ISSN:
1573-904X
Keywords:
controlled-release pellets formulation
;
gamma scintigraphy
;
gastrointestinal transit time
;
isosorbide-5-nitrate
;
absorption rate
;
numerical deconvolution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract An oral formulation of controlled-release isosorbide-5-nitrate pellets has been used to investigate the location of pellets in the gastrointestinal (GI) tract and, in parallel, to measure the drug absorption from these locations. Using the method of gamma scintigraphy the transit times and spreading of pellets in the GI tract have been determined. The method of numeric deconvolution was applied to calculate the drug input into the systemic circulation. The results indicate that a well-absorbed substance such as isosorbide-5-nitrate is absorbed from the stomach and small intestinal in a manner that is controlled by the properties of the pellets. Drug absorption is reduced in the colon. The average transit time from mouth to colon is 6 to 8 hr, which represents the maximum acceptable time for drug release for this oral controlled-release preparation. Taking into account these relations an isosorbide-5-nitrate pellet formulation with a bioavailability of 84% has been developed that maintained the minimal therapeutic plasma level for more than 16 hr after application.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1016423404636
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