Release system

A prolonged action/controlled release system developed to deUver levonorgestrel for contraceptive therapy involves implantation of a set of flexible closed capsules made of demethylsiloxane—methylvinyl—sdoxane copolymer (see Contraceptives). Each capsule measures 2.4 mm in diameter and 34 mm in length. A set of six such capsules is surgically implanted beneath the skin of the upper arm. These capsules are intended to be removed by the end of the fifth year after implantation. 

Beyond these indirect costs, there are future costs associated with new or more stringent variations of existing environmental legislation. We also need to recognize that all operations, especially those within complex industry sectors like petrochemicals, carry liabilities and exposures to potential catastrophic releases. Systems do fail for a variety of reasons, leading to unplarmed and sometimes innocent mistakes, that may result in third-party exposures for environmental damages or health risk exposures. These costs are related to legal fees, loss in consumer confidence, and subsequent losses in market shares for the products a company sells, as well as the clean-up associated with the spill or release. 

Sizing of Flare System and Other Closed Release Systems... 

The factors affecting the sizing of a closed release system to the flare are described below. The same principles apply to the sizing of other closed release systems e.g., PR valve releases which are manifolded into an atmospheric vent. 

Design and Installation of Pressure-Release Systems in References Part 1 -Design , API Recommended Practice 520, 4 ed., American Petroleum Institute, Wasliington DC, 1976,... 

FIGURE 4 Controlled release systems based on lactide/glycolide polymers with duration of action of a few days to 1 year. 

Hsieh, D. S. T., Controlled Release Systems Fabrication Technology, Vol. 2, CRC Press, Boca Raton, 1988. 

Lewis, D. H., Tice, T. R., and Beck, L. R., Overview of controlled release systems for male contraception, in Male Contraception Advances and Future Prospects (G. I. Zatuchni, ed.). Harper and Row, Philadelphia, 1986, pp. 336-345. 

M., Pyrimethamine sustained release systems based on bioresorbable polyesters for chemoprophylaxis of rodent malaria,... 

Bovine growth hormone, a difficult protein for which to develop controlled release systems due to its propensity toward self-aggregation and inactivation, has successfully been incorporated into polyanhydride matrices (18). The growth hormone was colyophilized with sucrose, dry-mixed with finely powdered polyanhydride, and then compression molded into 1.4-cm-diaraeter wafers, 1 mm thick. As is shown in Fig. 15, release of bovine growth hormone was well controlled over a prolonged period of time. The assay for bovine... 

Strobel, J. D., Laughlin, T. J., Austroy, F., Lilly, M. B., Perkins, B. H., and Dunn, R. L., Controlled-release systems for anticancer agents, Toronto Controlled Release Society, Proc. 14th Int. Symp. Control. Rel. Bioact. Materials. 261-262, 1987. 

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