title: Impact of differential surface molecular environment on the interparticulate bonding strength of celecoxib crystal habits.
abstract: The present work investigates the impact of milling on differential compactibility behavior of celecoxib (CEL) crystal habits. Plate shaped (CEL-P) crystals showed better compactibility over acicular (CEL-A) crystals. Milling improved the compactibility of both the forms. However, despite similar particle shape, size, and surface area, milled fractions of the two habits showed significantly different interparticulate bonding strength. The greater bonding strength of milled CEL-P (MCEL-P) over milled CEL-A (MCEL-A) was attributed to the differential cleavage behavior of the two habits that conferred the different surface molecular environment to the milled powders. The preferred cleavage of CEL-P across {020} plane exposed the -CF3 group and the methyl phenyl ring on the surface of MCEL-P. On the other hand, CEL-A preferentially fractured along their shortest axis that increased the exposure of {100} plane on the surface of MCEL-A, which exposed the -CF3 group and the pyrazole ring. Surface free energy quantified by determining advancing contact angle revealed greater dispersive component of MCEL-P over MCEL-A. This is consistent with the differential cleavage behavior of CEL-P and CEL-A. This confirmed the role of dispersive component of surface free energy in governing interparticulate bonding strength of CEL. The study supports the postulate that tablet tensile strength is governed by the dispersive intermolecular interactions formed over the interparticulate bonding area.
authors.affiliation: Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S. A. S. Nagar, Mohali, Punjab, India.
authors.forename: Sameer R
authors.initials: SR
authors.lastname: Modi
authors.affiliation: Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S. A. S. Nagar, Mohali, Punjab, India.
authors.forename: Kailas S
authors.initials: KS
authors.lastname: Khomane
authors.affiliation: Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S. A. S. Nagar, Mohali, Punjab, India. Electronic address: akbansal@niper.ac.in.
authors.forename: Arvind K
authors.initials: AK
authors.lastname: Bansal
mesh_terms: D002152:Calorimetry, Differential Scanning; D000068579:Celecoxib; D003460:Crystallization; D052246:Cyclooxygenase 2 Inhibitors / Q000737:chemistry; D004339:Drug Compounding; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D016062:Porosity; D033362:Powder Diffraction; D011208:Powders; D011720:Pyrazoles / Q000737:chemistry*; D013449:Sulfonamides / Q000737:chemistry*; D013499:Surface Properties; D013607:Tablets; D013718:Tensile Strength; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D011208:Powders; D011720:Pyrazoles; D013449:Sulfonamides; D013607:Tablets; D000068579:Celecoxib
keywords: Bonding strength; Cleavage plane; Compactibility; Crystal habits; Milling; Surface anisotropy