title: Thermal and fractal analysis of diclofenac/Gelucire 50/13 microparticles obtained by ultrasound-assisted atomization.
abstract: The study describes the application of a spray-congealing technique, using a new ultrasound-assisted atomizer to prepare microparticles of diclofenac/Gelucire 50/13, with the aim to obtain a formulation of enhanced-release, at 10% w/w drug-to-excipient ratio, without any employ of solvent. Scanning electron microscopy showed that it was possible to obtain almost spherically shaped and non-aggregated microparticles; with good encapsulation efficiency (90% in most size fraction) and with a prevalent particle size in the range 150-350 mum. Image analysis results by SEM and the high fractal dimension value suggested that most particles have actually an ellipsoidal shape and a rather rough contour. Hot stage microscopy, differential scanning calorimetry, and X-ray powder diffractometry analysis were carried out to evaluate the nature of the solid state and the thermal behavior of the microparticles thus prepared. The in vitro tests displayed a significant increase of the diclofenac dissolution rate from ultrasound microparticles, compared with pure drug and with drug/Gelucire 50/13 physical mixtures.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Università di Bologna, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cavallari
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Rodriguez
authors.forename: Beatrice
authors.initials: B
authors.lastname: Albertini
authors.forename: Nadia
authors.initials: N
authors.lastname: Passerini
authors.forename: Francesca
authors.initials: F
authors.lastname: Rosetti
authors.forename: Adamo
authors.initials: A
authors.lastname: Fini
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D004008:Diclofenac / Q000737:chemistry*; D004055:Differential Thermal Analysis; D004339:Drug Compounding; D005079:Excipients; D005223:Fats / Q000737:chemistry*; D017709:Fractals; D007091:Image Processing, Computer-Assisted; D007202:Indicators and Reagents; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D009821:Oils / Q000737:chemistry*; D010316:Particle Size; D012995:Solubility; D014465:Ultrasonics; D014961:X-Ray Diffraction
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D005079:Excipients; D005223:Fats; D007202:Indicators and Reagents; D009821:Oils; C071184:Gelucire 50-13; D004008:Diclofenac