For bone-seeking radiopharmaceuticals or radionuclides, for which the distribution of cumulated activity between the cortical and trabecular bone is unknown, the assumption is that substances with an effective half-time shorter than 15 days are surface-deposited; otherwise, they are distributed uniformly throughout the entire volume of trabecular and cortical bone [13].
The final gel elasticity as well as gelling rate seemed to follow a similar pattern for both types of particles although the final storage modulus was several times higher and gelation half time generally shorter when using strontium alginate as the gelling ion donor.
Reduced almond size led to a faster disintegration rate (shorter half time) and a higher level of swelling.
The problem is that GLP-1 has short half time in blood because it is cleaved and inactivated by dipeptidyl peptidase-4 (DPP-4) [ 145] making it impractical for routine use in patients.
The estimated half time for chrysotile is much shorter (of the order of a few months) due to leaching, macrophage removal and fragmentation.
Its short context sensitive half life (3-4 minutes) and short elimination half time 10-200 maketes) make it suitable for administration under the control of the patient for women in labour who want pain relief.
However, non-osteochondral specification, short plasma half time and bioactivity loss restrict growth factor's application.
However, these molecules have high instability and very short biological half time and can be enzymatically digested or deactivated while in physiological fluids [ 87, 88].
This is also illustrated by the high litter decay constants (k) and short half times (mean 1.6 year) for in situ litter decomposition in tropical and subtropical wetlands.
This surge of interest emerged from the finding that the analgesic effects of β-END were obvious only after icv-, anotnot after iv-administration [ 348, 351– 355] This difference illustrated clearly the relative effects of the rather impenetrable blood brain-barrier comblood brain-barrierst 3 times shorter half-life of β-END in the blood versus in the combinedut 37 min vs. about 97 min; [ 355].
The albumin half-life time is shorter and its transportation rate is higher in sepsis compared with control individuals [ 11], which results in inadequate availability of albumin to tissues in sepsis.
