Development and in vitro evaluation of a controlled release formulation to produce wide dose interval morphine tablets

In this paper, a new pharmaceutical formulation for the administration of morphine has been developed. This system is based on a polymeric complex previously characterized. After the studies performed, it has been selected the following formulation: 62.5% of morphine complex, 15% of free morphine and 22.5% of Eudragit® RS. The morphine formulation proposed has been characterized by means of the study of the influence of several parameters such as pH, ionic strength, mean particle diameter of the components and total morphine dose by means of the tablet dimensions.This assayed formulation is able to provide a specific in vitro release profile that will be no influenced by possible variations in the GIT conditions. Moreover, this formulation can reproduce the same biopharmaceutical behaviour in an independent manner of the mean diameter particle of the components and the dimension of the tablet produced with several doses inside a wide interval of doses.