beta-Interferon (IFN) administered intranasally in solution or as a powder without surfactants was not absorbed in rabbits. However, absorption occurred after the addition of surfactants (non-ionic, anionic and amphoteric). Maximum concentrations of IFN in plasma were dependent on the surfactant used, sodium glycocholate being the most effective. Total absorption of IFN following nasal administration with sodium glycocholate was 2.2% of that following intravenous administration.

Administration, Intranasal↗

PubMed1986

Use of chitosan and hydroxypropylchitosan in drug formulations to effect sustained release.

This study was an attempt to develop implantable sustained release forms of drugs, based on formulations containing chitosan, a biodegradable polymer from a natural source, and hydroxypropylchitosan (HP-chitosan), its water-soluble derivative. The possibilities were explored using uracil as a model for anticancer drugs. Enzymatic degradation of chitosan and HP-chitosan was first confirmed in vitro (using lysozyme) and in vivo by implanting both materials subcutaneously into the backs of rats. Then, using an in vitro dissolution test, we found that the release rate of uracil from chitosan membranes could be altered by the addition of HP-chitosan. Film- and stick-type implantable dosage forms of chitosan containing uracil were prepared by the 'Extrusion-in-Air' method. These gave rise to sustained release of uracil in vitro and in vivo. We conclude that chitosan and HP-chitosan have a potential as biocompatible and biodegradable vehicles in the preparation of implantable sustained release dosage forms of anticancer drugs.

Chemical Phenomena↗

PubMed1986

Comparison of the metabolism of diltiazem following percutaneous, subcutaneous, oral and intravenous administration.

The metabolism of diltiazem hydrochloride following percutaneous administration was compared with that following administration orally and by injection, to ascertain possible advantages in the percutaneous administration of ionizable, water-soluble drugs. The various routes of administration gave rise to markedly differing ratios of diltiazem and deacetylated diltiazem in plasma. The ratio of the AUC values for the two substances was 0.3 (intact skin) and 0.5 (stripped skin) following percutaneous administration, 0.2 following injection, and 0.8 following oral administration of diltiazem. Our results suggest that metabolism may be reduced in routes of administration that lead to very rapid drug absorption and/or rapid clearance from blood. HPLC chromatograms of plasma showed that the number and amounts of metabolites were less when diltiazem was given percutaneously rather than orally.

Administration, Cutaneous↗

PubMed1985