Release rates of levonorgestrel from Silastic capsules, homogeneous rods and covered rods in humans

Contraception
D N RobertsonJ Dinh

Abstract

Three forms of subdermal implants containing levonorgestrel are described. These are: capsules, in which the powdered drug is sealed inside of lengths of Medical Grade Silastic tubing; homogeneous rods, in which the drug is uniformly dispersed in Silastic 382 Medical Grade Elastomer; and covered rods, in which a core rod of drug and filler-free polydimethylsiloxane polymer (50:50, Wt:Wt) are sealed inside thin-walled Silastic tubing. Long-term in vivo release rates from human subjects are presented; 6.5 years for capsules, 3.6 years for homogeneous rods and 4 years for covered rods. Sets of six capsules release a decreasing amount of drug through the first few hundred days in situ and after 500 days a fairly constant rate of about 35 micrograms per day is released (2 micrograms/cm). Homogeneous rods deliver a continuously declining amount of drug during the entire time studied. In the first 100 days the release averages 136 micrograms per day from a set of three 3-cm rods (15 micrograms/cm), gradually declining to 30 micrograms per day (3.3 micrograms/cm) from day 800 to day 1300. The covered rods deliver at a constant rate of 17.5 micrograms per day for a 3-cm rod (5.83 micrograms/cm) through 4 years.

References

Oct 1, 1978·Plastic and Reconstructive Surgery·L M VistnesJ Kosek
Jan 1, 1979·Annals of Plastic Surgery·R Gayou, R Rudolph
Oct 1, 1978·Contraception·H A NashL E Atkinson
Jun 1, 1973·Plastic and Reconstructive Surgery·H G Thomson

❮ Previous
Next ❯

Citations

Dec 1, 1992·Advances in Contraception : the Official Journal of the Society for the Advancement of Contraception·V BracheL Cochon
Aug 1, 1996·Contraception·A BiswasO A Viegas
Jan 28, 2004·Journal of Controlled Release : Official Journal of the Controlled Release Society·Hiroo MaedaYuji Kurosaki
Feb 28, 2002·Contraception·Horacio B Croxatt
Sep 24, 1999·Pediatric Clinics of North America·Z Harel, B Cromer
Oct 26, 2002·Journal of Controlled Release : Official Journal of the Controlled Release Society·Miho MaedaToshiki Yoshimine
May 28, 2003·Journal of Controlled Release : Official Journal of the Controlled Release Society·Hiroo MaedaYuji Kurosaki
Jul 25, 2003·International Journal of Pharmaceutics·H MaedaA Sano
Aug 1, 1991·The Australian & New Zealand Journal of Obstetrics & Gynaecology·M Cooper
Mar 10, 2000·Journal of Controlled Release : Official Journal of the Controlled Release Society·M KajiharaY Urabe
Feb 1, 1988·American Journal of Obstetrics and Gynecology·J A NiskerJ T Nunez-Troconis
May 1, 1989·American Journal of Obstetrics and Gynecology·D Shoupe, D R Mishell
Mar 24, 2016·Contraception·Ganesh CheralaFrank Z Stanczyk
Aug 1, 1986·Contraception·S E OlssonE Johansson
Jul 1, 1990·Contraception·S E OlssonE Johansson
Dec 24, 1997·Pediatric Clinics of North America·S Lappa, A B Moscicki

❮ 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.