Silastic

Silastic Compounding System, Dow Corning, Midland, Mich., 1977. 

D. M. Smith and co-workers, A Preliminary Toxicological Study of Silastic 386 Catalyst, Report LA-7367-MS, Los Alamos Scientific Laboratory, Los Alamos, N.M., une 1978. 

Implanted Contraceptives. Controlled release of contraceptive progestins also can be accompHshed by incorporating the dmg into an implantable cylinder or rod. The best known implant is Norplant, developed by the Population Council. Norplant is composed of six matchlike silastic cylinders with the progestogen levonorgestrel (11) incorporated on the inside of each cylinder. After implantation under the skin, the product can provide effective contraception for a period of five years (43,44). Since silastic is not biodegradable, the implant can be removed from a patient at any time. 

While the effective life of Norplant I is at least five years, most of the users have the implants removed at an earlier time. Norplant II was developed to have a shorter life-span, and is composed of only two rods. Levonorgestrel is dispersed in the silastic matrix which is then inserted into a thin silastic tubing. This product has an effective life-span of two to three years (36). Because it is composed of only two rods, Norplant II also is easier to implant and remove. 

Silastic LS 420, possessing approximately Q.6%-0.9% pendant vinyl groups, was blended with Kynar 7201, a vinylidene fluoride copolymer with tetrafluoroethylene (Atochem), in the presence of triallylisocyanurate (TAIC) and DAP containing a small amount of benzoyl peroxide in the DAP fraction. 

Stannous octoate has the advantage of having been used to prepare polymers (Silastic, Capronor) for which substantial toxicological data are now available (6,48). Stannous octoate-initiated polymerization has been used to prepare copolymers of e-caprolactone with other lactones, including diglycolide, dilactide, 6-valerolactone, e-decalactone, and other alkyl-substituted e-caprolactones. Conducting... 

Baboons were surgically prepared with chronically indwelling silastic catheters implanted in either femoral or jugular veins under pentobarbital or halothane anesthesia using methods described in detail by Lukas et al. 

Silaste M, Rantala M, Alftham G, Aro A and Kessaniemi Y. 2003. Plasma homocysteine concentration is decreased by dietary intervention. Br J Nutr 89 295-301. 

In an effort to optimize the solvent-containing passive sampler design, Zabik (1988) and Huckins (1988) evaluated the organic contaminant permeability and solvent compatibility of several candidate nonporous polymeric membranes (Huckins et al., 2002a). The membranes included LDPE, polypropylene (PP), polyvinyl chloride, polyacetate, and silicone, specifically medical grade silicone (silastic). Solvents used were hexane, ethyl acetate, dichloromethane, isooctane, etc. With the exception of silastic, membranes were <120- um thick. Because silicone has the greatest free volume of all the nonporous polymers, thicker membranes were used. Although there are a number of definitions of polymer free volume based on various mathematical treatments of the diffusion process, free volume can be viewed as the free space within the polymer matrix available for solute diffusion. 

Petty and Orazio (1996) developed an interesting variation in SPMD liquid phases. The approach consisted of both LDPE and silastic ffibes containing silicone fluid (50 cSt or 3200 MW) with 3% by weight PX-21 activated carbon. The presence of the activated carbon enhanced retention of planar molecules such as PAHs and the silicone fluid remains liquid at temperatures below freezing. However, the partition coefficients of HOCs for this type of silicone fluid are much lower than for triolein. 

Huckins, J.N. and Petty, J.D.1994a, Use of medical-grade silicone or silastic mbing alone as apassive sampler medium. USGS, Columbia Environmental Research Center, Colrrmbia, MO Unpublished work. 

Males also depend on testosterone for olfactory performance. If in hamsters testosterone is converted to estrogen by subcutaneous silastic implants of the aromatase inhibitor l,4,6-androstatriene-3,17-dione, their sexual sniffing decreases. They sniff less toward novel females and no longer discriminate between males and females (Steel and Hutchinson, 1987). Castration affects odor detection performance in male rats (Doty and Ferguson-Segall 1989). 

Levonorgestrel implants consist of 6 Silastic capsules each capsule is 2.4 mm in diameter and 34 mm in length and contains 36 mg levonorgestrel. Total administered (implanted) dose is 216 mg. Perform implantation of all 6 capsules during the first 7 days of menses onset. Insertion is subdermal in the mid-portion of the upper arm (see literature included with the product). 

Erlund, L, Silaste, M.L., Alfthan, G., Rantala, M., Kesaniemi, Y.A., and Aro, A., Plasma concentrations of the flavonoids hesperetin, naringenin and quercetin in human subjects following their habitual diets, and diets high or low in fruit and vegetables, Eur. J. Clin. Nutr., 56, 891, 2002. 

Matrix polymer PDMS (Silastic 382 Medical Grade Elastomer, Dow Coming Corp., Midland, MI) ... 

Drug and excipients were sieved to obtain a particle size between 45 and 90 pm. The model dmg Gly-Tyr and excipient were thoroughly dispersed in Silastic 382 plus curing agent. Dispersions were quickly transferred to a mould. After curing (24 h, 40°C), a sheet of 1.5 mm thickness was... 

D.N.Robertson, I.Sivin, H.A.Nash, J.Braun and J.Dinh, Release rates of levonorgestrel from silastic capsules, homogeneous rods and covered rods in humans, Contraception, 27,483 195 (1983). 

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