Naoki Nambu

APPLICATION OF CHITIN AND CHITOSAN TO PHARMACEUTICAL PREPARATIONS

With a view towards application of chitin and chitosan in pharmaceutical preparations, investigations were done on directly compressed tablets containing chitin or chitosan, sustained-release preparations of water-soluble drugs with chitosan, and dissolution properties and bioavailability of poorly soluble drugs from ground mixtures with chitin or chitosan.

Percutaneous absorption of propranolol from gel ointment in rabbits

Abstract The percutaneous absorption in rabbits of propranolol from an alcohol-based gel ointment was studied to find a possible formulation of a transdermal dosage form which achieves a systemic effect. Gel ointments containing 1% propranolol were prepared by mixing ethanol/propylene glycol (EtOH/PG, 2:1 v/v) with 0.6 g Carbopol 934 in different amounts of water. The sum of the volumes of water and EtOH/PG was kept constant. The amount of propranolol released from the gel ointment as a function of the EtOH/PG content showed a convex relationship, giving a maximum release around 45–55% EtOH/PG. The solubility data for propranolol in various (EtOH/PG)/water mixtures indicated that a content of about 55% EtOH/PG was required to dissolve 1% propranolol in the gel ointment. In the study of percutaneous absorption of propranolol in rabbits, a gel ointment of 55% EtOH/PG, which was prepared according to the solubility data mentioned above, gave a distinctly high plasma level as compared with an ointment containing 40% EtOH/PG and conventional ointments. The mean plasma level obtained using 55% EtOH/PG, about 60 μng/ml, was comparable to the levels used for therapeutic purposes in human.

Effect of ?-cyclodextrin on disposition of hexobarbital and phenobarbital in mice

The effect of β-cyclodextrin (β-CD) on the disposition of hexobarbital (HBA) and phenobarbital (PhBA) after intravenous administration,with the simultaneous administration with β-CD, was investigated in mice.