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Vitro Properties (vitro + property)
Selected AbstractsComparative evaluation of quality of doxycycline formulations registered in Estonia to those registered in the Russian FederationDRUG DEVELOPMENT RESEARCH, Issue 2 2008A. Meos Abstract The in vitro properties of four Estonian drug market (manufactured in Austria, Germany, and Finland) and four Russian Federation drug market (manufactured in Belarussia and Russian Federation) doxycycline formulations were evaluated using the estimation of the quantitative content and purity of the active pharmaceutical ingredient (API) and the dissolution test. Tolerance limits were set according to the European Pharmacopoeia (for the content and purity of the API) and USP (for the dissolution test) doxycycline monographs. All Estonian drug market doxycycline formulations complied with the tolerance limits in all tests and assays. Most of the Russian Federation drug market doxycycline formulations also passed the tolerance limits, with two minor exceptions: one formulation contained quantitatively API below the USP limit (83.7% instead of the 90%), but all the API was readily released in the dissolution test, the other formulation (capsules) released 80% of API in 39,min instead of 30,min. The general conclusion of the study is that despite some deviations, the Russian Federation drug market doxycycline formulations are comparable with those purchased from the Estonian drug market. Drug Dev Res 69: 58,68, 2008. © 2008 Wiley-Liss, Inc. [source] Evaluation of in vitro properties of di-tri-octahedral smectite on clostridial toxins and growthEQUINE VETERINARY JOURNAL, Issue 7 2003J. S. Weese Summary Reasons for performing study: Clostridial colitis and endotoxaemia of intestinal origin are significant causes of morbidity and mortality in horses. Intestinal adsorbents are available for treatment of these conditions; however, little information exists supporting their use. Objectives: To evaluate the ability of di-tri-octahedral smectite to bind to Clostridium difficile toxins A and B, C. perfringens enterotoxin and endotoxin, inhibit clostridial growth and the actions of metronidazole in vitro. Methods: Clostridium difficile toxins, C. perfringens enterotoxin and endotoxin were mixed with serial dilutions of di-tri-octahedral smectite, then tested for the presence of clostridial toxins or endotoxin using commercial tests. Serial dilutions of smectite were tested for the ability to inhibit growth of C. perfringens in culture broth, and to interfere with the effect of metronidazole on growth of C. perfringens in culture broth. Results: Clostridium difficile toxins A and B, and C. perfringens enterotoxin were completely bound at dilutions of 1:2 to 1:16. Partial binding of C. difficile toxins occurred at dilutions up to 1:256 while partial binding of C. perfringens enterotoxin occurred up to a dilution of 1:128. Greater than 99% binding of endotoxin occurred with dilutions 1:2 to 1:32. No inhibition of growth of C. difficile or C. perfringens was present at any dilution, and there was no effect on the action of metronidazole. Conclusions: Di-tri-octahedral smectite possesses the ability to bind C. difficile toxins A and B, C. perfringens enterotoxin and endotoxin in vivo while having no effect on bacterial growth or the action of metronidazole. Potential relevance: In vivo studies are required to determine whether di-tri-octahedral smectite might be a useful adjunctive treatment of clostridial colifis and endotoxaemia in horses. [source] Vinylic telluride derivatives as promising pharmacological compounds with low toxicityJOURNAL OF APPLIED TOXICOLOGY, Issue 7 2008V. C. Borges Abstract The aim of the present study was to evaluate pharmacological and toxicological properties of (Z)-2-(methylthio)-1-(butyltelluro)-1-phenylethene 1a, (Z)-1-(4-methylphenylsulfonyl)-2-(phenyltelluro)-2-phenylethene 1b, (Z)-2-(butyltelluro)-1-(benzylthio)-1-heptene 1c and (Z)-2-(phenylthio)-1-(butyltelluro)-1-phenylethene 1d. In vitro, vinylic telluride derivatives 1a, 1d and 1c were more effective in reducing lipid peroxidation than compound 1b. The maximal inhibitory effect of vinylic telluride derivatives on lipid peroxidation was in the following order: 1a = 1d > 1c > 1b. Compound 1b was more potent in inhibiting , -ALA-D activity (, -aminolevulinate dehydratase) than compounds 1c and 1d. Based on the in vitro properties presented by compounds 1a (an antioxidant) and 1b (a pro-oxidant), toxicological parameters were assessed in vivo and ex vivo in rats. Calculated LD50 of compounds 1a and 1b, administered by oral route, were 20.5 and 1.44 µmol kg,1, respectively. Compound 1b induced behavioral alterations in the open field test. Renal and spleenic , -ALA-D activities were inhibited in rats treated orally with compound 1a. Compound 1b stimulated , -ALA-D activity in liver and spleen of rats. Rats treated with compound 1b had increased hepatic, renal and spleenic lipid peroxidation. Renal and hepatic markers were not altered when compounds 1a and 1b were administered to rats at doses of around LD50, while compound 1a at high doses changed aspartate aminotransferase activity and urea levels. Based on in vitro results, this study demonstrated that compounds 1a and 1d are promising antioxidant compounds. Ex vivo data reinforce compound 1a as a promising drug for more detailed pharmacological studies. Copyright © 2008 John Wiley & Sons, Ltd. [source] Apixaban, an oral, direct and highly selective factor Xa inhibitor: in vitro, antithrombotic and antihemostatic studiesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2008P. C. WONG Summary.,Background:,Apixaban is an oral, direct and highly selective factor Xa (FXa) inhibitor in late-stage clinical development for the prevention and treatment of thromboembolic diseases. Objective:,We evaluated the in vitro properties of apixaban and its in vivo activities in rabbit models of thrombosis and hemostasis. Methods:,Studies were conducted in arteriovenous-shunt thrombosis (AVST), venous thrombosis (VT), electrically mediated carotid arterial thrombosis (ECAT) and cuticle bleeding time (BT) models. Results:,In vitro, apixaban is potent and selective, with a Ki of 0.08 nm for human FXa. It exhibited species difference in FXa inhibition [FXa Ki (nm): 0.16, rabbit; 1.3, rat; 1.7, dog] and anticoagulation [EC2× (,m, concentration required to double the prothrombin time): 3.6, human; 2.3, rabbit; 7.9, rat; 6.7, dog]. Apixaban at 10 ,m did not alter human and rabbit platelet aggregation to ADP, ,-thrombin, and collagen. In vivo, the values for antithrombotic ED50 (dose that reduced thrombus weight or increased blood flow by 50% of the control) in AVST, VT and ECAT and the values for BT ED3× (dose that increased BT by 3-fold) were 0.27 ± 0.03, 0.11 ± 0.03, 0.07 ± 0.02 and > 3 mg kg,1 h,1 i.v. for apixaban, 0.05 ± 0.01, 0.05 ± 0.01, 0.27 ± 0.08 and > 3 mg kg,1 h,1 i.v. for the indirect FXa inhibitor fondaparinux, and 0.53 ± 0.04, 0.27 ± 0.01, 0.08 ± 0.01 and 0.70 ± 0.07 mg kg,1 day,1 p.o. for the oral anticoagulant warfarin, respectively. Conclusions:,In summary, apixaban was effective in the prevention of experimental thrombosis at doses that preserve hemostasis in rabbits. [source] Evaluation of a Non-Woven Fabric Coated with a Chitosan Bi-Layer Composite for Wound DressingMACROMOLECULAR BIOSCIENCE, Issue 5 2008Bai-Shuan Liu Abstract This study presents a novel design of an easily stripped bi-layer composite that consists of an upper layer of a soybean protein non-woven fabric coated with a lower layer, a genipin-crosslinked chitosan film, as a wound dressing material. This study examines the in vitro properties of the genipin-crosslinked chitosan film and the bi-layer composite. Furthermore, in vivo experiments are conducted to study wounds treated with the composite in a rat model. Experimental results show that the degree of crosslinking and the in vitro degradation rate of the genipin-crosslinked chitosan films can be controlled by varying the genipin contents. In addition, the genipin contents should exceed 0.025 wt.-% of the chitosan-based material if complete crosslinking reactions between genipin and chitosan molecules are required. Water contact angle analysis shows that the genipin-crosslinked chitosan film is not highly hydrophilic; therefore, the genipin-crosslinked chitosan layer is not entangled with the soybean protein non-woven fabric, which forms an easily stripped interface layer between them. Furthermore, this new wound dressing material provides adequate moisture, thereby minimizing the risk of wound dehydration, and exhibits good mechanical properties. The in vivo histological assessment results reveal that epithelialization and reconstruction of the wound are achieved by covering the wound with the composite, and the composite is easily stripped from the wound surface without damaging newly regenerated tissue. [source] The chemistry behind redox regulation with a focus on sulphur redox systemsPHYSIOLOGIA PLANTARUM, Issue 3 2008Claus Jacob Sulphur metabolism in plants provides a wealth of natural products, including several chemically unusual substances, such as thiosulphinates, polysulphides and isothiocyanates. Many of these reactive sulphur species (RSS) exhibit a distinct redox behaviour in vitro, which translates into a rather interesting biological activity in vivo, such as antibiotic, fungicidal, pesticidal or anticancer activity. While the molecular basis for such activity has long remained obscure, research into sulphur-based redox systems during the past 5,10 years has achieved a better knowledge of the in vitro properties of RSS and has led to an improved understanding of their impact on intracellular redox signalling and control pathways in living cells. It has become apparent that the redox chameleon sulphur occurs in biological systems in about 10 different oxidation states, which give rise to an extensive and complicated network of sulphur-based redox events. Together, natural sulphur products from plants and their intracellular targets provide the basis for innovative design of novel antibiotics, fungicides, pesticides and anticancer agents. [source] | ||||||||||