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We report successful oral administration of insulin entrapped in amidated pectin hydrogel beads in streptozotocin (STZ)-diabetic rats, with a concomitant reduction in plasma glucose concentration. The pectin–insulin (PI) beads were prepared by the gelation of humilin–pectin solutions in the presence of calcium. Separate groups of STZ-diabetic rats were orally administered two PI beads (30 µg insulin) once or twice daily or three beads (46 µg) once daily for 2 weeks. Control non-diabetic and STZ-diabetic rats were orally administered pectin hydrogel drug-free beads. By comparison with control non-diabetic rats, untreated STZ-diabetic rats exhibited significantly low plasma insulin concentration (0· 320· 03 ng/ml, n= 6, compared with 2· 600· 44ng/ml in controls, n= 6) and increased plasma glucose concentrations (25· 841· 44 mmol/l compared with 10· 72 0· 52 mmol/l in controls). Administration of two PI beads twice daily (60 µg active insulin) or three beads (46 µg) once a day to STZ-diabetic rats increased plasma insulin concentrations (0· 890· 09ng/ml and 1· 85 0· 26 ng/ml, respectively), with a concomitant reduction in plasma glucose concentration (15· 451· 63 mmol/l and 10· 560· 26mmol/l, respectively). However, a single dose of PI beads (30 µg) did not affect plasma insulin concentrations, although plasma glucose concentrations (17· 822· 98 mmol/l) were significantly reduced compared with those in untreated STZ-diabetic rats. Pharmacokinetic parameters in STZ-diabetic rats show that the orally administered PI beads (30 µg insulin) were more effective in sustaining plasma insulin concentrations than was sc insulin (30 µg). The data from …