Vitamin therapeutic application

Vitamin E (alpha-tocopherol) is still perhaps the least understood of all the body s vitamins in terms of its biological actions. This is despite abundant experimentation and numerous clinical studies spanning over 60 years. In some respects, the paucity of information has fuelled a continuing interest in vitamin E, but this gap in established scientific knowledge has also generated many speculative biological roles and doubtful potential therapeutic applications. 

The medicinal chemistry of vitamins is fundamental not only to the therapeutics of nutritional problems but also to the understanding of the biochemical actions of other medicinal agents that directly or indirectly affect the metabolic functions of vitamins and coenzymes. Accordingly, this chapter includes a brief sununary of the basic biochemislry of vitamins, structure-activity relationships, physicochemical properties and some stability considerations, nutritional and therapeutic applications, and brief characterizations of repre.sentative pharmaceutical products. 

The editors concept of clinical chemistry, as stated in previous volumes of this serial publication, encompasses a wide field of subjects— from the mechanism of blood coagulation to the microbiological assay of vitamins, and from the significance of trace metals in health and disease to the therapeutic application of increased gas pressure. The natural history of clinical conditions and their comparison with normal controls share one common feature, namely, the central position of some species of molecules, be they small or large, all of them the natural subject of chemical research. Hence, practical methods develop, either manual or mechanized, the results of which become increasingly more useful for the clinician in diagnosis, therapy, and prognosis. 

The vitamin has also been routinely prescribed in cases of threatened abortion, thyroxidosis, achlorhydia, diarrhoea, prickly heat, rheumatic fever, rheumatic arthritis, and in cases of spinal injury to reduce urine acidity. The physiological basis of these therapeutic applications is not entirely clear except in the cases of achlorhydia and diarrhoea where there is a risk of anaemia caused by a reduction in the intestinal absorption of non-haem iron which is enhanced by vitamin C. 

Special credit is due to Marks and Nitowsky for their very critical and conservative conclusion regarding the therapeutic application of vitamin E. 

Since PHAs are isotactic, they can serve as a feedstock for enantiomeric compounds, which can be used in the synthesis of chiral chemicals such as antibiotics, vitamins, fragrances, and pheromones. Optically pure monomers may be obtained from PHAs by chemical hydrolysis at 80-160°C using a titanate catalyst (25) or by enzymatic hydrolysis using extracellular bacterial depolymerases. It is possible to synthesize the optically active monomers by using bacteria, which can make the polymer but lack the 3-hydroxyalkanaote polymerase (Fig. 3a) or possess a high activity of intracellular PHA depolymerase. Monomers such as 4HB have therapeutic applications as an intravenous anaesthetic, for the treatment of narcolepsy, alcohol, heroin, and nicotine addiction (26). 

In the present Chapter we will mainly focus on the beneficial effects light can make on human health and on its many therapeutic applications. In order to follow a historical timeline, we will start by discussing the only beneficial effect of UV radiation from sunlight on human health vitamin D synthesis. 

In addition to being necessary for all forms of life, biopolymers, especially enzymes (proteins), have found commercial applications in various analytical techniques (see Automated instrumentation, clinical chemistry Automated instrumentation, hemtatology Biopolymers, analytical techniques Biosensors Immunoassay) in synthetic processes (see Enzyme applications, industrial Enzyme applications in organic synthesis) and in prescribed therapies (see Enzyme applications, THERAPEUTICS IMMUNOTHERAPEUTIC AGENTS Vitamins). Other naturally occurring biopolymers having significant commercial importance are the cellulose (qv) derivatives, eg, cotton (qv) and wood (qv), which are complex polysaccharides. 

There are some well-described deficiency syndromes, the well-established therapeutic use of vitamin K antagonists as oral anticoagulants and the well-known positive effects of pantothenic acid on skin hydration/moisturization and wound healing, which apparently lacks scientific solid base. Apart from that there are not many studies available on the treatment of dermatological disorders with these vitamins, either systemically or topically. Even less is known about transdermal penetration, stability, and formulation dependencies of possible topical applications. 

Emulsions have been used for centuries for the oral administration of medical oils and vitamins and as dermatological vehicles. Recently, their application has been extended as drug carriers in the delivery and targeting of ophthalmic drags. An indomethacin emulsion has been reported to increase ocular bioavailability and efficacy compared to commercially available formulation in rabbits. 0.4% indomethacin emulsion showed 2.2 fold increase in the area under the anterior aqueous drag concentration/time curve compared to a 1% indomethacin suspension. The emulsion formulation also reduced ocular surface irritation caused by indomethacin Similar advantages have been shown for a pilocarpine emulsion which produced a prolonged therapeutic effect in comparison with pilocarpine hydrochloride eyedrops in man. It can be administered only twice a day, rather than four times daily for conventional formulation. 

Biotransformations, biocorrversions impact on the whole range of biological, biotechnological arrd biomedical applications, such as in the analysis of genes and transcripts, the therapeutic treatment of abnormal molecules in diseases, the construction of specific enzymes and proteins for therapy, analysis, production, the assembly and constixiction of synthetic bio-synthetic pathways in organisms for the synthesis of intermediates, antibiotics, vitamins, enzymes, flavors. 

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