Effect of Temperature on Cyclodextrin Production and Characterization of Paracetamol/Cyclodextrin Complexes

Objective: To compare the effect of different reaction temperatures on the cyclization and coupling reactions of the Toruzyme® CGTase influencing the yield of cyclodextrins (CDs) and to study the solubility of paracetamol with CDs. Material and Method: Type and amount of CDs were analyzed by HPAEC-PAD. The stability constants for the inclusion complex formed between CDs and paracetamol were determined using the phase solubility method. The solubility of paracetamol with CDs was measured by UV-spectrophotometer at 240 nm. Results: The result has shown that the reaction temperature has effect on the Toruzyme ® CGTase reactions in production of CDs. The CDs yield after 30 min of incubation was higher at 60°C than at 80°C. The catalytic efficiency (kcat/Km) of this enzyme indicated the higher value of the cyclization reaction at 60°C compared to 80°C while the opposite was found for the coupling reaction. Paracetamol is used as an analgesic and antipyretic but it is poorly water-soluble drug. To improve the solubility of paracetamol, CDs obtained were used to study for paracetamol/CDs complexes. The phase-solubility diagrams of paracetamol with α-, β- and γ-CD were AN type while that of paracetamol with maltosyl-β-CD (G2-β-CD) complex was AL type. The stability constants (Kc) for the inclusion complex of paracetamol with α-, β-, γ-CD and G2-β-CD were 5.69, 16.75, 4.73 and 2,223.25 M-1, respectively. Conclusion: The optimum temperature for CDs production was at 60°C and the low solubility of paracetamol was signifi-cantly improved by complexation with CDs, where the enhancing effect was in the order of G2-β-CD> β-CD> α-CD> γ