The Analysis of Vitamins 维生素类药物分析

掌握维生素B1、维生素C、及其制剂的鉴别、检查和含量测定方法 熟悉维生素A的鉴别和含量测定方法 了解维生素D、E的鉴别和含量测定方法

CHARACTERS 性质 Retinol acetate occurs as pale-yellow crystals (melting point about 60 ﾟC). Once melted retinol acetate tends to yield a supercooled melt. Retinol propionate occurs as a reddish-brown oily liquid. Retinol palmitate is a fat-like, light yellow solid or a yellow oily liquid, if melted (melting point about 26ﾟC). All retinol esters are practically insoluble in water, soluble or partly soluble in ethanol and miscible with organic solvents. Vitamin A and its esters are very sensitive to the action of air, oxidising agents, acids, light and heat. Carry out the assay and all tests as rapidly as possible, avoiding exposure to actinic light and air, oxidising agents, oxidation catalysts (e.g. copper, iron), acids and heat; use freshly prepared solutions.

R = H. C20H30O. 286. 5. R = CO-CH3. C22H32O2. 328. 5. R = CO-C2H5 R = H C20H30O 286.5 R = CO-CH3 C22H32O2 328.5 R = CO-C2H5 C23H34O2 342.5 R = CO-C15H31 C36H60O2 524.9

ASSAY UV 三点校正法

Impurities A. R = H, CO-CH3: kitols (Diels-Alder dimers of vitamin A),

B,(3E,5E,7E)-3,7-dimethyl-9-[(1Z)-2,6,6-trimethylcyclohex-2-enylidene)nona-1,3,5,7-tetraene (anhydro-vitamin A),

C. (3E,5E,7E)-3,7-dimethyl-9-[(1Z)-2,6,6-trimethylcyclohex-2-enylidene)nona-3,5,7-trien-1-ol (retro-vitamin A), D. Oxidation products of vitamin A.

1 IU of vitamin A 0.344 mg of all-(E)-retinol acetate, 0.359 mg of all-(E)-retinol propionate, 0.550 mg of all-(E)-retinol palmitate, 1 mg of retinol equivalent is equivalent to 3333 IU.

Impurities

维生素B1 Thiamine Hydrochloride C12H17ClN4OS,HCl 337.3

Appearance White or almost white, crystalline powder or colourless crystals Solubility Freely soluble in water, soluble in glycerol, slightly soluble in alcohol

Identification Thiochrome 硫色素反应 条件、现象、应用、原理 沉淀反应、氯化物 Dissolve about 20 mg in 10 ml of water R, add 1 ml of dilute acetic acid R and 1.6 ml of 1M sodium hydroxide, heat on a water-bath for 30 min and allow to cool. Add 5 ml of dilute sodium hydroxide solution R, 10 ml of potassium ferricyanide solution R and 10 ml of butanol R and shake vigorously for 2 min. The upper alcoholic layer shows an intense light-blue fluorescence, especially in ultraviolet light at 365 nm. Repeat the test using 0.9 ml of 1M sodium hydroxide and 0.2 g of sodium sulphite R instead of 1.6 ml of 1M sodium hydroxide. Practically no fluorescence is seen. 沉淀反应、氯化物

Impurities 杂质检查 酸碱度 硫酸盐 重金属

Impurities A. R1 = CH3, R2 = O-SO3-: 3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-4-methyl-5-[2-(sulphonatooxy)ethyl]thiazolium (thiamine sulphate ester), B. R1 = H, R2 = OH: 3-[(4-aminopyrimidin-5-yl)methyl]-5-(2-hydroxyethyl)-4-methylthiazolium (desmethylthiamine), C. R1 = CH3, R2 = Cl: 3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-5-(2-chloroethyl)-4-methylthiazolium (chlorothiamine),

Assay 含量测定 原料药：容量分析、UV法、重量法、 制剂： UV法

维生素C Ascorbic Acid C6H8O6 176.1

Identification

CHARACTERS A white or almost white, crystalline powder or colourless crystals, becoming discoloured on exposure to air and moisture, freely soluble in water, soluble in alcohol, practically insoluble in ether. It melts at about 190 ﾟC, with decomposition.

IDENTIFICATION