Steroid delivery systems for contraception.

B B Pharriss; V A Place; L Sendelbeck; E Schmitt

Home/Archive/PubMed

PubMed · 957363

Steroid delivery systems for contraception.

B B Pharriss·V A Place·L Sendelbeck·E Schmitt

View original source ↗Export metadata ↓

Abstract

Scientific disciplines not normally associated with pharmaceutical development have been employed to enhance the effectiveness and attractiveness of two approaches to steroidal contraception. The use of a bioerodible polymeric carrier for predictable systemic steroidal administration has removed the largest hurdle to the development of a subcutaneous contraceptive implant. A polymeric progesterone delivery system has provided a method for localizing hormonal contraception in the uterine cavity. Extensions of these technologies may provide two useful tools in limiting fertility in an already overcrowded world.

Explore related subjects

Biocompatible Materials Contraception Contraceptive Devices, Female Drug Implants Female Humans Intrauterine Devices Progesterone Progesterone Congeners Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

B B Pharriss, V A Place, L Sendelbeck, E Schmitt. 1976. Steroid delivery systems for contraception.. https://pubmed.ncbi.nlm.nih.gov/957363/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Development of a 3D cell culture system for investigating cell interactions with electrospun fibers.

There are many variables to be considered in studying how cells interact with 3D scaffolds used in tissue engineering. In this study we investigated the influence of the fiber diameter and interfiber spaces of 3D electrospun fiber scaffolds on the behavior of human dermal fibroblasts. Fibers of two dissimilar model materials, polystyrene and poly-L-lactic acid, with a broad range of diameters were constructed in a specifically developed 3D cell culture system. When fibroblasts were introduced to freestanding fibers, and encouraged to "walk the plank," a minimum fiber diameter of 10 microm was observed for cell adhesion and migration, irrespective of fiber material chemistry. A distance between fibers of up to 200 microm was also observed to be the maximum gap that could be bridged by cell aggregates--a behavior not seen in conventional 2D culture. This approach has identified some basic micro-architectural parameters for electrospun scaffold design and some key differences in fibroblast growth in 3D. We suggest the findings will be of value for optimizing the integration of cells in these scaffolds for skin tissue engineering.

Biocompatible Materials↗

PubMed2007

Improved catalytic properties of immobilized lipases by the presence of very low concentrations of detergents in the reaction medium.

The addition of a very small concentration of a detergent (in many instances under the critical micellar concentration (cmc)) has been found to greatly increase the activity of immobilized lipases, using those from Pseudomonas fluorescens (PFL) and Candida antarctica (isoform B) as model enzymes. However, the detergents may also have a negative effect on enzyme activity; in fact, for all enzyme preparations and substrates the activity/detergent concentration curve reached a maximum value and started to decrease, in many instances even under the initial value. The concentration and nature of the detergent (SDS, CTAB, Triton X-100, or X-45) that permitted the maximum hyperactivation was different depending on the substrate. The best hyperactivation values promoted by the presence of detergent were over a 20-fold factor. The presence of detergents permitted the inhibition of lipases by irreversible covalent inhibitors (e.g., 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride) (AEBSF) while the enzyme, in the absence of detergent, is not inhibited by these irreversible inhibitors. This suggested that the main effect of the detergents is to shift the conformational equilibrium of lipases toward the open form. Moreover, the presence of detergents also permitted to improve the enantioselectivity exhibited by the immobilized lipases in some cases. For example, the enantioselectivity of PFL-glyoxyl agarose increased from 40 to more than 100 in the hydrolysis of (+/-)-2-hydroxy-4-phenylbutyric acid ethyl ester by using 0.1% CTAB.

Biocompatible Materials↗

PubMed2007

Development of wollastonite-poly(ethylmethacrylate co-vinylpyrrolidone) based materials for multifunctional devices.

The manufacturing of a composite made of a synthetic bioactive ceramic, pseudowollastonite (psW), and a bioresorbable copolymer ethylmethacrylate-vinylpyrrolidone (EMA/VP) is presented in this article. psW porous blocks were produced by dipping an open porous polyurethane foam in a psW containing slurry. A 40/60 wt % EMA/VP monomers mixture was poured on the blocks, and free radical polymerization initiated by azobis(isobutyronitrile) at 50 degrees C. Disks of 1 mm height were obtained by cutting the composite with a diamond saw, and bioresorption and bioactivity of the specimens were tested by immersion of the disks into SBF. A ceramic/polymer weight ratio of 72/28, greater than the usually achievable ratio by polymeric solidification of slurries of monomers charged with a powdered solid component, has been obtained. The system is bioactive and does not change the pH of the medium during the degradation test.

Biocompatible Materials↗