The ratio of first to zeroth moments of the plasma profile of an oral drug undergoing first-pass and linear reversible metabolism

1995 ◽  
Vol 16 (9) ◽  
pp. 791-796
Author(s):  
Haiyung Cheng
Keyword(s):  
Oral Drug ◽  
Reversible Metabolism ◽  
First Pass ◽  
Plasma Profile

scholarly journals A Critical Appraisal of Solubility Enhancement Techniques of Polyphenols

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Harkiran Kaur ◽  
Gurpreet Kaur
Keyword(s):  
Drug Delivery ◽  
Critical Appraisal ◽  
Oral Drug Delivery ◽  
Aqueous Solubility ◽  
Solubility Enhancement ◽  
Oral Drug ◽  
Natural Substances ◽  
First Pass ◽  
Cellular Dna

Polyphenols constitute a family of natural substances distributed widely in plant kingdom. These are produced as secondary metabolites by plants and so far 8000 representatives of this family have been identified. Recently, there is an increased interest in the polyphenols because of the evidence of their role in prevention of degenerative diseases such as neurodegenerative diseases, cancer, and cardiovascular diseases. Although a large number of drugs are available in the market for treatment of these diseases, however, the emphasis these days is on the exploitation of natural principles derived from plants. Most polyphenols show low in vivo bioavailability thus limiting their application for oral drug delivery. This low bioavailability could be associated with low aqueous solubility, first pass effect, metabolism in GIT, or irreversible binding to cellular DNA and proteins. Therefore, there is a need to devise strategies to improve oral bioavailability of polyphenols. Various approaches like nanosizing, self-microemulsifying drug delivery systems (SMEDDS), microencapsulation, complexation, and solid dispersion can be used to increase the bioavailability. This paper will highlight the various methods that have been employed till date for the solubility enhancement of various polyphenols so that a suitable drug delivery system can be formulated.

scholarly journals A Brief Review on Bucco-adhesive Drug Delivery System

2021 ◽  
Vol 11 (4-S) ◽  
pp. 231-235
Author(s):  
Sabnam Gupta ◽  
Sudip Das ◽  
Abhay Singh ◽  
Suman Ghosh
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Current Status ◽  
Oral Drug ◽  
Adhesive Systems ◽  
First Pass Metabolism ◽  
First Pass ◽  
Bioadhesive Polymers ◽  
Pass Metabolism

The buccal region within the mucosal cavity of the mouth provides an alternative route over an oral drug administration for systemic as well as local drug delivery. As the buccal mucosa has an abundant blood supply and is relatively permeable, it can be considered as most accessible and desired location for both local and systemic drug delivery. The buccal method for medication delivery greatly helps in avoiding issues in the gastrointestinal environment, such as increased first-pass metabolism and medication degradation. Bucco-adhesive systems offer varieties of advantages such as convenience in administration and termination of therapy in case of emergency, higher patient compliance, better bioavailability, rapid absorption, etc. This current review highlights the bucco-adhesive drug delivery system, its advantages and limitations, mechanisms and theories of mucoadhesion, different bucco-adhesive dosage forms, and bioadhesive polymers. It also highlights the current status on mucoadhesive drug delivery methods for the buccal cavity or bucco-adhesive systems. Keywords: Bioadhesion, mucoadhesion, bucco-adhesive drug delivery system, oral mucosa, first-pass metabolism, bioadhesive polymers.

Embedding Procedure for Water Swollen Samples

1970 ◽  
Vol 28 ◽  
pp. 504-505
Author(s):  
Ann M. Thomas ◽  
Virginia Shemeley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Exchange ◽  
Structural Changes ◽  
Cross Linking ◽  
Ion Exchange Resins ◽  
Transmission Electron ◽  
First Pass ◽  
Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

Evidence for Early closure Attachment on First pass Reading Times in French

1997 ◽  
Vol 50 (2) ◽  
pp. 421-438 ◽  
Author(s):  
Daniel Zagar ◽  
Joel Pynte ◽  
Sylvie Rativeau
Keyword(s):  
First Pass ◽  
Early Closure

Therapie mit Opioiden bei Patienten mit Leberzirrhose

2020 ◽  
Vol 77 (1) ◽  
pp. 14-19
Author(s):  
Stephan Krähenbühl
Keyword(s):  
First Pass

Zusammenfassung. Für die Dosisangleichung bei Patienten mit Leberzirrhose gibt es keinen verlässlichen endogenen Parameter, der die metabolische Aktivität und das Ausmass der portacavalen Shunts repräsentiert. Die Angleichung muss deshalb unter Beachtung der pharmakokinetischen Eigenschaften der verabreichten Arzneistoffe erfolgen. Bei Arzneistoffen mit einem starken Abbau während der ersten Passage durch die Leber (first-pass Effekt) muss nach oraler Verabreichung mit einer Zunahme der Bioverfügbarkeit und verminderter Clearance gerechnet werden. Nach topischer, buccaler oder parenteraler Applikation spielt nur der Effekt auf die Clearance eine Rolle. Für Arzneistoffe mit einer hohen Bioverfügbarkeit (> 70 %) ist ebenfalls nur die hepatische Clearance entscheidend. In der Folge werden die in der Schweiz gebräuchlichen Opioide bezüglich pharmakokinetischer Eigenschaften und Konsequenzen bezüglich Dosisangleichung bei Patienten mit Leberzirrhose besprochen. Buprenorphin, Fentanyl, Hydromorphon, Morphin, Naloxon und Tapentadol sind Arzneistoffe mit einem hohen first-pass Effekt, währenddem Methadon, Oxycodon und Tramadol eine Bioverfügbarkeit von > 70 % aufweisen.

Einfluss der Gadofosveset-Injektionsgeschwindigkeit auf die Bildqualität der First-Pass MRA

2009 ◽  
Vol 181 (S 01) ◽  
Author(s):  
HJ Michaely ◽  
UI Attenberger ◽  
C Fink ◽  
O Dietrich ◽  
SO Schoenberg
Keyword(s):  
First Pass

Demonstration and Quantitation of Pharmacological Inhibition of Pulmonary Uptake of N-lsopropyl-123l-p-lodoamphetamine by Propranolol

1989 ◽  
Vol 28 (03) ◽  
pp. 100-104 ◽  
Author(s):  
S. F. Akber
Keyword(s):  
Binding Sites ◽  
Bolus Injection ◽  
Cell Function ◽  
Lung Pathology ◽  
Lung Uptake ◽  
Pharmacological Inhibition ◽  
Sensitive Index ◽  
Pulmonary Uptake ◽  
First Pass

The first-pass pulmonary extraction values of N-lsopropyl-123l-p-lodoamphetamine (123I-IMP) in pretreated dogs decreases from 90 to 62% as the amount of propranolol increases from 0 to 20 mg. The first-pass pulmonary extraction values of 123I-IMP in dogs with a simultaneous bolus injection of propranolol decreases from 90 to 62% as the amount of propranolol increases from 0 to 10 mg. The pulmonary extraction of 123I-IMP with a simultaneous bolus injection of ketamine and 123I-IMP decreases from 90 to 64% as the ketamine dose increases from 0 to 100 mg. These results suggest that the pulmonary uptake of 123I-IMP may be at least partially mediated by receptors. They also indicate that endothelial metabolic cell function may be a useful index of early lung pathology. Furthermore, studies of the degree of lung uptake may be a sensitive index of pathologic states in which alterations of amine binding sites have occurred.

Dipyridamole Inhibits Platelet Aggregation in Whole Blood

1983 ◽  
Vol 50 (04) ◽  
pp. 852-856 ◽  
Author(s):  
P Gresele ◽  
C Zoja ◽  
H Deckmyn ◽  
J Arnout ◽  
J Vermylen ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Significant Negative Correlation ◽  
Significant Inhibition ◽  
Oral Drug ◽  
Human Blood Samples ◽  
Induced Aggregation

SummaryDipyridamole possesses antithrombotic properties in the animal and in man but it does not inhibit platelet aggregation in plasma. We evaluated the effect of dipyridamole ex vivo and in vitro on platelet aggregation induced by collagen and adenosine- 5’-diphosphate (ADP) in human whole blood with an impedance aggregometer. Two hundred mg dipyridamole induced a significant inhibition of both ADP- and collagen-induced aggregation in human blood samples taken 2 hr after oral drug intake. Administration of the drug for four days, 400 mg/day, further increased the antiplatelet effect. A significant negative correlation was found between collagen-induced platelet aggregation in whole blood and dipyridamole levels in plasma (p <0.001). A statistically significant inhibition of both collagen (p <0.0025) and ADP-induced (p <0.005) platelet aggregation was also obtained by incubating whole blood in vitro for 2 min at 37° C with dipyridamole (3.9 μM). No such effects were seen in platelet-rich plasma, even after enrichment with leukocytes. Low-dose adenosine enhanced in vitro inhibition in whole blood.Our results demonstrate that dipyridamole impedes platelet aggregation in whole blood by an interaction with red blood cells, probably involving adenosine.

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