A comparison of the plasma glucose and insulin day profiles between two prandial rapid-acting insulin analogues, insulin glulisine (glulisine) and insulin lispro (lispro), in 18 obese subjects with Type 2 diabetes. Subjects (body mass index: males, 36.7 [33.2-43.8] kg/m(2); females, 40.0 [35.7-46.5] kg/m(2)) received subcutaneous glulisine or lispro (0.15 U/kg) at 4-h intervals immediately (within 2 min) before three standard test meals during each of two 12-h, randomised, open-label, crossover studies (7+/-2-day interval between each). Overall, preprandial-subtracted glucose concentrations (area under the curve) were similar on the glulisine and lispro study days. However, the mean of the three maximal preprandial subtracted plasma glucose concentrations (DeltaGLU(max)) were lower with glulisine versus lispro (12%; p<0.01). Mean concentrations of insulin analogue were significantly higher post-meal with glulisine (p<0.01 for all). Post hoc analysis showed a significantly faster absorption rate for glulisine versus lispro in the first 30 min post-meal (estimated difference 0.48 microU/min; p<0.0001). Only two cases of hypoglycaemia were reported; both from one subject during the lispro day. When glulisine is injected immediately before a meal in obese patients with Type 2 diabetes, glulisine achieves significantly lower glucose excursions over lispro. Significantly faster absorption with higher and sustained post-meal levels of insulin analogue was achieved at every meal with glulisine versus lispro.