Proteins and peptides: non-invasive delivery

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Development of innovative nanotechnology-based drug delivery systems for cancer therapy

Controlled drug delivery systems are not a new subject in the biomedical field. The continuously increasing need for the improvement of health care services has been the driving force for both search and development of such systems. Among these, micro- and nano-sized vehicles (e.g. nanocapsules, liposomes and mixed micelles) have received special attention over the last decade; they have been used for the delivery and vectorization of many pharmacologically active molecules, as is the case of anti-neoplastic drugs.Os sistemas de libertação controlada de fármacos não são uma temática recente na área das ciências biomédicas: a crescente exigência no sector dos cuidados de saúde despoletou o desenvolvimento desta área científica. De entre os vários tipos de sistemas propostos, as micro- e nano-estruturas (i.e., nanocápsulas, lipossomas e micelas mistas) têm recebido especial atenção por parte dos investigadores ao longo da última década, tendo sido desenvolvidos sistemas de libertação e vectorização de muitas moléculas farmacologicamente activas, nomeadamente de fármacos anti-neoplásicos.info:eu-repo/semantics/publishedVersio

Interesterification and acidolysis of butterfat with oleic acid by Mucor javanicus lipase: changes in the pool of fatty acid residues

Lipases have become powerful tools in the manufacture of structured fats either via randomization of their glyceride composition or incorporation of externally supplied fatty acid residues in such glycerides. The present communication reports on changes that occurred in the fatty acid pool of anhydrous butterfat subject to interesterification and to acidolysis with oleic acid catalyzed by a commercial lipase immobilized by plain physical adsorption onto hydrophobic hollow fibers at 40°C under controlled water activity. The main goal of this research effort was to engineer butterfat so as to increase its level of unsaturated fatty acid residues and concomitantly decrease its level of medium- and long-chain saturated fatty acid residues (viz. lauric and myristic acids). Although a certain degree of net hydrolysis of butterfat was observed, the triacylglycerols of butterfat subject to acidolysis were found to possess more (approximately 30% w/w) oleic acid and significantly less (8% w/w) lauric acid and less (2% w/w) myristic acid than those of the original butterfat

On the performance of a hollow-fiber bioreactor for acidolysis catalyzed by immobilized lipase

The present communication describes the chemical modification of anhydrous butterfat by interesterification with oleic acid catalyzed by a lipase of Mucor javanicus. Two reactor configurations were tested, a batch-stirred tank reactor containing suspended lipase and a batch-stirred tank reactor in combination with a hollow-fiber membrane module containing adsorbed lipase. The goal of this research was to assess the advantage of using a (hydrophobic) porous support to immobilize the lipase in attempts to engineer butterfat with increased levels of unsaturated fatty acid residues (oleic acid) at the expense of medium-to-long chain saturated fatty acids (myristic and palmitic acids). Reactions were carried out at 40°C in the absence of solvent under controlled water activity, and were monitored by chromatographic assays for free fatty acids. The results obtained indicate that the rate of interesterification using the proposed reactor configuration is enhanced by a factor above 100 relative to that using suspended lipase, for the same protein mass basis. Although hydrolysis of butterfat occurred to some degree, the enzymatic process that uses the hollow-fiber reactor was technically superior to the stirred tank system

Lipase-catalyzed modification of butterfat via acidolysis with oleic acid

During the last decade increased interest in reactions catalyzed by lipases from various microbial sources has prompted attempts to rationally design lipases and lipase-catalyzed processes aiming at modification of functional properties of oils and fats. The present communication reports experimental work on the chemical modification of anhydrous butterfat via interesterification reactions with oleic acid catalyzed by a commercial lipase immobilized by plain physical adsorption on a bundle of hydrophobic hollow fibers. The main goal of this research effort was to engineer butterfat so as to increase its level of unsaturated fatty acid residues (viz. oleic acid) and concomitantly decrease its level of medium-to-long chain saturated fatty acid residues (viz. myristic and palmitic acids). All reactions were carried out at 40 °C in the absence of any solvent but under controlled water activity, and their extent was monitored via Chromatographic assays for free fatty acids. Although a certain degree of net hydrolysis of butterfat was observed, the enzymatic process studied was technically feasible and able to reach the predefined goals

Lipase catalyzed modification of milkfat

Decreasing consumption of high fat milk and dairy products is driving the dairy industry to seek other uses for increasing surplus of milkfat. Enzyme catalyzed modification of milkfat using lipases is receiving particular attention. This review examines lipase-mediated modification of milkfat. Especial attention is given to industrial applications of lipases for producing structured and modified milkfat for improved physical properties and digestibility, reduced caloric value, and flavor enhancement. Features associated with reactions such as hydrolysis, transesterification, alcoholysis and acidolysis are presented with emphasis on industrial feasibility, marketability and environmental concerns. Future prospects for enzyme catalyzed modification of milk fat are discussed

Stability of a commercial lipase from Mucor javanicus: kinetic modeling of pH and temperature dependencies

The present communication reports experimental and modelling work pertaining to the independent roles of pH and temperature on deactivation of a crude lipase from Mucor javanicus. Experimental data oflipolytic activities were generated by a classic pH-stat assay on a triolein emulsion following incubation at several pH values for a fixed time, or at several temperatures for various times; postulated models were then fitted by nonlinear fitting to such data. The pH-dependence data were best fit by assumption of three forms of enzyme with increasing states of protonation, with pKa values of 6.2 and 11.3, respectively, where only the intermediate form is stable within the time frame considered. The thermal-dependence data were best fit by assumption of parallel steps of deactivation and rearrangement, with activation energies of 228.8 and 221.7 kJ mol~l, respectively

Evolution of free fatty acid profile during ripening in cheeses manufactured from bovine, ovine and caprine milks with extracts of Cynara cardunculus as coagulant

Changes in the concentrations of free fatty acids (FFA) in bovine, ovine and caprine milk cheeses manufactured with a plant rennet (flowers of Cynara cardunculus) were studied throughout a 68-day ripening period. The long-chain saturated (C16 : 0 and C18 : 0) and unsaturated (C18 : 1, C18 : 2, and C18 : 3) FFA were the most abundant at all stages of ripening. The overall concentration of FFA in fresh cheese was 3598, 3538 and 3868 mg/kg cheese for bovine, ovine and caprine milk cheeses, respectively; these values increased to 5047, 6517 and 5257 mg/kg cheese, respectively, by 68 days, of which 1171, 1734 and 1791 mg/kg cheese, respectively, were accounted for by C4 : 0 – C12 : 0. The FFA that showed the highest fractional increase by 68 days of ripening in bovine milk cheese were C4 : 0, C6 : 0, C8 : 0, C12 : 0, C18 : 1 and C18 : 2; in ovine milk cheese they were C4 : 0, C6 : 0, C8 : 0, C10 : 0, C14 : 0, and C18 : 1; and in caprine milk cheese they were C4 : 0, C8 : 0, C10 : 0, C14 : 0 and C18 : 1

The role of lipids in drug absorption throught the GIT

Os vectores lipídicos apresentam inúmeras vantagens para a administração oral de substâncias farmacológicas, p.ex. são compostos por moléculas lipídicas semelhantes àquelas que figuram nos tecidos humanos, tornando-se biocompatíveis, biotoleráveis e biodegradáveis. São exemplos as tradicionais emulsões O/A, as suspensões de nanopartículas lipídicas (SLNs e NLC s) e, recentemente, as SolEmuls®, que permitem localizar fármacos fracamente solúveis em ambas as fases das emulsões, na camada interfacial de lecitina. Este artigo aborda o papel dos lípidos no aumento da absorção e da biodisponibilidade de fármacos administrados oralmente. Lipid carriers show several advantages for oral delivery of pharmacologically active drugs, e.g. are composed of lipid molecules similar to those in human tissues, becoming therefore biocompatible, biotolerable and biodegradable. Examples include traditional o/w emulsions, suspensions of lipid nanoparticles (SLNs and NLC s) and, recently, the SolEmuls®, which allows localizing poorly soluble drug molecules both in oil and aqueous phases, in the interfacial layer of lecithin. This paper reports on the role of lipids in enhancing both drug absorption and bioavailability when administered orally