Stability of fat-soluble and water-soluble vitamins in artificially prepared, vitamin-enriched, lyophilized serum

Stability of fat-soluble and water-soluble vitamins in artificially prepared, vitamin-enriched, lyophilized serum
June 2004
Hiroshi Ihara 1, Naotaka Hashizume 1, Tadashi Matsubayashi 2, Koichi Futaki 2, Masayuki Yoshida 3, Naotoshi Sagawa 4, Makoto Fujisaki 4, Kazuo Mita 5, Akira Kadota 6
1Department of Laboratory Medicine, Ohashi Hospital, School of Medicine, Toho University, Tokyo, Japan
2Nissui Pharmaceutical Co., Ltd., Tokyo, Japan
3Roche Diagnostics K.K., Tokyo, Japan
4Mitsubishi-Kagaku Bio-Clinical Laboratories, Inc., Tokyo, Japan
5TSL, Inc., Tokyo, Japan
6Kyowa Medex Co., Ltd., Tokyo, Japan
Journal of Clinical Laboratory Analysis Volume 18, Issue 4, Date: 2004, Pages: 240-246
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Abstract
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?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?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. J. Clin. Lab. Anal. 18:240-246, 2004. ? 2004 Wiley-Liss, Inc.