Results
Forty-seven subjects underwent medical screening. Twenty-four subjects (male:female ratio 1:1) with Fitzpatrick skin type II were administered 40 mg adalimumab (volume of 0.4 mL) i.d. or s.c. in the lateral upper thigh and placebo (volume of 0.4 mL) s.c. or i.d. in the contralateral thigh. One subject was randomized but excluded before treatment due to medical reasons and replaced (Figure 1 ). The mean age was 26.1 years (range 20-42). Demographic characteristics were comparable between groups (Table 1 ). For both s.c. and i.d. adalimumab injections a minor spill (1-15% of intended volume not injected) occurred in 2 of 12 (17%) injections, and there was one (8%) major spill (15-50% of intended volume not injected) in an i.d. adalimumab injection. Both the minor spills and the major spill during i.d. injection occurred when high resistance during injection was encountered, whereas the minor spill of s.c. injection was due to backflow. Inspection of the hollow microneedles after injection using bright field microscopy did not show damaged microneedle tips (not shown).