PMID: 8946670Dec 1, 1996Paper

Evidence for saturable incorporation of methadone into rat hair: relationships among oral dose, plasma concentration, and hair content

Therapeutic Drug Monitoring
S J Green, J F Wilson

Abstract

Six groups of six male Wistar rats were administered methadone in their drinking water over the concentration range 0-0.25 mg/ml. Hair and trunk blood samples were collected after a 6-week period of drug administration. Immunoreactive methadone was measured by radioimmunoassay and methadone and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidene (EDDP), by gas chromatography in plasma and alkali digests of hair. Plasma methadone concentration increased with increasing oral dose. The mean hair concentration of methadone increased to a maximum of 5.1 ng/mg at a drinking water concentration of 0.1 mg/ml corresponding to a plasma level of 14.0 ng/ml. No further significant rise in hair content was seen with higher drinking water concentrations despite a continuing increase in oral drug intake and in plasma methadone concentration. EDDP was not detected in plasma but was present at > 2 ng/mg in 25% of hair samples. The mean EDDP concentration in hair peaked at 3.2 ng/mg at the lowest dose level of methadone administered. The data suggest that methadone is incorporated into rat hair via a capacity-limited process that becomes saturated at plasma levels of some 14 ng/ml. Competition for uptake into hair between met...Continue Reading

References

Jan 1, 1992·International Journal of Legal Medicine·P KintzP Mangin
Jan 1, 1992·The International Journal of the Addictions·S MaguraD S Lipton
Oct 1, 1974·The British Journal of Dermatology·W H HarrisonL M Solomon
Jan 1, 1994·Journal of Toxicology. Clinical Toxicology·R W ReidJ W Crayton
Dec 1, 1993·Forensic Science International : Synergy·D L Blank, D A Kidwell
Dec 1, 1993·Forensic Science International : Synergy·T Mieczkowski, R Newel
Aug 1, 1993·Clinical Pharmacokinetics·T Uematsu

❮ Previous
Next ❯

Citations

Nov 14, 2006·Forensic Science International : Synergy·Gisela SkoppDerik Hermann

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.