Dose-response relationship of an oral insulin spray in six patients with type 1 diabetes: a single-center,...

This study evaluated the pharmacokinetic and pharmacodynamic properties and dose-response effects of an oral insulin spray formulation compared with those of subcutaneously injected regular insulin and placebo in patients with type 1 diabetes mellitus.

This was a single-center, randomized, single-blind, open-label, 5-way crossover study in which patients with type 1 diabetes received 5, 10, and 20 puffs of the oral insulin spray; regular insulin 0.1 U/kg SC; and placebo spray. The pharmacokinetic parameters of interest were the maximum serum insulin concentration (Ins-C(max)); the incremental insulin AUC from 0 to 120 minutes (Ins-AUC(0-120)), from 0 to 240 minutes, and from 0 to 360 minutes; and the time to maximum serum insulin concentration (Ins-T(max)). The pharmacodynamic parameters of interest were the maximum glucose infusion rate (GIR(max)); the incremental glucose AUC from 0 to 120 minutes (GIR-AUC(0-120)), from 0 to 240 minutes, and from 0 to 360 minutes; the time to maximum GIR (GIR-T(max)); the time to early half-maximal GIR (early T50%); and the time to late half-maximal GIR (late T50%). Pharmacokinetic and pharmacodynamic parameters were assessed using the euglycemic clamp technique.

The study enrolled 6 white men with type 1 diabetes (mean [SD] age, 37.5 [16.2] years, mean weight, 82.7 [17.0] kg). Ins-T(max) was shorter for 5, 10, and 20 puffs of oral insulin spray than for SC insulin (26.7 [13.7], 29.2 [7.4], 23.3 [5.2], and 142.5 [73.2] min, respectively; P < 0.05). There was no effect of dose on Ins-T(max). The Ins-AUC(0-120) for 5, 10, and 20 puffs of oral insulin spray (304.8 [277.9], 689.2 [353.0], and 1808.8 [1252.6] microU/mL per min, respectively; P < 0.05) and the corresponding Ins-Ca(max) (12.9 [8.7], 26.7 [14.5], and 47.6 [40.1] microU/mL; P < 0.05) suggested a dose-response relationship. Five, 10, and 20 puffs of oral insulin spray had an earlier onset of action than SC insulin (early T50%: 23.3 [15.1], 28.3 [12.3], 31.2 [111.8], and 87.0 [39.6] min, respectively; P < 0.05), an earlier maximal effect (GIR-T(max): 40.0 [23.7], 45.8 [22.7], 44.2 [5.8], and 145.0 [43.7] min; P < 0.05), and a shorter duration of action (late T50%: 56.5 [31.0], 70.2 [12.9], 75.5 [6.0], and 290.8 [84.0] min; P < 0.05). Dose-dependent increases in maximal metabolic effect were observed with 5, 10, and 20 puffs: the GIR(max) was 0.9 (0.5), 2.0 (1.3), and 3.9 (2.5) mg/kg per minute, respectively (P < 0.05), and the GIR-AUC(0-120) was 39.6 (34.9), 76.8 (67.4), and 189.1 (163.0) mg/kg per minute (P < 0.05).

In this study in patients with type 1 diabetes, oral insulin spray had a faster onset and shorter duration of action than subcutaneously injected regular insulin. A dose-response relationship was noted in the metabolic effect and absorption of oral insulin spray.