Pharmacokinetics of recombinant human growth hormone administered by cool.click？ 2, a new needle-free device, compared with subcutaneous administration using a conventional syringe and needle

The study was performed with 38 healthy volunteers who underwent pituitary somatotrope cell down-regulation using somatostatin, according to a randomized, two-period, two-sequence crossover design. Following subcutaneous administration of r-hGH using cool.click？ 2 or needle and syringe, pharmacokinetic parameters were analysed by non-compartmental methods. Bioequivalence was assessed based on log-transformed AUC and Cmax values.The 90% confidence intervals for test/reference mean ratio of the plasma pharmacokinetic variables Cmax and AUC0-inf were 103.7–118.3 and 97.1–110.0, respectively, which is within the accepted bioequivalence range of 80–125%. r-hGH administered by cool.click？ 2 is, therefore, bioequivalent to administration by needle and syringe with respect to the rate and extent of GH exposure. Treatment using cool.click？ 2 was found to be well tolerated. With cool.click？ 2 the tmax was less (3.0 hours) than for needle and syringe delivery (4.5 hours), p = 0.002 (Friedman test), although this is unlikely to have any clinical implications.These results demonstrate that cool.click？ 2 delivers subcutaneous r-hGH exposure that is bioequivalent to the conventional mode of injection. The new device has the additional advantage of being needle-free, and should help to increase patient adherence and achieve good therapeutic outcomes from r-hGH treatment.Growth hormone deficiency (GHD) affects both children and adults, and clinical manifestations vary depending on the age of onset [1]. Children present with short stature and low growth rate [2], while adults have altered body composition and metabolism with reduced physical performance [3]. At all ages, quality of life is impaired [4,5].For many years, replacement therapy using exogenous human growth hormone (GH) has been used successfully to treat children with GHD [6], and has more recently benefited adult patients with GHD [7]. GH is now produced using recombinant DNA technology [8], and is also used to treat gro