Vitamin high potency

Spectrophotometric deterrnination at 550 nm is relatively insensitive and is useful for the deterrnination of vitamin B 2 in high potency products such as premixes. Thin-layer chromatography and open-column chromatography have been appHed to both the direct assay of cobalamins and to the fractionation and removal of interfering substances from sample extracts prior to microbiological or radioassay. Atomic absorption spectrophotometry of cobalt has been proposed for the deterrnination of vitamin B 2 in dry feeds. Chemical methods based on the estimation of cyanide or the presence of 5,6-dimethylben2irnida2ole in the vitamin B 2 molecule have not been widely used. 

In the human market, oral and parenteral dosage forms are prepared from the crystal. However, because of the extremely high potency, more dilute (0.1—10%) forms are avabable. These include dilutions with mannitol, triturations on dicalcium phosphate or resins, and spray-dried forms. Prices for these forms are driven by that of the crystal, which in early 1996 was ca 9.50/gram (95). Prices for the vitamin have risen during the first half of the 1990s. However, Htde growth in price beyond inflation is anticipated. 

One-A-Day 50 Plus One-A-Day Essential One-A-Day Maximum Theragran-M Advanced High Protein Theragran-M Premier High Potency Theragran-M Premier 50 Plus High Potency Therapeutic Vitamin + Minerals Unicap M Unicap Sr. 

KH Hanewald, FJ Mulder, KJ Keuning. Thin-layer chromatographic assay of vitamin D in high-potency preparations. J Pharm Sci 57 1308-1312, 1968. 

The vitamin D potency of milk can be increased in several ways by feeding cows substances that are high in vitamin D activity, such as irradiated yeast by irradiating milk and by adding vitamin D concentrates. The latter method is now the only commonly used procedure. The practice of irradiating milk to increase the vitamin D potency has been discontinued, undoubtedly because of the deteriorative action of the radiation on other milk components. Vitamin D is added to milk to provide a concentration of 400 IU... 

There have been no reports of toxicity and no Tolerable Upper Intake Levels. Because its active transport is saturable, excessive uptake is doubtful. Also, this vitamin does not have the mystique that would prompt marketing "high potency" formulations. 

High potency Individual vitamins or minerals at 100 % or more of the RDI per reference amount customarily caisumed... 

WE is caused by acute thiamine (Vitamin B ) deficiency - ejq)lain the risks and prescribe high potency B vitamins ITable 40.41. Pabrinex triggers anaphylaxis extremely rarely, but ensure adrenaline 0.5 mg IM is prescribed and available. 

Vitamin overdoses (hypervitaminoses)— The best known vitamin toxicities are those which result from vitamin A and vitamin D, because (1) these vitamins are fat soluble, (2) small amounts of them have strong effects, and (3) they tend to accumulate in the liver. Toxic effects do not occur so readily with vitamins E and K, which are also fat-soluble, unless high potency supplements are taken. 

High potency preparations of vitamin B-12 are usually assayed by spectrophotometry. Also, vitamin B-12 may be assayed colorimetrically or fluorometrically. Some assays involve measurement of cobalt. However, food sources are usually assayed for vitamin B-12 by either (1) the microbiological method, or (2) the biological method, using chicks or rats. 

Both vitamin D, and Dj give a yellow-orange color with antimony trichloride. This color reaction forms the basis of the USP XVIII method for vitamin D. Since color reactions are subject to interferences from many sources, they should be limited to high potency pharmaceutical preparations or fortified foods. Combinations of column and thin-layer chromatographic purification steps with the antimony trichloride reaction have been successfully used. 

In the presence of vitamin A the vitamin may be extracted with organic solvent either directly or after saponification with ethanolic potassium hydroxide. Both vitamins Dg and D3 have identical spectra with broad bands having maxima at 265 m in hexane but the extinction coefficients in this solvent are comparatively low, being 459 for and 474 for D3, and the more intense absorption of vitamin A, with its peak at 328 m//, may completely overshadow the absorption of vitamin D. The spectro-photometric method therefore requires separation of vitamin D from vitamin A and other absorbing materials and can only be applied to comparatively high-potency materials. 

Children with xerophthalmia and measles should be treated immediately with oral, high-potency vitamin A (200,000 lU) according to WHO and IVACG guidelines (Table 5) and provided other supportive nutritional and medical therapy as indicated. Corneal lesions should be topically treated with a suitable antibiotic (e.g., tetracycline or chloramphenicol) to prevent bacterial infection. Corneal xerophthalmia typically improves with VA treatment within 1 week, with complete resolution within 4 weeks. 

A. crystallizes in colorless and odorless platelets, which are easily soluble in water or ethanol. It possesses a strong acidic taste and a high reducing power (di-enolic constitution). Aqueous solutions are rapidly oxidized by air. From 4 possible stereoisomers (- isomerization), only the L-threo configuration has vitamin C potency. 

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