EFFECT OF HUMIDITY AND PACKAGING ON THE LONG-TERM AGING OF COMMERCIAL SUSTAINED-RELEASE THEOPHYLLINE TABLETS

This paper discusses the influence of relative humidity and packaging on the dissolution rate of three commercial brands of theophylline controlled-release tablets, paying particular attention to the experimental design and data treatment. The reduction in the amount of theophylline released during an 8 h period after 3 years' storage varied depending on the product and storage conditions; the greatest reduction observed amounted to 41% of the original content. To interpret the data, a statistical model was used, based on the subdivision of the sum of the squares of the term 'treatments' from the variance analysis by orthogonal polynomials chosen in terms of the design of the storage conditions. In all instances, the factors responsible for the reduction could be indentified.