CHEMICAL AND BIOLOGICAL STABILITY OF CRYSTALLINE VITAMINS D2 AND D3 AND THEIR DERIVATIVES

Abstract

Fritz, Halpin, Hooper, and Kramke (1) presented evidence that vitamin D is not stable when added to various dry carriers as it must be added of necessity to mixed feeds.The carriers used include dried whey, sucrose, oyster shell, mineral mixtures, sand, kaolin, and MnS04 in mixtures with such solvents as ether, corn oil, tuna oil, and the U.S.P. reference oil with a menstruum such as cereals and ground corn.Instability is due to numerous substances or conditions that promote oxidation.Temperature coefficients and other data indicate that the destruction is due to a chemical reaction.Thus, all forms of vitamin D, including activated ergosterol in a crystalline form or when adsorbed on casein (ertron), activated T-dehydrocholesterol (crystalline vitamin D3), as well as vitamin D from natural sources, are susceptible to destruction.This change occurs more rapidly in a dry dispersed state than in emulsions.Various methods for stabilizing vitamin D have been tested.The most effective protection is afforded by coatings which prevent contact with air.Thus, coating agents such as dried whey with hydrogenated fats and calcium stearate impart materially more stability than does whey alone.Mineral mixtures deteriorated rapidly, but were satisfactorily stabilized by hydrogenated fats or even molasses.Packing in inert gases additionally retards the rate of destruction.Baird, Ringrose, and MacMillan (2) reported that the vitamin D content of chick ration fortified with cod liver oil and stored at summer temperatures for 32 weeks showed no measurable destruction.Jung (3) noted that peanut oil solutions of vitamin DS were less stable than similar solutions of vitamin Dz, but the stability on addition of stabilizing substances such as yeast, alfalfa meal, and CaC03 was satisfactory.The present report deals with the stability of crystalline D vitamins and their derivatives per se, as well as when incorporated in pharmaceutical preparations.During the last 4 years large amounts of vitamins Dt and Da and their derivatives have gone through our hands and we have tried to establish their data in terms of melting point, specific rotation, and ultraviolet ab-125