title: Effect of cocrystallization techniques on compressional properties of caffeine/oxalic acid 2:1 cocrystal.
abstract: BACKGROUND
  Caffeine/oxalic acid 2:1 cocrystal exhibited superior stability to humidity over caffeine, but compressional behavior is not studied yet.
  
  
  OBJECTIVE
  To compare compressional properties of caffeine/oxalic acid 2:1 cocrystal obtained by different cocrystallization techniques.
  
  
  METHODS
  Cocrystal was obtained by solvent precipitation and ultrasound assisted solution cocrystallization (USSC) and characterized by X-ray powder diffraction and scanning electron microscopy. Compaction study was carried out at different compaction forces. Compact crushing strength, thickness and elastic recovery were determined.
  
  
  CONCLUSIONS
  Compaction was in order, caffeine > solvent precipitation cocrystal > USSC cocrystal. Caffeine exhibited sticking and lamination, where solvent precipitation compacts showed advantage. Caffeine and solvent precipitation compacts showed sudden drop in compactability, higher elastic recovery with severe lamination at 20,000 N. This was due to overcompaction. Crystal habit of two cocrystal products was same, but USSC cocrystals were difficult to compact. Uniform needle shaped USSC cocrystals must be difficult to orient in different direction and fracture during compression. Elastic recovery of USSC cocrystals was also more compared to other powders indicating less fracture and poor bonding between particles resulting in poor compaction.
  
  
  CONCLUSIONS
  Cocrystal formation did not improve compressional property of caffeine. Cocrystals exposed to different crystallization environments in two techniques may have resulted in generation of different surface properties presenting different compressional properties.
authors: Poona College of Pharmacy, Bharati Vidyapeeth University, Erandwane, Pune, India.
authors: Suyog
authors: S
authors: Aher
authors: Ravindra
authors: R
authors: Dhumal
authors: Kakasaheb
authors: K
authors: Mahadik
authors: Jarkko
authors: J
authors: Ketolainen
authors: Anant
authors: A
authors: Paradkar
mesh_terms: D002110:Caffeine / Q000737:chemistry*; D011232:Chemical Precipitation; D003460:Crystallization / Q000379:methods; D004339:Drug Compounding / Q000379:methods*; D004548:Elasticity; D008855:Microscopy, Electron, Scanning; D019815:Oxalic Acid / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013607:Tablets; D014463:Ultrasonography / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D012997:Solvents; D013607:Tablets; D002110:Caffeine; D019815:Oxalic Acid