Availability of synthetic salmon calcitonin in tissue fluid after a single intravenous dose

To obtain further information about the availability of salmon calcitonin in the biophase compartment that surrounds the receptor site, salmon calcitonin concentrations in plasma and skin blister fluid (SBF) after a single IV dose of 100 IU synthetic salmon calcitonin were compared in 15 healthy volunteers.Serial blood and SBF samples were collected before and up to 8 h after administration and calcitonin was determined by a specific RIA.The maximum concentration in plasma was 225 pg·ml^-1 (in the first sample at 15 min), whereas in SBF the mean peak of 84 pg·ml^-1 was reached after about 30 min. The distribution of salmon calcitonin into SBF, defined as the ratio of the AUCs in SBF and plasma, was 1.5. The kinetic profiles of salmon calcitonin in plasma and interstitial fluid were different. Calcitonin in plasma peaked and then levelled out, while in SBF it persisted longer than in plasma.This is the first report of the distribution of salmon calcitonin into blister fluid.