The main purpose of our study
was to produce microspheres containing diltiazem hydrochloride and to perform
the thermoanalytical examination of the components and microspheres. Thermal
analysis is a very frequently used method in the preformulation tests of solid
dosage forms.
Diltiazem hydrochloride is a calcium-channel blocker
with short biological half life, so it is a potential candidate for sustained
or controlled release dosage forms.
Various techniques are available
for the microencapsulation of drugs. The technique of spray-drying was used
during our investigations.
It was found that the crystalline form
of the active agents could not be observed in the drug-loaded chitosan microspheres,
which indicates the molecular dispersion of the drug in the matrix. It was
established that the preparation conditions influenced the morphology and
size of the particles. Moreover, the sphericity of the microspheres was good.
On the basis of our investigations, the 1:1 diltiazem hydrochloride–chitosan
ratio is suggested as the best ratio.
Keywords chitosan - diltiazem hydrochloride - DSC - microspheres - TG