title: Solid state manipulation of lornoxicam for cocrystals--physicochemical characterization.
abstract: BACKGROUND
  Lornoxicam is an analgesic and anti-inflammatory drug of choice and belongs to Class II (low solubility) of BCS (Biopharmaceutical Classification System). Thus bioavailabilities problems are predominant.
  
  
  OBJECTIVE
  Through crystal engineering approach, a method was developed for obtaining multi-component cocrystals of lornoxicam using pharmaceutically acceptable compounds as guests.
  
  
  METHODS
  Lornoxicam guest-free form was obtained from solution crystallization. Supramolecular synthon approach indicated that lornoxicam was in orthorhombic form. Further presence of intermolecular hydrogen bonding with layered structures was identified. Solvent drop grinding method permitted the formation of cocrystals of lornoxicam with catechol, resorcinol, benzoic acid, hydroxyquinone and 2,4 dihydroxy benzoic acid, all are capable of forming hydrogen bonding.
  
  
  CONCLUSIONS
  Lornoxicam cocrystals exhibited the difference in melting points and decomposition characteristics. The analysis of infrared (IR) indicated the shifting of characteristic bands of lornoxicam. The XPRD (X-Ray Powder Diffraction) pattern indicated the crystallinity of cocrystals and significant difference in 2θ value of intense peaks. Differential scanning calorimetry spectra of cocrystals denoted the changes in fusion endotherms, which are in agreements with melting points. The pH solubility profile of lornoxicam showed sigmoidal curve, which substantiated the pKa-dependent solubility. Lornoxicam cocrystals also exhibited a similar pH-solubility profile. Thus pairing of lornoxicam and coformers in the solution at high pH media was assumed. The in vitro dissolution studies of cocrystals were conducted at pH 4.0. The rapid rate of dissolution of cocrystals was observed in initial 10 min. The extent of dissolution was enhanced by 20% on account of cocrystallization.
  
  
  CONCLUSIONS
  The lornoxicam cocrystals were obtained with improved physicochemical characteristics.
authors.affiliation: Gokaraju Rangaraju College of Pharmacy, Department of Pharmaceutics, Osmania University, Hyderabad, India , and.
authors.forename: Monika
authors.initials: M
authors.lastname: Nijhawan
authors.forename: A
authors.initials: A
authors.lastname: Santhosh
authors.forename: P R Sathesh
authors.initials: PR
authors.lastname: Babu
authors.forename: C V S
authors.initials: CV
authors.lastname: Subrahmanyam
mesh_terms: D001682:Biological Availability; D002152:Calorimetry, Differential Scanning / Q000379:methods; D003460:Crystallization / Q000379:methods; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D010894:Piroxicam / Q000031:analogs & derivatives* / Q000737:chemistry; D033362:Powder Diffraction / Q000379:methods; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D044366:Transition Temperature; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D012996:Solutions; D010894:Piroxicam; C059451:lornoxicam
keywords: Catechol; cocrystals; dissolution; resorcinol; solubility; solvent drop grinding