[A comparative study of properties of paracetamol tablets of the matrix type]. / Etude comparée des propriétés de comprimés de paracétamol de type matriciel.

Our study was to compare the quantitative and qualitative effects of 2 polymeric agents (méthylcellulose, hydroxypropylmethylcellulose) and of 2 diluants (lactose and dicalcic phosphate) on the compression properties and sustained liberation of acetaminophen matrixes. Three experimental plans were permitted the experimentation; regression equations were used for our analysis of the results. The results we obtained show the superiority importance of the effect of the diluant/acetaminophen ratio over the liberation of the drug, as well as the better efficiency of méthylcellulosic matrixes. Thence to its solubility, the lactose helps to a faster liberation.

[Application of the Weibull function to the study of in vivo/in vitro correlation]. / Application de la fonction de Weibull à l'étude des corrélations in vivo/in vitro.

After transformation of concentration-time curves by integration, the Weibull function is calculated, producing an equation for a derived function representing the plasma (or salivary) kinetics. This model can be employed in the analysis of in vivo/in vitro correlations, since cumulated dissolution percentages can be directly expressed as Weibull functions. A method was developed for prediction of salivary kinetics from in vitro dissolution data and the in vivo kinetics of a solution of the drug. This method was applied to results obtained for slow release formulations of acetaminophen and theophylline administered by the oral route.