutic systems (TTS) across skin-imitating hydrophobic Carbosil membranes. Propranolol is employed as the test drug. The contributions of the following physicochemical determinants to drug delivery rate control have been estimated: the drug diffusion coefficients both in the matrix and the membrane; the membrane-matrix drug partition coefficient: the drug concentration in the matrix and the membrane thickness. Drug transfer from the hydrophilic matrix across the membrane is shown to be controlled by the drug partitioning from the matrix into the membrane. The best correlation between simulation data and experimental results is obtained when the effect of membrane hydration is taken into consideration during in vitro drug release.
Subject(s)
Administration, Cutaneous , Drug Delivery Systems/statistics & numerical data , Membranes, Artificial , Polymers/chemistry , Adrenergic beta-Antagonists/pharmacokinetics , Chemical Phenomena , Chemistry, Physical , Computer Simulation , Hydrogels , Models, Theoretical , Propranolol/pharmacokinetics , SolubilitySubject(s)
Insulin/pharmacology , Protease Inhibitors/pharmacology , Vasopressins/pharmacology , Animals , Cell Membrane/drug effects , Cell Membrane/metabolism , Hydrolysis , In Vitro Techniques , Osmosis/drug effects , Rana temporaria , Signal Transduction/drug effects , Urinary Bladder/drug effects , Urinary Bladder/metabolismABSTRACT
Interactions of a number of globular proteins with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide were studied. Under conditions of carbodiimide excess at a protein concentration lower than 88.5 x 10(-5) mol/l, the crosslinking reaction was found to proceed exclusively by an intramolecular mechanism. This resulted in conformational changes in the protein secondary structure and decreased its biological activity. At higher protein concentrations, the reaction of intramolecular crosslinking was always the first to proceed, and only then intramolecularly crosslinked proteins interacted. The reaction of intermolecular crosslinking was not followed by a further change in the protein conformation and activity.
Subject(s)
Carbodiimides/chemistry , Globulins/chemistry , Solubility , WaterABSTRACT
Conjugates of insulin with duck egg-white ovomucoid and soybean trypsin inhibitor were synthesized. The conjugates are highly stable to alpha-chymotrypsin treatment. Oral administration of insulin-ovomucoid conjugates in rabbits significantly lowered blood glucose level unlike administration of insulin-soybean trypsin conjugate.
Subject(s)
Enzyme Inhibitors/pharmacology , Insulin/chemical synthesis , Orosomucoid/pharmacology , Trypsin Inhibitor, Kunitz Soybean/pharmacology , Animals , Blood Glucose/analysis , Ducks , Insulin/pharmacology , RabbitsABSTRACT
Collagenolytic protease from hepatopancreas of king crab was immobilized on water-soluble reactive polymers containing N-succinimide units and possessing different hydrophobicity-hydrophilicity balance. The immobilized enzyme displayed higher heat stability, but its proteolytic activity decreased with the increase in the number of the copolymer hydrophobic groups. Highly active thermostable preparations of collagenolytic protease were obtained by copolymerization. The copolymerization did not affect the enzyme activity and increased the protease heat stability to the formation of pseudocross-links of protein molecules in their associates.
Subject(s)
Brachyura/enzymology , Collagenases/chemistry , Enzymes, Immobilized/chemistry , Animals , Collagenases/isolation & purification , Collagenases/metabolism , Enzyme Stability , Enzymes, Immobilized/metabolism , PolymersABSTRACT
The biospecific antiproteinase haemosorbent (BAH) 'Ovosorb' containing, in the bulk of polyacryamide gel, the ovomucoid from whites of duck eggs, was used for a complex treatment of the experimental generalized purulent peritonitis and acute destructive pancreatitis in dogs. The efficiency of BAH was manifested in the significant reduction of lethality of the experimental animals, a more rapid liquidation of proteinasaemia, normalization in plasma of alpha 1-proteinase inhibitor and protein metabolism. Thus, by eliminating proteinases from circulation, Ovosorb contributes to the cessation of imbalance in the proteinase-inhibitor system and is efficient in the therapy of pathological states related to this imbalance.
Subject(s)
Ovomucin/therapeutic use , Pancreatitis/drug therapy , Peritonitis/drug therapy , Protease Inhibitors/therapeutic use , Acute Disease , Animals , Dogs , Pancreatitis/metabolism , Peritonitis/metabolism , SuppurationSubject(s)
Adamantane/pharmacokinetics , Pseudomonas putida/metabolism , Rhodotorula/metabolism , Adamantane/analogs & derivatives , Biotransformation , Camphor 5-Monooxygenase , Chromatography, Gas , Cytochrome P-450 Enzyme System/metabolism , Magnetic Resonance Spectroscopy , Mass Spectrometry , Mixed Function Oxygenases/metabolism , Pseudomonas putida/enzymology , Rhodotorula/enzymologyABSTRACT
A method of covalent immobilization of microorganisms (marine luminescent bacteria and yeast) in polymeric hydrogels is described. It is shown that cell immobilization leads to the creation of materials having properties of both synthetic polymers and physiologically active systems. Application of systems containing covalent immobilized yeast and photobacteria in biotechnological and other processes is proposed.
Subject(s)
Photobacterium/metabolism , Saccharomyces cerevisiae/metabolism , Acetates/metabolism , Biotechnology/methods , Carbon Radioisotopes , Cell Membrane/metabolism , Chlorides/metabolism , Cross-Linking Reagents , Gels , Iodine Radioisotopes , Kinetics , Luminescent Measurements , Polymers , Sodium Iodide/metabolismABSTRACT
Sorbents for the removal of proteolytic enzymes from biological fluids were synthesized by immobilization of proteinase inhibitor, ovomucoid from duck egg white, in polymeric hydrogel matrix. The immobilization of the protein inhibitor modified by acryloyl chloride occurs during copolymerization of the unsaturated derivative of inhibitor with hydrophilic monomer and crosslinking agent. It was shown that the sorbent obtained possesses a high affinity for proteinases and is haemocompatible. The use of the haemosorbent for eliminating excess activated proteinase from blood is proposed.
Subject(s)
Biocompatible Materials/chemical synthesis , Hemoperfusion , Protease Inhibitors , Animals , Endopeptidases/blood , Endopeptidases/isolation & purification , Gels , Materials Testing , OvomucinABSTRACT
The interaction of ovomucoid proteinase inhibitor prepared from duck egg white with a dextran of a molecular weight of 70,000 preliminary treated with potassium periodate. Irrespective of the number of the sites of the ovomucoid binding to aldehyde-dextran the anti-chymotryptic activity is equal to that of the native inhibitor, while the antitryptic activity decreases proportionally to the number of ovomucoid amino groups involved in the reaction with dextran. When a few ovomucoid molecules are immobilized on the polysaccharide macromolecule the perturbing effect of the protein-protein interactions is minimal, as the rigid polymeric chain prevents from the formation of associates of proteins immobilized on this backbone.