169
plex, it led to a wide peak that started from 20 °C and ended
at 240 °C, while for the second, it also absorbed energy from
low temperatures; however, it gave an endothermic peak at
170 °C that resembles the one of lyophilized 2-HP-β-CD. This
suggests that an excess of crystalline cyclodextrin exists after
complexation in the case of losartan.
From all these observations, we can assume that the amount of
2-HP-β-CD necessary to complex losartan may be lower than 3.6
molecules for every molecule of drug, while for irbesartan, it seems
Fig. 3 The DSC thermograms of (a) 2-HP-β-CD raw material, (b) 2-HP-β-CD lyophilized, (c) irbesartan raw
material, (d) losartan raw material, (e) losartan lyophilized, (f) mixture of irbesartan raw material with
2-HP-β-CD raw material, (g) mixture of losartan raw material with 2-HP-β-CD raw material, (h) mixture of
irbesartan raw material with 2-HP-β-CD lyophilized, (i) mixture of losartan raw material with 2-HP-β-CD
lyophilized, (j) mixture of losartan lyophilized with 2-HP-β-CD raw material, (k) mixture of losartan lyophilized
with 2-HP-β-CD lyophilized, (l) lyophilized complex of irbesartan with 2-HP-β-CD, and (m) lyophilized complex
of losartan with 2-HP-β-CD
DSC on Sartan/Cyclodextrin Delivery Formulations
plex, it led to a wide peak that started from 20 °C and ended
at 240 °C, while for the second, it also absorbed energy from
low temperatures; however, it gave an endothermic peak at
170 °C that resembles the one of lyophilized 2-HP-β-CD. This
suggests that an excess of crystalline cyclodextrin exists after
complexation in the case of losartan.
From all these observations, we can assume that the amount of
2-HP-β-CD necessary to complex losartan may be lower than 3.6
molecules for every molecule of drug, while for irbesartan, it seems
Fig. 3 The DSC thermograms of (a) 2-HP-β-CD raw material, (b) 2-HP-β-CD lyophilized, (c) irbesartan raw
material, (d) losartan raw material, (e) losartan lyophilized, (f) mixture of irbesartan raw material with
2-HP-β-CD raw material, (g) mixture of losartan raw material with 2-HP-β-CD raw material, (h) mixture of
irbesartan raw material with 2-HP-β-CD lyophilized, (i) mixture of losartan raw material with 2-HP-β-CD
lyophilized, (j) mixture of losartan lyophilized with 2-HP-β-CD raw material, (k) mixture of losartan lyophilized
with 2-HP-β-CD lyophilized, (l) lyophilized complex of irbesartan with 2-HP-β-CD, and (m) lyophilized complex
of losartan with 2-HP-β-CD
DSC on Sartan/Cyclodextrin Delivery Formulations