Synthetic vitamins

Vitamins. The preparation of heat-sensitive natural and synthetic vitamins (qv) involves solvent extraction. Natural vitamins A and D are extracted from fish Hver oils and vitamin E from vegetable oils (qv) Hquid propane [74-98-6] is the solvent. In the synthetic processes for vitamins A, B, C, and E, solvent extraction is generally used either in the separation steps for intermediates or in the final purification. 

World production ia the late 1990s of both natural and synthetic forms of vitamin E is estimated at 22,000 metric tons and growth is expected to keep pace with increasing need. The 1993 U.S. production was 14,096 metric tons (47) with an additional 1080 metric tons from imports. The principal U.S. producers of the natural form are Eastman Chemical Company, Archer Daniels Midland Company, and Henkel, and of synthetic vitamin E, Hoffmaim-La Roche and BASE. International producers include Hoffmaim-La Roche, BASE, Eisai, and Rhc ne-Poulenc. 

The price of synthetic vitamin E decreased steadily until about 1990 when prices began to increase. The price of the natural form, although higher than the synthetic form, has approximately paralleled the synthetic form (Table 4). 

C I l5CO()[ I, which is used in medicinal research and in the manufacture of synthetic vitamin A, is 2.69. What is the Ka of crotonic acid ... 

Thus, synthetic vitamin E is purified by short-path distillation under high vacuum or by extraction with SC CO2 (Baldenius et al., 1996). 

This is not an efficient method for the preparation of synthetic Vitamin C owing to the difficulty of obtaining L-threose.28... 

Calcipotriene (Dovonex) is a synthetic vitamin D analog used for mild to moderate plaque psoriasis. Improvement is usually seen within 2 weeks of treatment, and approximately 70% of patients demonstrate marked improvement after 8 weeks. Adverse effects occur in about 10% of patients and include lesional and perilesional burning and stinging. Calcipotriene 0.005% cream, ointment, or solution is applied one or two times a day (no more than 100 g/wk). 

Increase in vitamins, such as niacin, riboflavin pantothenic acid, Vitamin Be and Vitamin B12, is of great nutritional significance, especially where fortifying foods with synthetic vitamins is not practiced. 

Calcipotriene (Dovonex), a synthetic vitamin D3 derivative, is indicated for the treatment of moderate plaque psoriasis. Its mechanism of action is unknown, although it competes for calcitriol receptors on keratinocytes and normalizes differentiation. It also has a variety of immunomodulatory effects in the skin. Although the drug can cause local irritation, the most serious toxicities are hypercalciuria and hypercalcemia, which are usually reversible. 

Mechanism of Action A synthetic vitamin Dj analog that regulates skin cell (kerat-inocyte) production and development. Therapeutic Effect Preventing abnormal growth and production of psoriasis (abnormal kerafinocyte growth). Pharmacokinetics Minimal absorption through intact skin. Metabolized in liver. 

It is a synthetic vitamin derivative effective in the treatment of plaque type psoriasis vulgaris. Adverse effects include itching and mild irritation. 

Doxercalciferol, the active ingredient in Hectorol, is a synthetic vitamin D analog that undergoes metabolic activation in vivo to form 1 (alpha),25-dihydroxyvitamin D2 (l(alpha),25-(OH)2D2), anaturally occurring, biologically active form of vitamin D2. Hectorol is available as soft... 

Vitamin C Is the Synthetic Vitamin as Good as the Natural One A claim put forth by some purveyors of health foods is that vitamins obtained from natural sources are more healthful than those obtained by chemical synthesis. For example, pure L-ascorbic acid (vitamin C) extracted from rose hips is better than pure L-ascorbic acid manufactured in a chemical plant. Are the vitamins from the two sources different Can the body distinguish a vitamin s source ... 

Another important family of quinones, related in structure to those already discussed, are the vitamins K (Fig. 15-24, Box 15-F). These occur naturally as two families. The vitamins K, (phylloquinones) have only one double bond in the side chain and that is in the prenyl unit closest to the ring. This suggests again the possibility of chromanol formation. In the vitamin K2 (menaquinone) series, a double bond is present in each of the prenyl units. A synthetic compound menadione completely lacks the polyprenyl side chain and bears a hydrogen in the corresponding position on the ring. Nevertheless, menadione serves as a synthetic vitamin K, apparently because it can be converted in the body to forms containing polyprenyl side chains. 

KUHN, RICHARD (1900-1967). A German chemist who won the Nobel prize for chemistry in 1938. He worked on cartinoids and synthetic vitamins and discovered the chemical formula for vitamin B6. He also... 

Citrus juice is rich in ascorbic acid and, therefore, is an important dietary source of this essential vitamin. Our studies were aimed at defining whether vitamin C from citrus sources is comparable with the synthetic vitamin in terms of bioavailability and intestinal absorption. These studies were conducted using human volunteers and guinea pig experimental models (1, 2). 

To address the question of whether the biological antioxidant would withstand the high melt processing temperatures, dl-a-tocopherol (synthetic vitamin E) was extruded at different concentrations in PE and PP under different processing temperatures ranging from 210 °C to 285 °C. Similar experi-... 

It is clear that the idealism set out initially in the principles of organic agriculture has had to be tempered by practical considerations. The standards adopted have to aim for a balance between the desire of consumers for organic products and considerations of ethical and ecological integrity and the practical and financial needs of producers. As a result, synthetic vitamins are now allowed in organic poultry feeds, with some restrictions. 

One very useful feature of the regulations is the inclusion of a detailed list of permitted feed ingredients (see Chapter 4, this volume). More countries should follow the New Zealand example. The minerals and trace elements used in animal feeding have to be of natural origin or, failing that, synthetic in the same form as natural products. Synthetic vitamins identical to natural vitamins are allowed. Roughage, fresh or dried, or silage must be added to the daily ration for poultry but the quantity is not specified. 

Prior to the availability of synthetic vitamins Dg and D3, fish liver oils were the primary sources of vitamin D3. The commonly used oil is that from... 

Natural, as opposed to synthetic, vitamin D has its advocates (F9), i.e., vitamin D3 as opposed to vitamin D2. Again there is suggestive evidence that if ingested vitamin D plays any part in the etiology of idiopathic hypercalcemia of infancy, it is vitamin D2 particularly which comes under suspicion. 

Under the denomination of vitamin E are collected eight different isomers that are present in nature and particularly in oils commonly used as food, The synthetic vitamin E is the all racemic a-tocopherol (ART), whereas the natural vitamin E is the RRR a-tocopherol (RRRT). 

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