Calcitonin administration route

Calcitonin (Miacalcin, Miacalcin Nasal Spray) is a synthetic 32-amino acid polypeptide that is identical to salmon calcitonin. Salmon calcitonin is more potent than human calcitonin because of its higher affinity for the human calcitonin receptor and its slower metabolic clearance. Administration is by subcutaneous or intramuscular injection or by nasal spray. The absorption of the nasal form is slower than that of the parenteral routes. 

The oral bioavailability of a peptide was improved from 0.5 to 27% due to the co-administration of MCG (Constantinides et al. 1994). Lundin et al. (1997) demonstrated that monohexanoin is even more effective than MCG in increasing oral absorption of the therapeutic peptide dDAVP in rats. Furthermore, due to the co-administration of a monoolein/sodium taurocholate combination the colonic uptake of polyethylene glycol 4000, calcitonin and horseradish peroxidase in rats was significantly increased without causing morphologic damage to the mucosa. The appearance of horseradish peroxidase in the cytoplasm suggested enhancement via the transcellular route of uptake (Hastewell et al. 1994). 

Polyacrylic acid aqueous gel enhances the absorption of calcitonin after nasal as well as rectal administration. When [Asul,7]-eel calcitonin (lOU/kg) was administered nasally in polyacrylic acid gel at a concentration of 0.1% w/v, a prominent hypocalcemic effect was seen in the first 30min. Nasal administration of [Asul,7]-eel calcitonin in saline had no hypocalcemic effect at the same dose when given by the nasal route. In addition to this, the effect of [Asul,7]-eel calcitonin in the dose range of 1-10 U/kg has also been studied. The resulting data showed that a rapid reduction in plasma calcium concentrations can be achieved at doses of 5 and 10 U/kg however, at doses of 1 U/kg only a small reduction in the plasma calcium concentration was observed, suggesting that polyacrylic acid gel can be used for the intranasal administration of peptides such as calcitonin. The possible side effects, however, were not known at the time the study was performed [76-78],... 

New, R. R. C., Guard, P. W., Littlewood, G. M., and Flynn, M. J., 1994b, Changes in uiinaty crosslinks after administration of calcitonin to humans by subcutaneous and oral routes, Controlled Release Society 21st International Symposium, Nice, France, June. 

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