In vitro echogenicity characterization of poly[lactide-coglycolide] (plga) microparticles and preliminary in vivo ultrasound enhancement study for ultrasound contrast agent application.
OBJECTIVE
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 mum) was acoustically characterized on a hydrodynamic device to select the most appropriate for ultrasound contrast agent application. Preparations of 3-microm 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-microm microparticles (3.26-microm mean diameter with 0.41-microm 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.


CONCLUSIONS
The 3-microm PLGA microparticles provided significant enhancement in vitro and in vivo without any toxicity.
Lavisse
Sonia
S
Département d'Imagerie et Laboratoire d'Imagerie du Petit Animal Laboratoire, Institut Gustave Roussy, Villejuif, France.
Paci
Angelo
A
Rouffiac
Valerie
V
Adotevi
Cecile
C
Opolon
Paule
P
Peronneau
Pierre
P
Bourget
Philippe
P
Roche
Alain
A
Perricaudet
Michel
M
Fattal
Elias
E
Lassau
Nathalie
N
D000818:Animals; D003287:Contrast Media; D066298:In Vitro Techniques; D019344:Lactic Acid; D008545:Melanoma / Q000000981:diagnostic imaging*; D051379:Mice; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D011134:Polysaccharides; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler
D003287:Contrast Media; D011108:Polymers; D011134:Polysaccharides; C059891:SHU 508; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid