About 3-8 mcg of B 12 is secreted into the GI tract daily via the bile; in normal subjects with sufficient intrinsic factor, all but about 1 mcg is reabsorbed. When B 12 is administered in doses which saturate the binding capacity of plasma proteins and the liver, the unbound B 12 is rapidly eliminated in the urine. Retention of B 12 in the body is dose-dependent. About 80-90% of an intramuscular dose up to 50 mcg is retained in the body; this percentage drops to 55% for a 100 mcg dose, and decreases to 15% when a 1000 mcg dose is given.
A new development is the 2K (two component) aerosol. A 2K aerosol device has main component stored in main chamber and a second component stored in an accessory container. When applicator activates the 2K aerosol by breaking the accessory container, the two components mix. The 2K aerosol can has the advantage for delivery of reactive mixtures. For example, 2K reactive mixture can use low molecular weight monomer , oligomer , and functionalized low molecular polymer to make final cross-linked high molecular weight polymer. 2K aerosol can increase solid contents and deliver high performance polymer products, such as curable paints , foams , and adhesives .