Prolonging the In Vivo Residence Time of Prostaglandin E1 with Biodegradable Nanoparticles

2008 ◽  
Vol 25 (7) ◽  
pp. 1686-1695 ◽  
Author(s):  
Tsutomu Ishihara ◽  
Miyuki Takahashi ◽  
Megumu Higaki ◽  
Mitsuko Takenaga ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Residence Time ◽  
Prostaglandin E1 ◽  
Biodegradable Nanoparticles

The Filter Loop Technique as a Method of Measuring Platelet Aggregation in the Flowing Blood of the Rat; the Inhibitory Activity of 5-oxo-l-cyclopentene-l-heptanoic Acid (AY-16,804) on Platelet Aggregation

1973 ◽  
Vol 30 (01) ◽  
pp. 138-147 ◽  
Author(s):  
Christopher R. Muirhead
Keyword(s):  
Platelet Aggregation ◽  
Prostaglandin E1 ◽  
Suitable Model ◽  
Heptanoic Acid ◽  
Simple Method ◽  
Loop Technique ◽  
Flowing Blood ◽  
Filter Loop

SummaryThe filter loop technique which measures platelet aggregation in vivo in the flowing-blood of the rat was compared to the optical density technique of Born which is carried out in vitro with platelet rich plasma. Using these two experimental models the effect on platelet aggregation of three known inhibitors sulfinpyrazone, dipyridamole and prostaglandin E1, and a novel compound 5-oxo-l-cyclopentene-l-heptanoic acid (AY-16, 804) was determined.The effects on platelet aggregation of the known inhibitors were consistent with information in the literature. Prostaglandin E1 was the most potent inhibitor in both techniques; sulfinpyrazone inhibited aggregation in both models but was less potent than prostaglandin E1. AY-16, 804 exhibited activity in vitro and in vivo similar to that of sulfinpyrazone. Dipyridamole did not inhibit platelet aggregation in vivo and did not inhibit aggregation in vitro in concentrations at which it remained soluble.The filter loop technique is a suitable model for measuring platelet aggregation in the flowing blood of the rat. It is a relatively simple method of determining aggregation and easily adapted to other species.

scholarly journals Formulation and evaluation of effervescent floating tablets of tizanidine hydrochloride

2011 ◽  
Vol 61 (2) ◽  
pp. 217-226 ◽  
Author(s):  
Komuravelly Someshwar ◽  
Kalyani Chithaluru ◽  
Tadikonda Ramarao ◽  
K. Kumar
Keyword(s):  
Drug Release ◽  
Residence Time ◽  
Release Kinetics ◽  
Hydroxypropyl Methylcellulose ◽  
Matrix Tablets ◽  
Physical Parameters ◽  
Floating Tablets ◽  
Gastric Residence Time

Formulation and evaluation of effervescent floating tablets of tizanidine hydrochloride Tizanidine hydrochloride is an orally administered prokinetic agent that facilitates or restores motility through-out the length of the gastrointestinal tract. The objective of the present investigation was to develop effervescent floating matrix tablets of tizanidine hydrochloride for prolongation of gastric residence time in order to overcome its low bioavailability (34-40 %) and short biological half life (4.2 h). Tablets were prepared by the direct compression method, using different viscosity grades of hydroxypropyl methylcellulose (HPMC K4M, K15M and K100M). Tablets were evaluated for various physical parameters and floating properties. Further, tablets were studied for in vitro drug release characteristics in 12 hours. Drug release from effervescent floating matrix tablets was sustained over 12 h with buoyant properties. DSC study revealed that there is no drug excipient interaction. Based on the release kinetics, all formulations best fitted the Higuchi, first-order model and non-Fickian as the mechanism of drug release. Optimized formulation (F9) was selected based on the similarity factor (f2) (74.2), dissolution efficiency at 2, 6 and 8 h, and t50 (5.4 h) and was used in radiographic studies by incorporating BaSO4. In vivo X-ray studies in human volunteers showed that the mean gastric residence time was 6.2 ± 0.2 h.

Preclinical Assessment of Nanostructured Liquid Crystalline Particles for the Management of Bacterial Keratitis: in-vivo and Pharmacokinetics Study

2021 ◽  
Author(s):  
Shreya Kaul ◽  
Upendra Nagaich ◽  
Navneet Verma
Keyword(s):  
Residence Time ◽  
Liquid Crystalline ◽  
Ex Vivo ◽  
Research Work ◽  
Poloxamer 407 ◽  
Pharmacokinetic Studies ◽  
Eye Drops ◽  
Statistical Experimental Design ◽  
Bacterial Keratitis

Abstract The research work was driven to develop novel nanostructured liquid crystalline particles of vancomycin for its improved pre-ocular residence time, ocular bio-availability, enhanced targeting, increased permeability, reduced dosing frequency, controlled drug release and reduced systemic side-effects. Formulation was developed by fragmenting cubic crystalline phase of glycerol monooleate, water and poloxamer 407. A four-factor, three-level Taguchi statistical experimental design was constructed to optimize the formulation. Formulations exhibited internal-cubic structure of the vesicles with particle size in the range of 51.11 ± 0.96 nm to 158.73 ± 0.46 nm and negative zeta potential. Ex-vivo transcorneal permeation studies demonstrated that the optimized cubosomes had 2.4-fold increase in apparent permeability co-efficient as compared to vancomycin solution. Whereas, in-vivo studies in rabbits demonstrated that the severity of keratitis was considerably lowered in day 3 with optimized cubosomes. Ocular pharmacokinetic studies evaluated level of drug in aqueous humor and results revealed that the time to peak concentration (Tmax) of vancomycin loaded cubosomal formulation was about 1.9-fold higher and mean residence time was 2.2-fold greater than vancomycin solution. Furthermore, histological examination revealed that the corneal layers displayed well-maintained morphology without any stromal swelling, consequently indicating safety of formulation. In conclusion, results manifested that the developed vancomycin loaded cubosomes could be a promising novel ocular carrier and an ideal substitute for conventional eye-drops for the management of bacterial-keratitis.

scholarly journals Single molecule tracking of Ace1p in Saccharomyces cerevisiae defines a characteristic residence time for non-specific interactions of transcription factors with chromatin

2016 ◽  
Vol 44 (21) ◽  
pp. e160-e160 ◽  
Author(s):  
David A Ball ◽  
Gunjan D Mehta ◽  
Ronit Salomon-Kent ◽  
Davide Mazza ◽  
Tatsuya Morisaki ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Residence Time ◽  
Single Molecule ◽  
Specific Binding ◽  
Underlying Mechanism ◽  
Specific Interactions ◽  
Single Molecule Tracking ◽  
Reliable Performance ◽  
Transient Interactions

Abstract In vivo single molecule tracking has recently developed into a powerful technique for measuring and understanding the transient interactions of transcription factors (TF) with their chromatin response elements. However, this method still lacks a solid foundation for distinguishing between specific and non-specific interactions. To address this issue, we took advantage of the power of molecular genetics of yeast. Yeast TF Ace1p has only five specific sites in the genome and thus serves as a benchmark to distinguish specific from non-specific binding. Here, we show that the estimated residence time of the short-residence molecules is essentially the same for Hht1p, Ace1p and Hsf1p, equaling 0.12–0.32 s. These three DNA-binding proteins are very different in their structure, function and intracellular concentration. This suggests that (i) short-residence molecules are bound to DNA non-specifically, and (ii) that non-specific binding shares common characteristics between vastly different DNA-bound proteins and thus may have a common underlying mechanism. We develop new and robust procedure for evaluation of adverse effects of labeling, and new quantitative analysis procedures that significantly improve residence time measurements by accounting for fluorophore blinking. Our results provide a framework for the reliable performance and analysis of single molecule TF experiments in yeast.

LEUKOTRIENES INDUCE THE ACUTE RELEASE OF TISSUE-TYPE PLASMINOGEN ACTIVATOR FROM PERFUSED RAT BLOOD VESSEL WALLS

1987 ◽  
Author(s):  
N Tranquille ◽  
J J Emeis
Keyword(s):  
Blood Vessel ◽  
Plasminogen Activator ◽  
Prostaglandin E1 ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Acute Increase ◽  
Vessel Walls ◽  
Isolated Rat

In a previous publication (Blood 66, 86, 1985) we suggested, on the basis of inhibitor experiments, that lipoxygenase metabolites might be involved in the release of tissue-type plasminogen activator (t-PA) from vessel walls. To test this suggestion, isolated rat hindlegs were freed of blood with Tyrode-BSA solution, and subsequently perfused with Tyrode-BSA containing various lipoxygenase metabolites. The perfusate was collected at timed intervals and assayed for t-PA activity by a spectrophoto-metric procedure. Of the compounds tested (see Table) 5-HETE did not induce PA release. However, leukotriene (LT) C4 and LTD4 dose-dependently (10-200 nM) induced the release of t-PA, which plateaued at 160 and 200 nM, respectively. Peak levels of t-PA activity were found at one minute, although the amount of t-PA released was less than that induced by PAF-acether. The PA activity released proved to be t-PA by functional and immunological criteria. Release of t-PA induced by LTC4 and LTD 4 was inhibited by the LT receptor antagonist FPL-55712 (10 μM).Prostaglandin E1 and E2, prostacyclin and ZK 36374 did not induce acute t-PA release at 0.1-2.8 μM concentrations in our model. LTC4 and LTD4 also induced an acute increase of t-PA activity in vivo in rats at a dosage of 2 μg/kg i.v.The data show that LTC4 and LTD4 can directly induce the acute release of t-PA, possibly by interacting with an endothelial LT receptor.

scholarly journals The importance of load-independent analysis in assessment of the inotropic effect of prostaglandin E1 in vivo

1988 ◽  
Vol 95 (3) ◽  
pp. 432-441 ◽  
Author(s):  
Louis A. Brunsting ◽  
David R. Salter ◽  
Charles E. Murphy ◽  
Anwar S. Abd-Elfattah ◽  
Jacques P. Goldstein ◽  
...  
Keyword(s):  
Prostaglandin E1 ◽  
Inotropic Effect ◽  
Independent Analysis

scholarly journals Effects of prostaglandin E1 on platelet loss during in vivo and in vitro extracorporeal circulation with a bubble oxygenator

1979 ◽  
Vol 77 (1) ◽  
pp. 119-126 ◽  
Author(s):  
V. Paul Addonizio ◽  
Jerome F. Strauss ◽  
Robert W. Colman ◽  
L. Henry Edmunds
Keyword(s):  
Extracorporeal Circulation ◽  
Prostaglandin E1 ◽  
Bubble Oxygenator

scholarly journals HA-based dermal filler: downstream process comparison, impurity quantitation by validated HPLC-MS analysis, and in vivo residence time study

2019 ◽  
Vol 17 (3) ◽  
pp. 228080001986707 ◽  
Author(s):  
Cristian Guarise ◽  
Carlo Barbera ◽  
Mauro Pavan ◽  
Susi Panfilo ◽  
Riccardo Beninatto ◽  
...  
Keyword(s):  
Residence Time ◽  
Rabbit Model ◽  
Diglycidyl Ether ◽  
In Vitro Cytotoxicity ◽  
Dermal Filler ◽  
Dermal Fillers ◽  
Process Comparison ◽  
Hygroscopic Properties

The success of hyaluronic acid (HA)-based dermal fillers, with more than 2 million minimally invasive procedures conducted in 2016 in the US alone, is due to their hygroscopic properties of biocompatibility and reversibility. The type and density of HA cross-linkage, as well as the manufacturing technology, may influence not only the in vivo persistence but also the safety profile of dermal fillers. 1,4-Butanediol diglycidyl ether (BDDE) is the cross-linker used in most market-leading HA fillers; 1,4-butanediol di-(propan-2,3-diolyl) ether (BDPE) is the major impurity obtained from the HA–BDDE cross-linking (HBC) process. In this work, a new process to obtain high purity HBC fillers was developed. A new HPLC-MS method was validated for the quantification of BDPE content in HBC dermal fillers. In vitro cytotoxicity of BDPE was evaluated in fibroblasts (IC50 = 0.48 mg/mL). The viscoelasticity was monitored during the shelf-life of the HBC-10% hydrogel and was correlated with in vitro hyaluronidase resistance and in vivo residence time in a rabbit model. This analysis showed that elasticity is the best parameter to predict the in vivo residence time. Finally, a series of parameters were investigated in certain marketed dermal fillers and were compared with the results of the HBC-10% hydrogel.

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