title: Investigation of the effect of hydroxypropyl methylcellulose on the phase transformation and release profiles of carbamazepine-nicotinamide cocrystal.
abstract: OBJECTIVE
  The aim of this work was to investigate the influence of hydroxypropyl methylcellulose (HPMC) on the phase transformation and release profile of carbamazepine-nicotinamide (CBZ-NIC) cocrystal in solution and in sustained release matrix tablets.
  
  
  METHODS
  The polymorphic transitions of the CBZ-NIC cocrystal and its crystalline properties were examined by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Raman spectroscopy, and scanning electron microscopy (SEM).
  
  
  RESULTS
  The apparent CBZ solubility and dissolution rate of CBZ-NIC cocrystal were constant in different concentrations of HPMC solutions. In a lower percentage of HPMC in the matrix tablets, the CBZ release profile of the CBZ-NIC cocrystal was nonlinear and declined over time. With an increased HPMC content in the tablets, the CBZ-NIC cocrystal formulation showed a significantly higher CBZ release rate in comparison with the other two formulations of CBZ III and the physical mixture.
  
  
  CONCLUSIONS
  Because of a significantly improved dissolution rate of the CBZ-NIC cocrystal, the rate of CBZ entering into solution is significantly faster than the rate of formation of the CBZ-HPMC soluble complex in solution, leading to a higher supersaturation level of CBZ and subsequently precipitation of CBZ dihydrate.
authors.affiliation: School of Pharmacy, De Montfort University, Leicester, Leicester, LE1 9BH, UK, mli@dmu.ac.uk.
authors.forename: Mingzhong
authors.initials: M
authors.lastname: Li
authors.forename: Shi
authors.initials: S
authors.lastname: Qiu
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Lai
authors.forename: Mohammad
authors.initials: M
authors.lastname: Rehan
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage* / Q000737:chemistry; D002220:Carbamazepine / Q000008:administration & dosage* / Q000737:chemistry; D003460:Crystallization; D003692:Delayed-Action Preparations / Q000737:chemistry*; D065347:Hypromellose Derivatives / Q000737:chemistry*; D009536:Niacinamide / Q000008:administration & dosage* / Q000737:chemistry; D044367:Phase Transition; D033362:Powder Diffraction; D012995:Solubility; D013607:Tablets; D014803:Vitamin B Complex / Q000008:administration & dosage* / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D018712:Analgesics, Non-Narcotic; D003692:Delayed-Action Preparations; D013607:Tablets; D014803:Vitamin B Complex; D009536:Niacinamide; D002220:Carbamazepine; D065347:Hypromellose Derivatives