title: Effect of temperature on cyclodextrin production and characterization of paracetamol/cyclodextrin complexes.
abstract: 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.
  
  
  METHODS
  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 degrees C than at 80 degrees C. The catalytic efficiency (k(cat)/K(m)) of this enzyme indicated the higher value of the cyclization reaction at 60 degrees C compared to 80 degrees 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 alpha-, beta- and gamma-CD were A(N) type while that of paracetamol with maltosyl-beta-CD (G2-beta-CD) complex was A(L) type. The stability constants (K(c)) for the inclusion complex of paracetamol with alpha-, beta-, gamma-CD and G2-beta-CD were 5.69, 16.75, 4.73 and 2,223.25 M(-1), respectively.
  
  
  CONCLUSIONS
  The optimum temperature for CDs production was at 60 degrees C and the low solubility of paracetamol was significantly improved by complexation with CDs, where the enhancing effect was in the order of G2-beta-CD > beta-CD > alpha-CD > gamma-CD.
authors.affiliation: Department of Pre-Clinical Science (Biochemistry), Faculty of Medicine, Thammasat University, Pathumthanee, Thailand.
authors.forename: Jarunee
authors.initials: J
authors.lastname: Kaulpiboon
authors.forename: Prakarn
authors.initials: P
authors.lastname: Rudeekulthamrong
mesh_terms: D000082:Acetaminophen / Q000737:chemistry*; D018712:Analgesics, Non-Narcotic / Q000737:chemistry*; D058633:Antipyretics / Q000737:chemistry; D003500:Cyclization; D003505:Cyclodextrins / Q000032:analysis / Q000096:biosynthesis*; D004355:Drug Stability; D005964:Glucosyltransferases / Q000737:chemistry / Q000378:metabolism*; D006358:Hot Temperature; D012995:Solubility; D013213:Starch
chemical_list: D018712:Analgesics, Non-Narcotic; D058633:Antipyretics; D003505:Cyclodextrins; D000082:Acetaminophen; D013213:Starch; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase