Hyaluronan (HA), a natural glycoaminoglycan featuring an extracellular matrix, has been suggested as an effective biocompatible material. In this study, the effectiveness of HA microparticles as a carrier system for antibiotics was evaluated, and their physicochemical characteristics were determined. Microparticles were fabricated by the gelation of sulfadiazine (SD) loaded HA solution with calcium chloride through either a granulation (GR-microparticles) or encapsulation (EN-microparticles) process, and atelocollagen was incorporated into the microparticles as an additive in order to improve their physical properties. The characteristics of the microparticles were examined by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and swelling test. In vitro release experiments were performed for 7 days and the released amount of SD was determined using high-performance liquid chromatography (HPLC). Microscopic observations revealed that the collagen incorporated HA particles had a more compact surface than the HA particles. DSC analysis determined a loss of SD crystallinity in the particles. Calcium chloride retarded the swelling of particles, whereas the loaded drug contents did not affect this property. Both GR-and EN-microparticles sustained SD release with initial bursting effect. SD release from EN-microparticles was faster than from GR- microparticles. In addition, the release rate was dependent on the SD content in the microparticles. These results suggest that collagen modified HA microparticles have a potential as a release rate controlling material for crystalline drugs such as SD.
Antibiotics/*administration & dosage ; Calcium Chloride/pharmacology ; Collagen/*pharmacology ; *Drug Carriers ; Hyaluronic Acid/*administration & dosage ; Sulfadiazine/administration & dosage

AIMTo study unitary-core osmotic pump tablet for delivering water-insoluble drug for 24 hours.

METHODSUnitary-core osmotic pump tablet was prepared using nifedipine as the model drug. The effects of various core formulation variables on drug release were studied.

RESULTSPolyethylene oxide and potassium chloride have comparable positive effects on drug release, whereas, nifedipine has markedly negative effect on drug release.

CONCLUSIONUnitary-core osmotic pump tablet is very easy in preparation and it can deliver water-insoluble drug in substantially constant rate for 24 hours.

Calcium Channel Blockers ; administration & dosage ; chemistry ; Delayed-Action Preparations ; Drug Delivery Systems ; Nifedipine ; administration & dosage ; chemistry ; Osmosis ; Polyethylene Glycols ; pharmacology ; Potassium Chloride ; pharmacology ; Solubility ; Tablets ; Technology, Pharmaceutical ; methods

OBJECTIVETo study the effects of total flavone of Abelmoschl Manihot L. Medic (TFA) on the function of platelets and to explore its mechanism.

METHODSRat models of artery-veins bypassing thrombus formation were used. The platelets of rabbits were collected. Platelet aggregation was induced by collagen and intracellular calcium ion concentration ([Ca(2+)]i) was assayed by Fura-2 method.

RESULTSTFA (25, 50, 100 mg/kg) significantly and dose-dependently reduced the weight of thrombus. TFA (0.025, 0.05, 0.1 mg/ml) possessed dose-dependant inhibitory effects on rabbits' platelet aggregation induced by collagen. TFA significantly reduced the resting and CaCl(2)-induced increase of free intracellular calcium concentration ([Ca(2+)]i) in rabbit platelet in vitro.

CONCLUSIONTFA has an antiplatelet effect via the inhibition on the influx of Ca(2+).

Animals ; Blood Platelets ; drug effects ; Calcium ; blood ; Calcium Channel Blockers ; administration & dosage ; pharmacology ; Calcium Chloride ; pharmacology ; Carotid Artery Thrombosis ; blood ; etiology ; Collagen ; pharmacology ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; Flavones ; administration & dosage ; pharmacology ; Glycosides ; administration & dosage ; pharmacology ; Intracellular Membranes ; metabolism ; Osmolar Concentration ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; administration & dosage ; pharmacology ; Platelet Function Tests ; Rabbits ; blood ; Rats ; Rats, Wistar

OBJECTIVE: To explore the objective evidence of the corpus biochemical changes in rabbits for postmortem diagnosis of potassium intoxication. METHODS: Rabbits were sacrificed by Infusion of 0.3% KCl at full speed push or 1% KCl at 100 drip/min, respectively, with normal rabbits used as control. Cardiac blood and urine samples were collected before and after potassium infusion to examine the concentrations of various electrolytes (K+, Na+, Ca2+, Mg2+, Cl-, and HCO3-) and to observe the antemortem and postmortem biochemical changes. RESULTS: The mean lethal infusion time in the 0.3%KCl group was longer than that in the 1% KCl group (P = 0.006). The serum concentration of K+ increased while the serum concentrations of Na+, Ca2+, Cl-, and HCO3- decreased after the infusion. There were no statistically significant differences in the whole blood concentration of K+ as well as the serum concentration of Mg2+ between the two groups (P = 0.062). There were statistically significant differences in the concentrations of whole blood K+, as well as serum Na+, Mg2+, and Cl-, but not in the serum K+, Ca2+, and HCO3-. There were no statistically significant differences seen in the urine volumes and the concentrations of all the urine electrolytes between the groups. CONCLUSION Examination of the concentrations of K+ both in the whole blood and serum, as well as Mg2+ in the serum may be helpful for postmortem diagnosis of potassium intoxication.
Animals ; Calcium/urine* ; Electrolytes/urine* ; Forensic Medicine/methods* ; Injections, Intravenous/methods* ; Magnesium/urine* ; Male ; Postmortem Changes ; Potassium/poisoning* ; Potassium Chloride/administration & dosage* ; Rabbits ; Sodium/urine*

Brief ischemic episodes that induce myocardial and coronary endothelial dysfunction may alter the responses to inotropic drugs. To determine the effects of inotropic drugs in stunned myocardium, the coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and regional mechanical function in response to intracoronary dobutamine, epinephrine, amrinone, and calcium chloride (CaCl2) were measured before (normal) and 30 min after a 15-min-period occlusion of the left anterior descending artery (stunned) in an open-chest canine model. Percent segment shortening (%SS) and post-systolic shortening (%PSS) were determined. Myocardial extraction of oxygen (EO2) and lactate (E(lac)) was calculated. The inotropic drugs increased %SS, CBF, and MVO2 in normal myocardium. Epinephrine and amrinone decreased, while dobutamine and CaCl2 did not affect EO2. The ischemia and reperfusion itself significantly reduced %SS and E(lac), and increased %PSS. In stunned myocardium, the responses to inotropic drugs were not significantly altered, except that they progressively reduced %PSS and epinephrine did not affect EO2. These findings indicate that a brief episode of ischemia does not affect the mechanical and metabolic coronary flow responses to inotropic drugs, although it abolishes direct vasodilator responses to epinephrine.
Amrinone/administration and dosage ; Animals ; Calcium Chloride/administration and dosage ; Cardiotonic Agents/*administration and dosage ; Comparative Study ; Dobutamine/administration and dosage ; Dogs ; Dose-Response Relationship, Drug ; Epinephrine/administration and dosage ; Female ; Male ; Myocardial Contraction/*drug effects ; Myocardial Stunning/*drug therapy/etiology/*physiopathology ; Oxidation-Reduction/drug effects ; Oxygen Consumption/*drug effects ; Reperfusion Injury/complications/*drug therapy/*physiopathology ; Treatment Outcome

OBJECTIVETo investigate the relaxative characteristics of resveratrol on thoracic aortic artery in the rat and its mechanism.

METHODWe perfused the isolated rings and observed the response of NA-induced artery contraction to resveratrol under the Ca2+-contained and Ca2+-free bath solutions. In the same way were the effect of reveratrol on the vascular smooth muscle observed by adding two different concentration of KCl (30 and 80 mmol x L(-1)), and the effect on the contraction of the vascular smooth muscle depending on the intracellular calcium and extracellular calcium were also observed by adding NA. We also observed the effect of resveratrol on the contraction of rings induced by NA in the presence of L-NNA and Glibenclamide.

RESULTResveratrol relaxed rat aorta rings precontracted by NA in a dose-dependent manner. The relaxant effect of resveratrol on the rat rings of endothelium-denuded group was reduced compared with that of endothelium-intact group; the relaxant effect of resveratrol on rat rings was higher under the condition of Ca2+-free bath solution than that under the condition of Ca2+-contained bath solution. Resveratrol had a repressive effect on the aorta's contraction induced by intracellular calcium, but had no effect induced by extracellular calcium. Resveratrol relaxed the contractions induced by KCl 30 mmol x L(-1) as well as KCl 80 mmol x L(-1), but the contraction curve of KCl 80 mmol x L(-1) was shifted upward significantly. In the L-NNA group, the relaxant effect was attenuated by (26.0 +/- 4.6) %; but there was no change in the group of Glibenclamide ( P > 0.05).

CONCLUSIONThe results indicate that resveratrol relaxes vascular smooth muscle in an endothelium dependent manner. The mechanisms for this phenomenon seem to be related with promoting synthesis and release of NO, opening Ca2+ activated K+ channel (KCa channel) as well as the inhibition of Ca2+ influx and release of Ca2+ from intracellular stores.

Animals ; Aorta, Thoracic ; drug effects ; physiology ; Calcium ; metabolism ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; Endothelium, Vascular ; physiology ; Female ; Glyburide ; pharmacology ; Male ; Muscle Contraction ; drug effects ; Muscle, Smooth, Vascular ; drug effects ; physiology ; Norepinephrine ; antagonists & inhibitors ; Potassium Chloride ; antagonists & inhibitors ; Random Allocation ; Rats ; Rats, Wistar ; Stilbenes ; administration & dosage ; pharmacology ; Vasodilator Agents ; administration & dosage ; pharmacology

OBJECTIVEHypoxia/KCl injury model in the cultured neonatal rat cardiomyocytes (CMs) was established to investigate the protective effect of Lycium barbanun Glycopeptide (LbGp) on calcium overload.

METHODCultured neonatal rat CMs were divided into three groups, namely normal control, hypoxia groups and LbGp-treated group. CMs in LbGp-treated group and hypxia group were cultured in an incubator ventilated with 95% N2 and 5% CO2 with or without LbGP. CMs viability under hypoxia was measured by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide colorimetry (MTT). The intracellular free calcium concentration in cardiomyocytes was measured by laser confocal microscope with Fura-3/AM as a calcium indicator. The protective effects of LbGp on the CMs treated by KCl (60 mmol x L(-1)) was observed.

RESULTAs compared with normal controls, the degree of MTT metabolism was significantly reduced (P < 0.01) in hypoxic group and slightly reduced in LbGp (P < 0.05). Hypoxia-induced enhancement of intracellular calcium ([Ca2+]i) was attenuated by LbGp significantly (P < 0.01). Moreover, KCl-induced enhancement of [Ca2+]i was also reduced by LbGp at the doses of 25, 50, 100 microg x mL(-1) in a concentration-dependent manner.

CONCLUSIONThe result suggested that LbGp is able to increase the survival ratio and inhibit the enhancement of the intracellular free calcium concentration in cardiomyocytes induced by hypoxia and high potassium. One of the mechanisms is that LbGp acts on L-type calcium channels.

Animals ; Animals, Newborn ; Calcium ; metabolism ; Cell Hypoxia ; Cells, Cultured ; Dose-Response Relationship, Drug ; Glycopeptides ; administration & dosage ; isolation & purification ; pharmacology ; Lycium ; chemistry ; Myocytes, Cardiac ; cytology ; metabolism ; Plants, Medicinal ; chemistry ; Potassium Chloride ; Rats ; Rats, Sprague-Dawley

The in situ gel systems can form gel in situ after administration to achieve sustained release, thus provides a promising strategy for drug delivery systems. The aim of this study was to design and prepare in situ gel systems for the oral delivery of ibuprofen (IBU-ISG) and study its pharmacokinetics in Beagle dogs. The characteristics of the basic material of gellan gum (Kelcogel, Kel) and sodium alginate (Manugel, M) were studied through investigating the complex viscosity of the Kel or M solution with or without different concentrations of calcium ion or sodium citrate to ascertain the amount range of the excipients. The measurement of complex viscosity of the solution (0. 5% Kel and 1% M) with different concentrations of sodium citrate and calcium ion was carried out to select the suitable proportion of calcium ion and sodium citrate. The formulation of binary IBU-ISG was optimized by monitoring the complex viscosity before gelling in vitro release property. The optimized formulation contains 1.0% sodium alginate, 0.5% gellan gum, 0. 21% sodium citrate and 0.056% calcium chloride. A single oral dose of IBU-ISG and reference formulation (IBU suspension) were given to each of the 6 healthy Beagle dogs, ibuprofen in plasma at different sampling times was determined by RP-HPLC. The pharmacokinetics parameters in 6 Beagle dogs were calculated. The Tmax of IBU-ISG and reference formulation were (1.8 +/- 0.6) and (0.4 +/- 0. 1) h. The Cmax values were (29.2 +/- 7.6) and (37.8 +/- 2.2) microg x mL(-1). The T(1/2) were (2.3 +/- 0.5) and (2.0 +/- 0.9) h, and the AUC(0-t) were (131.0 +/- 38.6) and (117.3 +/- 23.1) microg x mL(-1) x h, respectively. The binary IBU-ISG was successfully prepared.
Administration, Oral ; Alginates ; chemistry ; Analgesics, Non-Narcotic ; administration & dosage ; blood ; pharmacokinetics ; Animals ; Area Under Curve ; Calcium Chloride ; chemistry ; Citrates ; chemistry ; Delayed-Action Preparations ; Dogs ; Drug Compounding ; methods ; Drug Delivery Systems ; Excipients ; Female ; Glucuronic Acid ; chemistry ; Hexuronic Acids ; chemistry ; Ibuprofen ; administration & dosage ; blood ; pharmacokinetics ; Male ; Polysaccharides, Bacterial ; chemistry ; Viscosity

To study the antiarrhythmic effect of the newly developed alpha/beta-blocker TJ0711, a variety of animal models of arrhythmia were induced by CaCl2, ouabain and ischemia/reperfusion. Glass microelectrode technique was used to observe action potentials of right ventricular papillary muscle of guinea pig. The onset time of arrhythmia induced by CaCl2 was significantly prolonged by TJ0711 at 0.75, 1.5 and 3 mg x kg(-1) doses. TJ0711 (1.5 and 3 mg x kg(-1)) can significantly shorten the ventricular tachycardia (VT) and ventricular fibrillation (VF) duration, the incidence of VF and mortality were significantly reduced. On ischemia-reperfusion-induced arrhythmic model, TJ0711 (0.25, 0.5, 1 and 2 mg x kg(-1)) can significantly reduce the ventricular premature contraction (PVC), VT, VF incidence, mortality, arrhythmia score with a dose-dependent manner. At the same time, rats serum lactate dehydrogenase (LDH) and creatine kinase (CK) activities decreased significantly by TJ0711 (1 and 2 mg x kg(-1)). Ouabain could cause arrhythmia in guinea pigs, when TJ0711 (0.375, 0.75, 1.5 and 3 mg x kg(-1)) was given, the doses of ouabain inducing a variety of arrhythmia PVC, VT, VF, cardiac arrest (CA) were significantly increased with a dose-dependent manner. In the TJ0711 0.1-30 micromol x L(-1) concentration range, guinea pig right ventricular papillary muscle action potential RP (rest potential), APA (action potential amplitude) and V(max) (maximum velocity of depolarization) were not significantly affected. APD20, APD50 and APD90 had a shortening trend but no statistical difference with the increase of TJ0711 concentration. TJ0711 has antiarrhythmic effect on the sympathetic nerve excitement and myocardial cell high calcium animal arrhythmia model. Myocardial action potential zero phase conduction velocity and resting membrane potential were not inhibited by TJ0711. APD20, APD50 and APD90 were shortened by TJ0711 at high concentration. Its antiarrhythmic action mechanism may be besides the action of blocking beta1 receptor, may also have a strong selective blocking action on alpha1 receptor and reducing intracellular calcium concentration.
Action Potentials ; drug effects ; Adrenergic alpha-Antagonists ; administration & dosage ; pharmacology ; Adrenergic beta-Antagonists ; administration & dosage ; pharmacology ; Animals ; Anti-Arrhythmia Agents ; administration & dosage ; pharmacology ; Arrhythmias, Cardiac ; blood ; chemically induced ; etiology ; pathology ; physiopathology ; Calcium Chloride ; Creatine Kinase ; blood ; Dose-Response Relationship, Drug ; Female ; Guinea Pigs ; Heart Ventricles ; cytology ; Lactate Dehydrogenases ; blood ; Male ; Myocardial Reperfusion Injury ; complications ; Myocytes, Cardiac ; drug effects ; physiology ; Ouabain ; Papillary Muscles ; cytology ; Phenoxypropanolamines ; administration & dosage ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effect of Rongshi granule on osteopontin(OPN) expression.

METHODThe urlisthiasis rats were induced by ethylene glycol (EG) and ammonium chloride, the control group rats were non-treated, and the Rongshi granule groups (low-dose group, middle-dose group and high-dose group) were administered Rongshi granule in addition to EG and ammonium chloride in 21 days. Pooled 24 h urine samples from each group were collected weekly with the use of metabolic cages, the concentration of uric calcium and oxalic acid were respectively measured by EDTA and photoelectric colorimetric method. Eight animals from each group were killed at 0, 7, 14, and 21 days, kidneys were histologic examinaed and immunohistochemical staining.

RESULTThe expression of kidney osteopontin in model group was obviously higher than that of control group (P <0.01), and was up to the highest at 21 days with 1.4 times (0.281 3/0.201 8) of the control group. The expression of kidney osteopontin in all of the Rongshi granule groups were lower than those of model group (P < 0.05), with an obvious dose-dependent manner. The degree of the kidney calcium oxalate crystal of the rats in all the Rongshi granule groups was much lower than that of model group, and the uric calcium and oxalic acid were much lower than those of model group (P < 0.01).

CONCLUSIONThe Rongshi granule could inhibit the expression of osteopontin in rat urolithiasis model.

Ammonium Chloride ; Animals ; Calcium ; urine ; Calcium Oxalate ; metabolism ; Dose-Response Relationship, Drug ; Drug Combinations ; Drugs, Chinese Herbal ; administration & dosage ; isolation & purification ; pharmacology ; Ethylene Glycol ; Female ; Kidney ; metabolism ; Kidney Calculi ; chemically induced ; metabolism ; Male ; Osteopontin ; metabolism ; Oxalic Acid ; urine ; Plants, Medicinal ; chemistry ; Random Allocation ; Rats ; Rats, Sprague-Dawley