Drug implantation

Ultrasound Assists Drug Implants. Plastic materials infused with drugs are used for a number of purposes where drugs are gradually diffused into the bloodstream. Such implants are used for contraceptions and various chemotherapies. The effects of exposure to ultrasound of biodegradable implant materials have been studied at several teaching hospitals with interesting results. 

Zero-order absorption processes apply to iron, to depot i.m. formulations and to drug implants, e.g. antipsychotics and sex hormones. 

Other areas of technology where the transport of small molecules through polymers plays a key role include foams (where small molecules are used as blowing agents for foam expansion [9-11] and any gas trapped in the cells of a closed-cell foam affects key properties such as the thermal conductivity [12]), plasticization [13,14], removal of process solvents, residual monomers or other impurities by techniques such as supercritical fluid extraction [15,16], biosensors, drug implants, and polymer electrolytes (where the penetrants are ionic). 

Historically, a somewhat dated study by BCC Business Communication Company Inc. (2004) indicated that the total orthopaedic drug, implant and device market was expected to reach US 44 billion by the end of 2004. Rising at an average annual growth rate (AAGR) of 11%, the market was expected to reach US ... 

BCC Business Communication Company Inc. (2004) Orthopedic Drugs, Implants and Devices. Report code PHM040A, Market Research, October 2004. 

DNLM 1. Drug Delivery Systems. 2. Biocompatible Materials. 3. Drug Implants. 4. Pharmacokinetics. 5. Polymers. WB 354 S179d 2001]... 

Farmed animals tend to be subjected to compounds that can be classified more easily as drugs. In some cases, animals may encounter compounds in nature that have considerable limitations in inclusion in the diets of farmed animals. An example is the inclusion of zearalenone (Figure 1) and its derivatives in animal diets these have anabolic and oestrogenic properties " and are permitted to be used in some areas of the world but are prohibited from use in others, such as European Union countries. Thus this compound and its reduced isomers (zearalenols, zeranols) improve growth rates in animals but can cause reproductive problems, especially in pigs. Ralgro, which is a commercially prepared derivative of zearalenone, is used as an ear implant in beef cattle as a growth promoter in... 

Hormonal contraceptives belong to the most widely prescribed and most efficacious drugs that have a profound impact on western societies since their inauguration in the 1960s. In women, oral hormonal contraceptives are used to prevent fertilization or implantation in cases of unplanned pregnancies. Apart from these primary objectives, there are significant additional medical benefits contributing to a substantial improvement of reproductive health in women. 

Dru may be applied to the skin and mucous membranes using several routes topically (on the outer layers of skin), transdermally through a patch on which the drug has been implanted, or inhaled through the membranes of the upper respiratory tract. 

Goserelin (Zoladex), a hormonal antineoplastic drug used to treat breast cancer, is administered subcutaneously in an unusual way. The drag is contained in a dry pellet that is implanted in the soft tissue of the abdomen, where it is gradually absorbed during a period of 1 to 3 months. After a local anesthetic, such as lido-caine, is administered, a large needle (usually 16 gauge) is used to insert the pellet. 

Je a means of delivering drugs over a at a controlled rate inside the bodv. Sub- skin) implants are used to provide appro-loactive medications, birth-control drugs,... 

TOF-SIMS has important potentials in many areas of life science, in fundamental and applied research as well as in product development and control. This holds for the characterization of biological cells and tissues, of sensor and microplate arrays, of drug delivery systems, of implants, etc. In all these areas, relevant surfaces feature a very complex composition and structure, requiring the parallel detect ion of many different molecular species as well as metal and other elements, with high sensitivity and spatial resolution requirements, which are exactly met by TOF-SIMS. 

The earlier work of Miller (35), Outright (37), and Brady (5) on nonmedicated implants provided an excellent basis for further studies on specific controlled release formulations such as the determination of the biodegradation rates of lactide/glycolide drug-loaded microspheres (38). Those studies were done with l c-iabeled polymers produced from DL-lactic acid and glycolide. The final formulations tested in rats were microspheres loaded with H-labeled steroid and polymer as the matrix. The microspheres were administered intramuscularly and animals were serially sacrificed over a period of about a year. 

The earliest reports of controlled release steroids were those of Jackanicz (63), Yolles (64), Anderson (65), and Wise (66). Most of those early studies were based on poly[ (L+)-lactic acid). Implants and granular particles were fabricated with progesterone, norgestrel, and norethisterone. In vivo urinary excretion studies were conducted on [I Cjprogesterone beads (64). The reported results were somewhat questionable as only 20% of the original implanted drug could be accounted for. 

Recently, Tsakala et al. (90) formulated pyrimethamine systems based on several lactide/glycolide polymers. These studies were conducted with both microspheres (solvent evaporation process) and implants (melt extrusion process). In vitro studies indicated that pyrimethamine-loaded implants exhibited apparent zero-order release kinetics in aqueous buffer whereas the microspheres showed an initial high burst and considerably more rapid drug release. In vivo studies in berghi infected mice confirmed that the microspheres did not have adequate duration of release for practical application. However, the implants offer promise for future clinical work as more than 3 months protection was observed in animals. 

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