[Intranasal absorption of various calcitonin spray preparations]

In a cross-over study performed on 10 patients the intranasal absorption of calcitonin contained in three formulation spray was evaluated. One of them contained biliary acid (sodium taurocholate) as the absorption promoting factor while the other two drugs did not. The dosage of calcitonin in blood was effected by means of radioimmunoassay using salmon calcitonin marked with I126 in competition to the one present in the sample for a limited quantity of specific antibodies for salmon calcitonin. The minimum measurable quantity of calcitonin is 10 pg and the response is linear including values between 20% and 80%. It is observed that the plasmatic concentration of calcitonin dosed in different times after administration of the drug containing sodium taurocholate are always significantly higher (Student "t" test for unpaired data, p less than 0.005) than the measurements after administration of the other two drugs. They are about 8 times higher at the first half an hour, about 6 times after an hour and again double at the second hour. The AUC calculated for sodium taurocholate containing drug (1629 pg/ml/h) results significantly higher in relation to the other two drugs (1133 and 926 pg/ml/h) indicating a better bio-availability of calcitonin contained in that spray. The relative bioavailability between calcitonin spray with sodium taurocholate and the other two drugs in reference resulted to 144% and 176%. The presence of a transmucosal absorption promoting factor at the level of a nasal mucosa, represented in this case by sodium taurocholate, enhances significantly the absorption and the bioavailability of calcitonin present in the formulation spray.