Biomaterial Database

The bioavailability and disposition of tiodazosin levulinate in beagle dogs with a comparison to prazosin hydrochloride. 1983

R A Baughman, and B A Mico, and L Z Benet

Tiodazosin is a recently developed compound that is currently undergoing investigation for use in hypertension. It is structurally and pharmacologically similar to prazosin, the prototype of the aminoquinazoline class of vasodilators. Lacking an intravenous dosage form for use in human subjects, our study concentrated on the determination of the bioavailability and disposition parameters of tiodazosin in dogs, with a comparison to those parameters for prazosin, obtained from previous work in our laboratory. Tiodazosin was administered to five male beagle dogs at a dose of 1 mg/kg both intravenously and as an oral solution. Plasma and whole blood samples were taken serially over 24 hr and analyzed with a new specific and sensitive HPLC assay. The half-life of tiodazosin was significantly shorter than that of prazosin. The tiodazosin-calculated bioavailability was 3-fold less than predicted, whereas prazosin-calculated bioavailability was the same as predicted. Assumptions necessary to predict the bioavailability of compounds cleared by the hepatic route appear to be incorrect for tiodazosin. Possible mechanisms for the unpredictable low tiodazosin bioavailability in dogs are presented.

UI	MeSH Term	Description	Entries
D007263	Infusions, Parenteral	The administration of liquid medication, nutrient, or other fluid through some other route than the alimentary canal, usually over minutes or hours, either by gravity flow or often by infusion pumping.	Intra-Abdominal Infusions,Intraperitoneal Infusions,Parenteral Infusions,Peritoneal Infusions,Infusion, Intra-Abdominal,Infusion, Intraperitoneal,Infusion, Parenteral,Infusion, Peritoneal,Infusions, Intra-Abdominal,Infusions, Intraperitoneal,Infusions, Peritoneal,Intra Abdominal Infusions,Intra-Abdominal Infusion,Intraperitoneal Infusion,Parenteral Infusion,Peritoneal Infusion
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D011224	Prazosin	A selective adrenergic alpha-1 antagonist used in the treatment of HEART FAILURE; HYPERTENSION; PHEOCHROMOCYTOMA; RAYNAUD DISEASE; PROSTATIC HYPERTROPHY; and URINARY RETENTION.	Furazosin,Minipress,Pratsiol,Prazosin HCL,Prazosin Hydrochloride,HCL, Prazosin,Hydrochloride, Prazosin
D011799	Quinazolines	A group of aromatic heterocyclic compounds that contain a bicyclic structure with two fused six-membered aromatic rings, a benzene ring and a pyrimidine ring.	Quinazoline
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D006207	Half-Life	The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.	Halflife,Half Life,Half-Lifes,Halflifes
D000284	Administration, Oral	The giving of drugs, chemicals, or other substances by mouth.	Drug Administration, Oral,Administration, Oral Drug,Oral Administration,Oral Drug Administration,Administrations, Oral,Administrations, Oral Drug,Drug Administrations, Oral,Oral Administrations,Oral Drug Administrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001682	Biological Availability	The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.	Availability Equivalency,Bioavailability,Physiologic Availability,Availability, Biologic,Availability, Biological,Availability, Physiologic,Biologic Availability,Availabilities, Biologic,Availabilities, Biological,Availabilities, Physiologic,Availability Equivalencies,Bioavailabilities,Biologic Availabilities,Biological Availabilities,Equivalencies, Availability,Equivalency, Availability,Physiologic Availabilities