Differences in formulation and bioavailability of commercial injectable fat-soluble vitamin products

Wednesday, July 23, 2014
Exhibit Hall AB (Kansas City Convention Center)
D. B. Snider , Iowa State University, Ames, IA
R. A. Zinn , University of California-Davis, El Centro, CA
R. L. Stuart , Stuart Products Inc, Bedford, TX
Abstract Text:

Injectable fat-soluble vitamins are utilized more quickly and efficiently than oral products.  The major concern with injectables is chemical form and bioavailability of vitamins.  A commercial product (VITAL EAD (V); Stuart Products, Inc.) contains retinyl palmitate, the storage form of vitamin A, and another commercial product (Natural EAD (N); Neogen Corp.) contains retinyl propionate. Otherwise, vitamin D and vitamin E sources and  concentrations were the same.  Two experiments were conducted to compare bioavailability of vitamins E and A.  Exp 1 compared bioavailability in serum collected at 0, 24, 48 and 72 h. post-injection, and Exp 2 compared bioavailability at 0, 4, 8, 12 and 24 h post-injection.  All serum samples were analyzed for α-tocopherol and total vitamin A.  Exp 1 utilized ten animals (130 kg), and Exp 2 utilized eight animals (200 kg).  In Exp 1, five animals were injected with 5 mL of either product to provide 500,000 I.U. A, 50,000 I.U. D and 1,500 I.U.E  per animal.  In Exp 2, four animals were injected with 6 mL of either product to provide 600,000 I.U. A, 60,000 I.U. D and 1,800 I.U. E per animal.  In Exp one, serum α-tocopherol concentrations at 0, 24, 48, and 72 h for V-injected animals were 0.48, 20.02, 5.22, and 4.05 µg/mL, respectively.  Total vitamin A concentrations were 0.13, 5.85, 3.39, and 4.18 µg/mL, respectively.  For N, serum α-tocopherol concentrations were 0.57, 5.72, 3.74 and 4.00 µg/mL; and total serum vitamin A concentrations were 0.13, 0.17, 0.07, and 0.08 µg/mL for the four sampling times.  At 24 and 48 h samplings, serum α-tocopherol concentrations were different between the two products (P<0.01). For total vitamin A, all sampling periods were different (P<0.001).  In Exp 2, serum α-tocopherol concentrations at 0, 4, 8, 12, and 24 h were 1.13, 15.50, 28.30, 23.8 and 20.3 µg/mL, respectively and total vitamin A concentrations were 0.22, 3.05, 8.34. 8.49, and 11.87 µg/mL for the V-injected animals.  For N, serum α-tocopherol concentrations were 1.15, 5.25, 7.18, 7.00, and 8.95 µg/mL; and serum total vitamin A concentrations were 0.25, 0.32, 0.31, 0.30 and 0.39 µg/mL for the five time periods.  All post-injection times 24 h and below were significantly different (P<0.01) in favor of V.  The basis for differences in bioavailability of the injectable vitamin A forms, notwithstanding similar label concentrations is uncertain and warrants further consideration.


vitamin E, vitamin A, injectable, bioavailability