Modelling of Theophylline Compound Release from Hard Gelatin Capsules Containing Gelucire Matrix Granules

Hard shell capsules containing four theophylline compounds of different solubilities (theophylline, etofylline, diprophylline and proxyphylline) were prepared with saturated polyglycolysed glycerides (Gelucires) of melting point above 45°C and HLB value below 10. A polyvalent formulation was obtained after granulation by melting and congealing and use of glyceryl behenate (Compritol) as a lubricant of the solidified suspensions. The best yields of granulation were obtained with Gelucires 64/02, 54/02 and 50/02. The influence of three parameters was studied: melting point and HLB of the Gelucires, as well as drug solubility. Drug release was found to increase as the melting point decreased and as HLB dnd drug solubility rose. Theophylline showed abnormal behaviour because