Biodegradable synthetic polymers: raw-materials and production methods of microparticles for drug delivery and controlled release

Micropartículas produzidas a partir de polímeros sintéticos têm sido amplamente utilizadas na área farmacêutica para encapsulação de princípios ativos. Essas micropartículas apresentam as vantagens de proteção do princípio ativo, mucoadesão e gastrorresistência, melhor biodisponibilidade e maior adesão do paciente ao tratamento. Além disso, utiliza menores quantidade de princípio ativo para obtenção do efeito terapêutico proporcionando diminuição dos efeitos adversos locais, sistêmicos e menor toxidade. Os polímeros sintéticos empregados na produção das micropartículas são classificados biodegradáveis ou não biodegradáveis, sendo os biodegradáveis mais utilizados por não necessitam ser removidos cirurgicamente após o término de sua ação. A produção das micropartículas poliméricas sintéticas para encapsulação tanto de ativos hidrofílicos quanto hidrofóbicos pode ser emulsificação por extração e/ou evaporação do solvente; coacervação; métodos mecânicos e estão revisados neste artigo evidenciando as vantagens, desvantagens e viabilidade de cada metodologia. A escolha da metodologia e do polímero sintético a serem empregados na produção desse sistema dependem da aplicação terapêutica requerida, bem como a simplicidade, reprodutibilidade e factibilidade do aumento de escala da produção2144286292COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR – CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO – FAPESPsem informaçãoMicroparticles 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 patient's 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

Correlations of visual scores, carcass traits, feed efficiency and retail product yield in Nellore cattle

The growing use of visual scores (VS) and ultrasound (US) for carcass evaluation in breeding programs, calls for a knowledge of the relationships between these traits and other relevant characteristics, such as feed efficiency and production of commercial cuts. The objective of this study was to evaluate correlations between body visual scores and carcass traits identified by ultrasound (US) and feed efficiency (FE), carcass weight (HCW), dressing percentage (DP) and retail product yield (RPY) in beef cattle. Nellore cattle (male), 42 non-castrated [NCAST] and 44 castrated [CAST]) were evaluated by both VS and US, at the postweaning (15-month old) and finishing phases (21-month old). Visual scores of conformation (C), precocity (P) and muscling (M) were assessed and the backfat thickness (UBFT), rump fat thickness (URFT) and ribeye area (UREA) were measured by ultrasound. Gain-to-feed (G:F) ratio and residual feed intake (RFI) were measured in feedlot. Hot carcass weight, DP and RPY were determined at harvest. Non-castrated cattle had greater HCW and RPY but lower UBFT and URFT than CAST. Postweaning VS and US were poorly correlated with FE in both sexual conditions. Finishing VS were negatively correlated with G:F in CAST and finishing URFT was negatively correlated with RPY in NCAST. The relationship of VS and US with feed efficiency and meat yield is affected by age at the date of evaluation and by castration. Feed efficiency is not related to the yield of meat cuts in Nellore cattl

Optimizing Sln And Nlc By 2 2 Full Factorial Design: Effect Of Homogenization Technique

Solid lipid nanoparticles (SLN) and nanostructured lipid carrier (NLC) have been employed in pharmaceutics and biomedical formulations. The present study focuses on the optimization of the production process of SLN and NLC by High Shear Homogenization (HSH) and High Pressure Homogenization (HPH). To build up the surface response charts, a 2 2 full factorial design based on 2 independent variables was used to obtain an optimized formulation. The effects of the production process on the mean particle size, polydispersity index (PI) and zeta potential (ZP) were investigated. Optimized SLN were produced applying 20,000 rpm HSH and 500 bar HPH pressure and NLC process 15,000 rpm HSH and 700 bar HPH pressure, respectively. This factorial design study has proven to be a useful tool in optimizing SLN (~ 100 nm) and NLC (~ 300 nm) formulations. The present results highlight the benefit of applying statistical designs in the preparation of lipid nanoparticles. © 2012 Elsevier B.V.32613751379Galindo-Rodriguez, S.A., Puel, F., Briancon, S., Allemann, E., Doelker, E., Fessi, H., (2005) Eur. J. Pharm. Sci., 25, pp. 357-367Gao, Y., Yang, R., Zhang, Z., Chen, L., Sun, Z., Li, Y., (2011) Nanotoxicology, 5, pp. 636-649Rawat, M.K., Jain, A., Singh, S., (2011) J. Pharm. Sci., 100, pp. 2366-2378Xie, S., Zhu, L., Dong, Z., Wang, X., Wang, Y., Li, X., Zhou, W., (2011) Colloids Surf., B, 83, pp. 382-387Kumar, V.V., Chandrasekar, D., Ramakrishna, S., Kishan, V., Rao, Y.M., Diwan, P.V., (2007) Int. J. Pharm., 335, pp. 167-175Pardeike, J., Hommoss, A., Muller, R.H., (2009) Int. J. Pharm., 366, pp. 170-184Souto, E.B., Muller, R.H., (2010) Handb. Exp. Pharmacol., pp. 115-141Bondi, M.L., Craparo, E.F., Giammona, G., Drago, F., (2010) Nanomedicine (Lond), 5, pp. 25-32Souto, E.B., Muller, R.H., (2006) J. Microencapsul., 23, pp. 377-388Ali, H., Shirode, A.B., Sylvester, P.W., Nazzal, S., (2009) Colloids Surf., A, 353, pp. 43-51Wissing, S.A., Kayser, O., Muller, R.H., (2004) Adv. Drug Deliv. Rev., 56, pp. 1257-1272Shegokar, R., Singh, K.K., Muller, R.H., (2011) Int. J. Pharm., 416, pp. 461-470Mehnert, W., Mader, K., (2001) Adv. Drug Deliv. Rev., 47, pp. 165-196Becker, R., Kruss, B., Muller, R.H., Peters, K., (1997), Patent, U. S., Ed.: Hamburg, DEMuchow, M., Maincent, P., Müller, R.H., (2008) Drug Dev. Ind. Pharm., 34, pp. 1394-1405Lippacher, A., Muller, R.H., Mader, K., (2001) Int. J. Pharm., 214, pp. 9-12Severino, P., Pinho, S.C., Souto, E.B., Santana, M.H., (2011) Colloids Surf., B, 86, pp. 125-130Luykx, D.M., Peters, R.J., Van Ruth, S.M., Bouwmeester, H., (2008) J. Agric. Food Chem., 56, pp. 8231-8247Deshiikan, S.R., Papadopoulos, K.D., (1998) Colloid Polym. Sci., 276, pp. 117-124Araujo, J., Gonzalez-Mira, E., Egea, M.A., Garcia, M.L., Souto, E.B., (2010) Int. J. Pharm., 393, pp. 167-175Abdelbary, G., Fahmy, R.H., (2009) AAPS PharmSciTech, 10, pp. 211-219Varshosaz, J., Minayian, M., Moazen, E., (2010) J. Liposome Res., 20, pp. 115-123Varshosaz, J., Ghaffari, S., Khoshayand, M.R., Atyabi, F., Azarmi, S., Kobarfard, F., (2010) J. Liposome Res., 20, pp. 97-104Feng, S., Huang, G., (2001) J. Control. Release, 71, pp. 53-69Souto, E.B., Wissing, S.A., Barbosa, C.M., Müller, R.H., (2005) Eur. J. Pharm. Biopharm., 58, pp. 83-90Liu, J., Hu, W., Chen, H., Ni, Q., Xu, H., Yang, X., (2007) Int. J. Pharm., 328, pp. 191-19

Preparation Of Polymeric Nanoparticles By Polymerization Of Monomers - Part I [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.22196100Nicolas, J., Couvreur, P., (2009) Rev. Nanomed. 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Enhancement Of The Oxygen Transfer In A Circulating Three-phase Fluidized Bed Bioreactor

The addition of α-alumina to the aqueous solution of sodium alginate for imobilization of viable cells allows the production of denser particles than the ones obtained with sodium alginate alone. This biocatalyst was used in the continuous oxidation of ethanol to acetic acid, by a strain of Acetobacter isolated from an ethanol plant. The continuous fermentation was carried out in a circulating three-phase fluidized bed bioreactor. Denser particles allow a greater oxygen transfer, resulting in increased volumetric production rate of acetic acid, because oxygen is usually the limiting factor of this process. The performance of the biocatalyst was analyzed in terms of respiration rate, oxygen diffusivity, volumetric mass-transfer coefficient, and global productivity. © 1993 Humana Press Inc.39-40145546