USES IN MEDICINE

Uses in Medicine The application of synthetic polymers in medicine is relatively new, causing a real revolution. It covers medical aids, accessories. 

Other uses are found in plastic surgery, artificial skin and blood substitutes. An unique field is found in membranes for dialysis. PE, mostly linear (including UHMW), serves in many implants or in artificial joints. PVC is the most useful polymer in medicine, in plasticized form for flexible tubing, dialysis and infusion systems. PP is offered for disposible injections and, together with ethylene (copolymer), in blood bags. PS serves as a substitute for glass in tubes, bottles and petri dishes, and as the copolymers SAN or ABS in a wide host of uses. Polyester (PET) is used in sewing threads or nets in prostheses. PC is used (as a replacement for cellophane) in membranes for dialysis as well as in blood pumps and other systems. 

Another engineering polymer, polysulfone, presents excellent resistance to sterilization while it is also well accepted by the human body and thus is adequate for implanted systems. 

PMMA is mostly utilized for vision—both hard and soft lenses (usually as copolymers), implanted lenses, and artificial eyes. 

Silicone is widely used in artificial limbs and in fixing defects of the body, membranes, implanted capsules for slow-release medications, artificial skin and in insulation of implanted electrical devices. 

---

Mercury compounds (for example mercury(II) chloride) are used in medicine because of their antiseptic character. The artificial red mercury(Il) sulphide is the artist s vermilion . Mercury(II) sulphate is a catalyst in the manufacture of ethanal from ethyne ... 

Chloroform was formerly used in medicine as an anaesthetic. One disadvantage for this purpose is the ready oxidation which chloroform undergoes on exposure to light and air, generating the poisonous phosgene, or carbonyl chloride, COCU- This is counteracted by storing the liquid in dark amber-... 

Acetylsalicylic acid is largely used in medicine as an analgesic (t.e., for removing pain) and as an antipyretic (i.e., for reducing the body temperature). 

It is also used as a reducing agent in the production of pure uranium and other metals from their salts. The hydroxide (milk of magnesia), chloride, sulfate (Epsom salts), and citrate are used in medicine. Dead-burned magnesite is employed for refractory purposes such as brick and liners in furnaces and converters. 

Iodine compounds are important in organic chemistry and very useful in medicine. Iodides, and thyroxine which contains iodine, are used internally in medicine, and as a solution of KI and iodine in alcohol is used for external wounds. Potassium iodide finds use in photography. The deep blue color with starch solution is characteristic of the free element. 

Antibiotics are toxic water-solubie compounds produced by molds or bacteria which inhibit the growth of other microorganisms. For an antibiotic to be useful in medicine it should have a high order of selective toxicity to microorganisms which are pathogenic to man. Al-... 

Many artificial (likely radioactive) isotopes can be created through nuclear reactions. Radioactive isotopes of iodine are used in medicine, while isotopes of plutonium are used in making atomic bombs. In many analytical applications, the ratio of occurrence of the isotopes is important. For example, it may be important to know the exact ratio of the abundances (relative amounts) of the isotopes 1, 2, and 3 in hydrogen. Such knowledge can be obtained through a mass spectrometric measurement of the isotope abundance ratio. 

Industrial antimicrobial agents are chemicals used to prevent the adverse consequences of microbiological activity in processes and products. Some are unique to this segment and others are drawn from the antimicrobial agents used in medicine, agriculture, and sanitary appHcations. Industrial antimicrobials are selected where process or stricdy physical conditions, such as irradiation or heat, are impractical or ineffective in controlling microbiological activity. 

Uses and Economic Aspects. Magnesium bromide is used in medicine as a sedative in treatment of nervous disorders, in electrolyte paste for magnesium dry cells, and as a reagent in organic synthesis reactions. The price of magnesium bromide hexahydrate in January 1995 was 5.51/kg (33). 

Some elements found in body tissues have no apparent physiological role, but have not been shown to be toxic. Examples are mbidium, strontium, titanium, niobium, germanium, and lanthanum. Other elements are toxic when found in greater than trace amounts, and sometimes in trace amounts. These latter elements include arsenic, mercury, lead, cadmium, silver, zirconium, beryUium, and thallium. Numerous other elements are used in medicine in nonnutrient roles. These include lithium, bismuth, antimony, bromine, platinum, and gold (Eig. 1). The interactions of mineral nutrients with... 

Fig. 1. Periodic Table showing elements of importance in biological systems principal element of bioorganic compounds essential mineral nutrients for humans and other animals 1 essential mineral nutrient for animals, probably for humans M present in body, not known to be a nutrient or toxic element M element used in medicine element generally poisonous and present in body, possibly toxic.

Estimated worldwide sales are given in Table 1 for the aminoglycoside derivatives most commonly used in medicine. Although amikacin has somewhat higher sales, gentamicin is by far the most widely used in terms of number of courses of treatment. 

Aledicine. A wide variety of alkaloids (qv) contain the quinoline ring system this fact accounts, in large measure, for the extensive synthetic research reported (107). In addition to the naturally occurring compounds, a large number of synthetic quinolines, eg, (22) and (23), have been prepared and studied for use in medicine. Table 3 presents selected examples. 

Selenium plays a dual role in a living organism, depending on the compound and the amount adsorbed. Controlled small doses of some compounds are used in medicine and as diet supplements, for example, ca 0.1 ppm of diet dry matter for Hvestock (see Feed additives Mineral nutrients). Larger amounts can be toxic. 

Medicinal Preparations. Silver nitrate is used in medicine in the form of a stick, usually containing 1—3% silver chloride, or in solutions of varying concentrations. Uses of silver in medicine as of the 1990s are much reduced from earlier in the twentieth century because of the availabiHty of a... 

Most of the thiamine sold worldwide is used for dietary supplements. Primary market areas include the following appHcations addition to feed formulations, eg, poultry, pigs, catde, and fish (see Feeds and feed additives) fortification of refined foods, eg, flours, rice, and cereal products and incorporation into multivitamins. Small amounts are used in medicine to treat deficiency diseases and other conditions, in agriculture as an additive to ferti1i2ers (qv), and in foods as flavorings. Generally for dry formulations, the less soluble, nonhygroscopic nitrate is preferred. Only the hydrochloride can be used for intravenous purposes. Coated thiamine is used where flavor is a factor. 

The final reduction product of pyrazine, piperazine (89), is a stable compound which behaves as a typical diamine. It has found extensive use in medicinal chemistry as a linking agent and as a medicine in its own right for the treatment of helminths both in human and veterinary medicine. 

The applications sections of monograph chapters provide access to important compounds used in medicine or industry, to industrially important sources of compounds, and to key natural products. 

Benzoyl-2,3-dihydro-lH-pyrrolizine-l-cai boxylic acid (ketorolac, L ) and 2-(3-benzoyl-phenyl)propionic acid (ketoprofen, L ) ai e biologically activ ligands used in medicine as non-steroidal anti-inflammatory dmgs. 

Energy-dispersive X-ray spectroscopy has been used for quality control and test analysis in many industries including computers, semiconductors, metals, cement, paper, and polymers. EDS has been used in medicine in the analysis of blood, tis-... 

The fluids have also found a number of uses in medicine. Barrier creams based on silicone fluids have been found to be particularly useful against the cutting oils in metal machinery processes which are common industrial irritants. The serious and often fatal frothy bloat suffered by ruminants can be countered by the use of small quantities of silicone fluid acting as an antifoam. 

Another important ether is vinyl ether, a colorless liquid with the characteristic ether odor. Its molecular formula is CjHjOCjHj. Vinyl ether has a flash point of -22°F and an ignition temperature of b80°F. It is highly toxic by inhalation and is used in medicine and in the polymerization of certain plastics. 

The common hemlock, Conium maculatum, contain five alkaloids. Power and Tutin found a similar mixture in fool s parsley, and a volatile alkaloid resembling coniine i.s stated to occur in certain aroids. According to Svagr, water hemlock Cicuta virosa) owes its poisonous properties to toxin and not to cicutine, a name sometimes used as a synonym for coniine. The toxic properties of hemlock juice have been known ftom very early times thus it was the chief ingredient in the poison administered to criminals by the Greeks. The leaves and the unripe fruits are the parts used in medicine. The following are the names and formulae of the alkaloids —... 

B. HAUCI4, separates as an oil, but solidifies on standing and may be recrystallised from water containing hydrochloric acid. The crystals melt at 137-9° or below 100° when heated under water. This salt and the picrate, rectangular plates, m.p. 175-6°, are well adapted for the identification of the alkaloid. The methobromide, m.p. 223-5°, and the inethonitrate, m.p. 166-8°, are now both used in medicine. 

---