Original ArticleIn Vitro Echogenicity Characterization of Poly[lactide-coglycolide] (PLGA) Microparticles and Preliminary In Vivo Ultrasound Enhancement Study for Ultrasound Contrast Agent ApplicationLavisse, Sonia*†; Paci, Angelo PharmD, PhD‡; Rouffiac, Valerie PhD*; Adotevi, Cecile PharmD§; Opolon, Paule MD†; Peronneau, Pierre PhD*; Bourget, Philippe PharmD, PhD‡; Roche, Alain MD*; Perricaudet, Michel PhD†; Fattal, Elias PharmD, PhD§; Lassau, Nathalie MD, PhD*Author Information From the *Département d'Imagerie et Laboratoire d'Imagerie du Petit Animal Laboratoire, Institut Gustave Roussy, Villejuif; †Laboratoire de Vectorologie et Transfert de gènes, UMR CNRS 8121, Institut Gustave Roussy, Villejuif; ‡Département de Pharmacie Clinique, Institut Gustave Roussy, Villejuif; and §Laboratoire de Physicochimie-Pharmacotechnie-Biopharmacie, Chtāenay-Malabry, France. Received January 27, 2005 and accepted for publication, after revision, March 27, 2005. Supported by the Région Ile de France and the Paris XI University. Reprints: Nathalie Lassau, MD, PhD, Département d'Imagerie. Institut Gustave-Roussy, 39, avenue Camille Desmoulins, 94805 Villejuif Cedex, France. E-mail: [email protected]. Investigative Radiology: August 2005 - Volume 40 - Issue 8 - p 536-544 doi: 10.1097/01.rli.0000170818.03210.ee Buy Metrics Abstract Objectives: This work includes (1) the characterization of a reproducible poly[lactide-coglycolide] (PLGA) microparticle preparation with an optimial mean diameter and size distribution and (2) the preliminary in vivo ultrasonographic investigation of PLGA microparticles. Methods: A first series of PLGA microparticle preparations (1 to 15 μm) was acoustically characterized on a hydrodynamic device to select the most appropriate for ultrasound contrast agent application. Preparations of 3-μm microparticles were selected, characterized at different doses, and then injected into 20 melanoma grafted mice for contrast-enhanced power Doppler ultrasonography evaluation. Results: The 3-μm microparticles (3.26-μm mean diameter with 0.41-μm standard deviation) led to in vitro enhancement of 18.3 dB at 0.62 mg/mL. In vivo experiments showed 47% enhancement of intratumoral vascularization detection after PLGA injection, significantly correlated (P < 0.0001) with preinjection intravascularization and tumoral volume. No toxicity was histologically observed. Conclusion: The 3-μm PLGA microparticles provided significant enhancement in vitro and in vivo without any toxicity. © 2005 Lippincott Williams & Wilkins, Inc.