The feasibility of self-dissolving micropiles (SDMP) as a percutaneous delivery system of recombinant human growth hormone (rhGH) has been studied in rats using SDMP where dextran was used as a base. After mixing dextran solution with rhGH, SDMPs were prepared by pulling with polypropyrene tips. The mean weight, length and diameter were 0.68±0.05 mg, 3.2±0.5 mm and 0.6±0.2 μm, respectively. To evaluate the bioavailability (BA) of rhGH percutaneously administered by SDMP, an absorption experiment was performed in rats. RhGH SDMPs were inserted into the rats skin, 200 μg kg−1, and plasma rhGH levels were measured by an ELISA method. Peak plasma rhGH level, 132.8±11.8 ng ml−1, appeared at 0.8±0.2 h. By comparing the plasma rhGH levels vs. time profiles after the administration of SDMP and intravenous injection of rhGH solution, 5 μg kg−1, BA of rhGH from SDMP was calculated to be 87.5%. Theses results may suggest that SDMP can be used as a novel percutaneous drug delivery system.
2008 The Pharmaceutical Society of Japan