Abstract
Aspirin continues to be one of the most useful analgesic anti inflammatory agents and new formulations are regularly produced in an attempt to overcome one of the major disadvantages of aspirin, namely, gastric irritation. A new aspirin formulation designed to minimize such irritation is the micro encapsulated aspirin, 'Levius'.
This product comprises small ethyl cellulose coated particles pressed into a tablet containing 500 mg of aspirin. The tablet allegedly disintegrates, releasing the particles from which the aspirin slowly diffuses. The absorption of 'Levius' was compared with that of an enteric coated aspirin. Absorption from the Levius preparation showed relatively little variation from subject to subject and gave levels similar to those achieved with other forms of sustained release aspirin. Levels reached a peak after approximately four hours, compared with the one hour to be anticipated with soluble aspirin. Absorption was much less consistent in the case of the enteric coated preparation: in three subjects, only very low blood levels were demonstrable over the first 12 hours after ingestion, and in one subject no salicylate could be detected. The pharmaceutical characteristics of different formulations of a given drug may substantially affect the blood concentrations attained. The results illustrate the extreme variability of absorption that may occur with enteric coated preparations.