Lidocaine-loaded biodegradable nanospheres. I. Optimization of the drug incorporation into the polymer matrix

• Published in: Journal of controlled release Vol. 57; no. 3; pp. 259 - 268
• Main Authors: Görner, T, Gref, R, Michenot, D, Sommer, F, Tran, M.N, Dellacherie, E
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 22.02.1999; Elsevier
• Subjects: Anesthetics, Local - administration & dosage; Anesthetics, Local - chemistry; Biological and medical sciences; Chemistry, Pharmaceutical; Chromatography, Gel; Controlled release; Drug Delivery Systems; Encapsulation; General pharmacology; Kinetics; Lactic Acid; Lidocaine; Lidocaine - administration & dosage; Lidocaine - chemistry; Medical sciences; Microspheres; Molecular Weight; Nanoparticles; Particle Size; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Poly( d, l-lactic acid); Polyesters; Polymers; Solubility; Spectrophotometry, Ultraviolet; Surface Properties; Nanoparticles; Encapsulation; Poly( d, l-lactic acid); Lidocaine; Controlled release; Local anesthetic; Lactic acid polymer; Nanocapsule; Pharmaceutical technology; Controlled release form; Control release polymer; Dosage form; Drug carrier; Organic amide; In vitro; Release
• ISSN: 0168-3659; 1873-4995
• DOI: 10.1016/S0168-3659(98)00121-7

Spherical nanoparticulate drug carriers made of poly( d, l-lactic acid) with controlled size were designed. A local anesthetic, lidocaine, a small hydrophobic molecule, was incorporated in the core with loadings varying from about 7 to 32% (w/w) and increasing with the particle size. Particles with sizes from about 250 to 820 nm and low polydispersity were prepared with good reproducibility; the polymer concentration (at constant surfactant concentration) governed the particle size. The large particles with a high loading (∼30%) showed under in vitro conditions a slow release over 24–30 h, the medium sized carriers (loading of ∼13%) released the drug over about 15 h, whereas the small particles with small loading (∼7%) exhibited a rapid release over a couple of hours. It seems that the drug release rate is related to the state (crystallized or dispersed) of the drug incorporated in the polymer matrix.