Thermogravimetric study of vinpocetine suppository

Introduction. Development of technology is the one of the main stage in creation of new medications. Technological process of suppository manufacturing includes sufficiently long thermoprocessing during suppository base making, addition of the active substances and homogenisation. This makes risk of chemical and physical transformations of active substances and excipients in suppository which can be destroyed and changed pharmacologicaly. Use of thermogravimetric analyses in pharmaceutical technology allows to study possibility of chemical interactions of components in the wide range of temperature. The aim of this work was to study thermoprocessing effects on suppository base with vinpocetine in temperature range of technological process of suppository manufacturing. Object. Vinpocetine rectal suppository (with 0,5% of surface-active substances), active substance (vinpocetine) and excipients (twin 80, cacao oil) were used as the objects of thermogravimetric investigation. Thermogravimetric analyses was carried out on the derivatograph «Shimadzu DTG-60» (Japan) with the platinum-rhodium thermocouple by heating from 25°C to 200°C in the aluminium crucible. α-Al2O3 was used as standard. Heating speed was 10ºС in minute. Model mass was 14,23 – 34,4 mg. Conclusions. It was established that cacao oil is thermolabile substance with melting temperature 41,32 ºС. Surface-active substance twin 80 displays thermostability from 30 tо 100ºС. Vinpocetine derivatogramme confirmed its thermostability in temperature range from 30 tо 154 ºС. Derivatogramme of vinpocetine rectal suppository 0,01 and suppository base displayed the absence of critical temperature lower 100ºС. Insignificant mass loss (0,21%) shows that fact. Investigation of composition over 100ºС wasn’t carried out because these temperatures aren’t used in technological process of suppository manufacturing. Presence of thermal effects on derivatogramme of vinpocetine rectal suppository coincides with thermal effects of suppository base. That indicates absence of chemical and physical transformations of active substance and excipients in application dosage form