[Pharmacodynamics, pharmacokinetics and bioavailability of insulin enteric-coated soft capsules]

To study the pharmacokinetic and pharmacodynamic properties of the insulin enteric-coated soft capsules.

In this open, single-center, randomized, two-period, cross-over, euglycemic glucose clamp study, 20 healthy volunteers (14 men, 6 women), aged (28.6 +/- 5.2) years, whose BMI was (21.2 +/- 1.1) kg/m(2), received insulin enteric-coated soft capsules (50 IU) or regular insulin (15 IU) administration after a baseline period of 2 hours. After the administration, 29 blood samples were taken for serum insulin measurement. Meanwhile, glucose infusion rates (GIR) were determined per 5 minutes over a period of 12 hours.

The maximal concentration (Cmax) of insulin was (22.1 +/- 8.0) mIU/L vs (118.6 +/- 25.2) mIU/L (tested vs reference preparation); the time for reaching Cmax (Tmax) was (255.8 +/- 142.2) min vs (115.5 +/- 43.4) min. The maximal GIR (GIRmax) were (3.56 +/- 0.85) mg.kg(-1).min(-1) vs (4.87 +/- 1.26) mg.kg(-1).min(-1); the time for reaching GIRmax (T(GIRmax)) was (166.3 +/- 75.9) min vs (148.0 +/- 40.8) min. The relative bioavailability and bioefficacy of insulin enteric-coated soft capsules were (7.42 +/- 3.25)% and (24.78 +/- 0.08)%.

The difference between relative bioavailability and relative bioefficacy indicates that the oral administration of insulin enteric-coated soft capsules may mimic physiological procedure of insulin endosecretion. These pharmacokinetic and pharmacodynamic data provide a useful guide for further clinical trial.