PLA Nano‐ and Microparticles for Drug Delivery: An Overview of the Methods of Preparation

Abstract

The controlled release of medicaments remains the most convenient way of drug delivery. Therefore, a wide variety of reports can be found in the open literature dealing with drug delivery systems. In particular, the use of nano- and microparticles devices has received special attention during the past two decades. PLA and its copolymers with GA and/or PEG appear as the preferred substrates to fabricate these devices. The methods of fabrication of these particles will be reviewed in this article, describing in detail the experimental variables associated with each one with regard to the influence of them on the performance of the particles as drug carriers. An analysis of the relationship between the method of preparation and the kind of drug to encapsulate is also included. Furthermore, certain issues involved in the addition of other monomeric substrates than lactic acid to the particles formulation as well as novel devices, other than nano- and microparticles, will be discussed in the present work considering the published literature available.

Electrospraying, a Reproducible Method for Production of Polymeric Microspheres for Biomedical Applications

“…Ideally, these systems are also able to provide tailored release rates, required by certain therapies, by the control of particle morphology, size and polymeric matrix [4]. Importantly, such particles have the potential to minimize the propagation of drug payloads to non-targeted areas, limiting unwanted effects and allowing a site-specific delivery [1][2][3]5].…”

“…Several techniques have been presented in the literature for fabrication of polymeric nano-and microparticles, the most popular being based on emulsion techniques [5][6][7][8][9][10]. Molecules are dispersed or dissolved into a polymer solution and emulsified to form micro-droplets that are further dried after solvent removal [11].…”

Polysaccharide-Based Nanoparticles for Controlled Release Formulations

“…Nanoparticles are instantaneously formed during the fast diffusion of the polymer solution in the non-solvent. This technique has been up to date mainly applied for poly(lactic acid), poly(lactic-co-glycolic acid) (Lassalle & Ferreira, 2007) as well as for polysaccharide derivatives (Hornig & Heinze, 2008). Chitosan and amphiphilic cycodextrins are some examples of polysaccharide derivatives employed to obtain nanoparticles by this method.…”

Nova Estratégia De Preparação De Nanopartículas Lipídicas Sólidas Para Encapsulação De Compostos Hidrofílicos

“…Substâncias hidrofílicas e hidrofóbicas podem ser encapsuladas em nanopartículas poliméricas e lipídicas, contudo, a encapsulação de fármacos hidrofílicos com elevada eficiência ainda permanece um desafio, principalmente pela falta de afinidade entre o fármaco e o polímero (ou lipídio), geralmente lipofílico, e pela tendência do fármaco em migrar para a fase aquosa durante o processo de preparação, em especial aqueles de baixa massa molar (ALMEIDA; SOUTO, 2007;LASSALLE;FERREIRA, 2007;MÜLLER et al, 2000;RAO;GECKELER, 2011). Baseada nos princípios de duas técnicas bem estabelecidas para preparação de micronanopartículas lipídicas sólidas, a fusão-emulsificação e a dupla emulsificação, a técnica de fusão/dupla emulsificação tem demonstrado elevada eficácia na encapsulação de compostos hidrofílicos de alta massa molar em micropartículas lipídicas (BODMEIER et al, 1992;REITHMEIER et al, 2001), sendo bastante atrativa por sua formulação livre de solventes orgânicos.…”