Statistical analyses
PD
All statistical analyses were performed using SAS 9.4 programming (SAS Institute Inc., North Carolina, USA). PK and PD parameters were descriptively expressed as N, arithmetic mean, standard deviation (SD), coefficient of variation (CV), median, minimum, and maximum. Primary PK and PD parameters were analyzed using multivariate analysis of variance (ANOVA) after logarithmic conversion. The 90% confidence interval (CI) was used to evaluate the relative bioavailability of the drugs, with intraindividual CV (intra-CV%) calculated. The mixed-effect model was adopted in ANOVA, with treatment, period, and sequence of administration as fixed effects, and subjects (sequence of administration) as random effects. The relative bioavailability of the study drug was calculated by the ratio of the AUC value of the normalized dose of oral insulin to that under injection, as follows:Bioavailability = (AUCData were analyzed using nonparametric tests considering the small sample size of this study. The two-side test was used to determine the significances between pairs of measurements. Differences with 