Stability of fat-soluble and water-soluble vitamins in artificially prepared, vitamin-enriched, lyophilized serum.
Vitamin-enriched, lyophilized serum (VES) was prepared for an inter-laboratory study to compare vitamin assays. The VES contained water-soluble vitamins (vitamin B1, vitamin B12, vitamin C, and folate), fat-soluble vitamins (vitamin A and vitamin E), and cholesterol. We performed stability studies and determined vitamin concentrations and total cholesterol in VES stored at -20 degrees C for 12 months. Our recovery of the water-soluble vitamins in reconstituted VES was 70-142%, but we recovered only 33-45% of the fat-soluble vitamins. Physicochemical properties, such as specific gravity and viscosity of the reconstituted VES did not affect manual or automated measurements of these vitamins. Vial-to-vial differences found for the VES were the same as the within-day analytical variations. There was no evidence of degradation of vitamin A, vitamin B1, vitamin B12, vitamin C, folate, and cholesterol over 12 months in VES stored at -20 degrees C. Following deproteinization, vitamin C concentration was found to be lower than when not deproteinated. Vitamin E was less stable in VES, however, and the degradation during 12 months was lower than the between-day analytical variation of the assay. Our VES is the first preparation of lyophilized control serum that contains water-soluble and fat-soluble vitamins.
Ihara
Hiroshi
H
Department of Laboratory Medicine, Ohashi Hospital, School of Medicine, Toho University, Tokyo, Japan. ihara-1@cam.hi-ho.ne.jp
Hashizume
Naotaka
N
Matsubayashi
Tadashi
T
Futaki
Koichi
K
Yoshida
Masayuki
M
Sagawa
Naotoshi
N
Fujisaki
Makoto
M
Mita
Kazuo
K
Kadota
Akira
A
D001205:Ascorbic Acid / Q000097:blood; D002784:Cholesterol / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D015925:Cryopreservation; D004355:Drug Stability; D005492:Folic Acid / Q000097:blood; D005612:Freeze Drying; D006801:Humans; D012016:Reference Values; D013831:Thiamine / Q000097:blood; D014801:Vitamin A / Q000097:blood; D014805:Vitamin B 12 / Q000097:blood; D014810:Vitamin E / Q000097:blood; D014815:Vitamins / Q000097:blood*
D014815:Vitamins; D014801:Vitamin A; D014810:Vitamin E; D005492:Folic Acid; D002784:Cholesterol; D014805:Vitamin B 12; D001205:Ascorbic Acid; D013831:Thiamine