Eliana B. Souto

Preparação de nanopartículas poliméricas a partir da polimerização de monômeros: parte I

Polymeric nanoparticles obtained from synthetic polymers such as copolymers of methacrylic acid, acrylic esters or metacrylics, have been widely used in pharmaceuticals for encapsulation of drugs. These nanoparticles have the advantages of drug protection, controlled release, improved bioavailability and lower toxicity, resulting in greater comfort to patients and compliance to the treatment. The production of nanoparticles (nanospheres and nanocapsules) by polymerization of monomers is reviewed and discussed in this article, highlighting the technological parameters that affect the physicochemical characteristics of nanoparticles, e.g. drug solubility, phase volume, pH of polymerization, molecular weight and monomer concentration, and the nature and concentration of the surfactant.

Preparação de nanopartículas poliméricas a partir de polímeros pré-formados: parte II

Nanoparticulas polimericas produzidas a partir de polimeros pre-formados, como os poliesteres alifaticos, tem sido amplamente utilizadas para incorporar, principalmente, principios ativos lipofilicos. A producao das nanoparticulas (nanocapsulas e nanosferas) por polimeros pre-formados pode ser realizada por emulsificacao-evaporacao do solvente, por deslocamento do solvente, por salting-out ou por emulsificacao-difusao do solvente. Estes metodos de producao estao revisados e descritos neste artigo, evidenciando os parâmetros tecnologicos que interferem nas caracteristicas fisico-quimicas das nanoparticulas, como a solubilidade do principio ativo, o volume e pH do meio de polimerizacao, a massa molar e concentracao do monomero e a natureza e concentracao do tensoativo.

Polímeros Sintéticos Biodegradáveis: Matérias-primas e Métodos de Produção de Micropartículas para uso em Drug Delivery e Liberação Controlada

Microparticles produced from synthetic polymers have been widely used in the pharmaceutical field for encapsulation of drugs. These microparticles show several advantages such as drug protection, mucoadhesion, gastro-resistance, improved bioavailability and increased patients compliance. In addition, it is possible to use lower amount of drug to achieve therapeutic efficiency with reduced local/systemic adverse side effects and low toxicity. Synthetic polymers used for the production of microparticles are classified as biodegradable or non-biodegradable, being the former more popular since these do not need to be removed after drug release. Production of polymeric microparticles can be used for encapsulation of hydrophilic and hydrophobic drugs, by emulsification following solvent extraction/evaporation, coacervation, methods that are revised in this paper, including advantages, disadvantages and viability of each methodology. Selection of methodology and synthetic polymer depends of the therapeutic purpose, as well as simplicity, reproducibility and possibility to scale up.

Intellectual Property and Nanopharmaceuticals

Nanopharmaceuticals are a promising pathway to overcome traditional therapeutic limitations, since they are formulated to have high affinity to a specific target. These formulations are an improvement of old formulations resulting in better patient compliance. To acquire commercialization rights over a formulation it is necessary to patent the invention. Patenting an invention is crucial for nanomedicine evolution. The significance of intellectual property in this field has led to many startup companies to patent their technology. Licensing agreements have been one of the important options for many entrepreneurs with suitable benefit to both the parties. Due to initiatives taken by government (like implementation of the Bayh Dole Act, in the USA), the industry-academia collaborative research activities have increased to a large extent.

Advances in antibiotic nanotherapy

Abstract Bacteria show resistance to antibiotic drugs through a variety of mechanisms. Moreover, the development of even new mechanisms of resistance have resulted in the simultaneous development of resistance to several antibiotic classes, creating very dangerous multidrug resistant (MDR) bacterial strains. However, when bacteria are drug resistant it does not mean that they stop responding to antibiotic, rather which occurs only at higher concentrations. Of greater concern are cases of acquired resistance, where initially susceptible populations of bacteria become resistant to an antibacterial drug, in particular antibiotics, and proliferate and spread under the selective use of that drug. One approach to address this challenge is to design drug analogs, which are already in clinical use and have activity against resistant organisms. However, bacteria are constantly succeeding to develop resistant mechanism to new antibiotic drugs, as well as to their analogs. The prevalent examples of such bacterial pathogens are vancomycin (Van) resistance by Enterococcus (VRE), MDR Pseudomonas aeruginosa , drug resistant nontyphoidal Salmonella , drug resistant Salmonella Typhi , drug resistant Shigella , methicillin-resistant Staphylococcus aureus (MRSA), drug resistant Streptococcus pneumonia , drug resistant tuberculosis. These bacterial pathogens cause severe illness. Threats in this category require monitoring and, in some cases, rapid incident or outbreak response. Therefore, there is an urgent need in developing new therapeutic approaches. Nanotechnology offers opportunities to re-explore the biological properties of already known antimicrobial compounds, such as antibiotics, by manipulating their size to change their effect. This review aims to discuss the antimicrobial resistance as a serious global health concern, clarifying microbial drug resistance mechanisms, and presenting evidence on how nanotechnology may be considered a tool against this issue.

Sol–Gel Carrier System: A Novel Controlled Drug Delivery

In the recent decades, numerous drug delivery systems based on nanoparticles have been developed. To deliver drugs to a specific site, many vehicles have been designed, including liposomes, lipid and polymeric nanoparticles. However these systems can suffer some limitations such as thermal and physical instability as well as opsonization by reticuloendothelial system. This chapter addresses the development and application of silica gel nanoparticles (nanogels) for drug delivery. The synthesis of nanoparticles by sol–gel technology offers new possibilities and many advantages for embedding organic compounds within silica, controlling their release from the host matrix into a surrounding medium, being a great potential for a variety of drug delivery applications, such as the site-specific delivery and intracellular controlled release of drugs, genes, and other therapeutic agents.