ABSTRACT
The influence of duration and of various routes of administration of native levan on blood levels of the drug was studied in mice. The blood levels varied with the doses administered. With a single i.p. injection of 20 mg levan/mouse the blood levels rose more rapidly than with higher and lower doses. In the second and third week of daily injections the rise and fall in blood levels became less pronounced. With treatment longer than 3 weeks spikes of maximal concentrations reappeared. After s.c. injections blood levels rose more slowly than after i.p. treatment. The findings indicate that: 1. high doses slow down absorption of levan; 2. after 7-21 days of treatment the RES (reticulo endothelial system) is more active in removal of levan from the blood stream than at the beginning of the treatment; 3. after treatment of 3 weeks and more the RES appears to be blocked and is again slow in the uptake of levan from the blood stream.
