Preparation of Polymeric Nanoparticles by Polymerization of Monomers - Part 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.2219610

Phospholipid dry powders produced by spray drying processing: structural, thermodynamic and physical properties

Phospholipid particles for pharmaceutical applications were prepared by spray-drying processing and characterized for their structural, thermodynamic and physical properties. The lipid particles were spherical and potentially suitable for pulmonary applications (aerodynamic diameter less than 5 mum), for tablet preparations of orally administered drugs or as proliposomes in liquid formulations. The operational conditions, such as nozzle diameter, lipid concentration, flow rate and temperature of the feed solution, as well as the concentration of mannitol, the core material, were found to affect the particle properties, thus allowing them to be modified through the processing conditions. When mannitol was incorporated into formulations containing 20 or 45 mM lipid, at a feed flow rate of 3 ml/min, the resulting structures were more amorphous. More crystalline structures were obtained when the feed solution temperature and the nozzle diameter were increased from 25 to 60 degreesC and from 0.5 to I mm, respectively. The physical and chemical stability of the particles was preserved when they were stored under refrigeration, as shown by the water activity measurements and differential scanning calorimetry (DSC). These results show the potential of spray-dried particles for drug delivery applications. (C) 2004 Elsevier B.V. All rights reserved.145213914

Metabolic Effects of the Initial Glucose Concentration on Microbial Production of Hyaluronic Acid

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The objective of the present work was to evaluate the metabolic effects induced by the initial glucose concentration (IGC) on the cultivation of Streptococcus zooepidemicus for the production of hyaluronic acid (HA). These effects were monitored along non-controlled pH cultivations, carried out in 250-mL Erlenmeyer flasks (natural aeration) and in a 3-L bioreactor (forced aeration) as well. Effects of the IGC were observed with focus on the main metabolites, cell growth, production, and average molecular weight of HA. The absence of glucose resulted in a mixed acid metabolism independent of the oxygen supply, while, for IGCs ranging from 5 to 90 g L(-1), the homolactic metabolism was prevalent. The IGC had no influence on the amounts of either biomass or HA produced in the cultivations carried out in flasks; however, cultivations in 3-L bioreactor were found to be strongly dependent on it. The highest concentration of HA (1.21 g L(-1)) was obtained from 25 g L(-1) IGC, the only cultivation where the conversion of glucose to HA was higher than the one of glucose to biomass. Average molecular weight of HA increased concomitant with the IGC, independently of aeration; nevertheless, it decreased along cultivation under forced aeration, due to the shear imparted by stirring.162617511761Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Physical characterization of surface-modified liposomes by incorporation of gangliosides designed for immunotherapies

Surface-modified liposomes with gangliosides prolong their half life in blood stream that associated to the poor immunogenic properties of gangliosides are potentially useful for applications as immunotherapic vehicles. The physical characteristics of these biocolloids play an important role on their stability and exposition of the ganglioside antigens to the immunological system. The present work describes the physical characterization of liposomes incorporating a monosialoganglioside or a mixture of mono-, di- and trisialogangliosides. The liposomal matrix was composed of either dipalmitoylphosphatidylcholine and cholesterol, or in some preparations dihexadecylphosphate, which was added in order to provide a higher negative charge density on the liposome surface. Both types of liposomes were prepared by the dry phospholipids film hydration method and characterized by their phospholipid and ganglioside content, mean diameter, size distribution, morphology, membrane packing, lamellar structure and phase transition behavior. (C) 2004 Elsevier B.V. All rights reserved.2514169917518

Effects of soy peptone on the inoculum preparation of Streptococcus zooepidemicus for production of hyaluronic acid

Soy peptone (SP) was studied as nutrient source in replacement of the conventional media as Brain Heart Infusion (BHI) and sheep blood in the first seed culture medium in Petri plates of Streptococcus zooepidemicus. This substitution, aimed at meeting the claim of the pharmaceutical and cosmetics industries, for the removal of animal sources of the culture media used in obtaining their products for safety reasons. The animal sources were used as a control. The effects of this substitution were studied in fermentations carried out at 37 degrees C and 150 rpm in 250 mL Erlenmeyer flasks containing 100 mL culture medium containing glucose and SP only. The replacement of animal nutrient sources by SP to about twice the BHI concentration did not alter the amount of the produced HA, or caused deviations in the metabolism of the microorganism in favor of HA to the detriment of cell growth. (C) 2013 Elsevier Ltd. All rights reserved.130798800Cristali

Solid-State Fermentation for Humic Acids Production by a Trichoderma reesei Strain Using an Oil Palm Empty Fruit Bunch as the Substrate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Empty fruit bunch (EFB), an underutilized waste product of oil palm processing, was studied as a substrate for the production of humic acids (HA) by a Trichoderma reesei strain by solid-state fermentation (SSF) in Raimbault columns. HA have attracted the attention of many investigators due to their applications in agriculture, industry, the environment, and biomedicine. Commercial HA are currently chemically extracted from peat and coal, which are nonrenewable carbon sources. Biotechnological processes are important for their sustainable and controlled production, with SSF being especially promising for mimicking the natural habitat of fungi. Trichoderma sporulation and HA production are related, and the results of this study showed that SSF stimulated fast sporulation. The productivity related to HA was much higher than that of the biomass, indicating an efficient utilization of EFB. These findings, added to the low cost of EFB, make SSF an attractive process for HA production.172422052217Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Effects of Organic Solvents on Hyaluronic Acid Nanoparticles Obtained by Precipitation and Chemical Crosslinking

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Hyaluronic acid is a hydrophilic mucopolysaccharide composed of alternating units of D-glucuronic acid and N-acetylglucosamine. It is used in many medical, pharmaceutical, and cosmetic applications, as sponges, films, or particle formulations. Hyaluronic acid nanoparticles can be synthesized free of oil and surfactants by nanoprecipitation in organic solvents, followed by chemical crosslinking. The organic solvent plays an important role in particles size and structure. Therefore, this study aimed to investigate the influence of acetone, ethanol, and isopropyl alcohol on the synthesis and physico-chemical properties of hyaluronic acid nanoparticles. Particles were crosslinked with adipic hydrazide and chloride carbodiimide under controlled conditions. The nanoparticles obtained with all three studied solvents were moderately electrostatically stable. Experiments with acetone produced the smallest particle size (120.44 nm) and polydispersity (0.27). The size and polydispersity of hyaluronic acid nanoparticles correlated with the surface tension between water and the organic solvents, not with the thermodynamic affinity of water for the organic solvents.12328492857Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Hyaluronic acid depolymerization by ascorbate-redox effects on solid state cultivation of Streptococcus zooepidemicus in cashew apple fruit bagasse

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The cashew fruit (Anacardium occidentale L.) has been used as a promising agricultural resource for the production of low-molecular weight (M-W) hyaluronic acid (HA) (10(4)-10(5) Da). The cashew juice is a rich source of vitamin C containing, 1.2-2.0 g L-1. This work explores the effects of the initial concentration of the ascorbate on the solid fermentation of the juice-moisturized bagasse from the cashew apple fruit. The results show that the M-W reduction of HA is proportional to the initial ascorbate concentration. The presence of ascorbate did not influence the Streptococcus zooepidemicus metabolism. However, the HA productivity was increased from 0.18 to 0.28 mg g(-1) h(-1) when the ascorbate concentration ranged from 1.7 to 10 mg mL(-1). These findings contribute to the controlled production of HA in a low M-W range, which is important in cell signalization, angiogenesis and nanoparticles production.28522132219Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP