Pulsed release of nitroglycerin from transdermal drug delivery systems.
To achieve a discontinuous drug delivery to the skin a new actively controlled transdermal system has been developed. The system consists of a tube shaped drug reservoir in combination with an electronic circuit and a gas producing cell. A magnetic switch was used to control the onset of the production of hydrogen gas. The gas was generated with a constant rate. The tube reservoir was filled with a solution of nitroglycerin in propylene glycol. A discontinuous distribution of nitroglycerin in the reservoir is responsible for the pulsed release. 2, 3, 4, or 6 fractions of nitroglycerin solution, which were separated from each other by sections with air, were filled into the tube reservoir. The release studies show that the release patterns directly reflect the number of doses, which were filled into the tube. A lag time of about 60 min was obtained, if the gas production is regulated by a 2.7 kOmega resistor. The drug is released during the pre-programmed time intervals within 6-7 h. Between the time intervals no drug release occurs.
Gröning
R
R
Institute for Pharmaceutical Technology, University of Münster, Corrensstr. 1, D-48149, Münster, Germany. groenin@uni-muenster.de
Kuhland
U
U
D000279:Administration, Cutaneous; D003692:Delayed-Action Preparations / Q000493:pharmacokinetics*; D016503:Drug Delivery Systems / Q000379:methods*; D005740:Gases / Q000138:chemical synthesis; D005996:Nitroglycerin / Q000493:pharmacokinetics*; D019946:Propylene Glycol; D011673:Pulsatile Flow; D013997:Time Factors
D003692:Delayed-Action Preparations; D005740:Gases; D019946:Propylene Glycol; D005996:Nitroglycerin