Physicochemical properties of chitosan-lipid emulsions and their stability during the autoclaving process

Jumaa, Muhannad; Müller, Bernd W.

doi:10.1016/s0378-5173(99)00086-1

Cited by 71 publications

(26 citation statements)

References 23 publications

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“…It could be concluded that a decrease in the size of the particles in the emulsion tested was associated with increasing values of the negative Zeta potential. This observation concurs well with results previously reported for chitosan-lipid emulsions (a decrease in particle size followed by an increase in the positive Zeta potential) [20]. However, the obtained Zeta potential values might be changed during sterilization by autoclaving.…”

Section: Resultssupporting

confidence: 82%

Emulsions of oil from Adenanthera pavonina L. seeds and their protective effect

Jaromin

Żarnowski

Kozubek

2006

Cellular and Molecular Biology Letters

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Abstract:In our previous study, we developed very stable formulations of submicron oil-in-water emulsions from Adenanthera pavonina L. (family Leguminosae, subfamily Mimosoideae) seed oil, stabilised with soybean lecithin (SPC). Continuing our research, we introduced an additional co-emulsifier, Tween 80, to those formulations in order to decrease the size of the emulsion particles and improve their stability. Formulations with a mean particle size ranging from 43.6 to 306.5 nm and a negative surface charge from -45.3 to -28.5 mV were obtained. Our stability experiments also revealed that most of the tested formulations had a very good degree of stability over a 3-month storage period, both at 4ºC and at room temperature. Since many intravenous injectable drugs exhibit lytic activity against erythrocytes, we examined this activity for the emulsion form of cardol, a natural compound with already proven hemolytic properties. The incorporation of this agent into the emulsion caused an evident decrease in hemolytic activity (97-99%). This highly protective effect, observed against sheep erythrocytes, was independent of both the composition and the particle size of the emulsions used. Our studies suggest that nonionic surfactant/phospholipid-based emulsions containing this edible oil of A. pavonina L. may be useful as an alternative formulation matrix for pharmaceutical, nutritional or cosmetic applications of otherwise membrane-acting components.

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Section: Resultssupporting

confidence: 82%

Emulsions of oil from Adenanthera pavonina L. seeds and their protective effect

Jaromin

Żarnowski

Kozubek

2006

Cellular and Molecular Biology Letters

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“…30 Normalmente, a tonicidade de emulsões é ajustada com glicerol, 5 como observado nas Tabelas 1 e 2, apesar da existência de relatos de um potencial hemolítico superior para o glicerol, em relação ao sorbitol e xilitol. 61 Agentes iônicos e açúcares redutores (glicose), entretanto, podem interagir com proteínas, resultando em coloração marrom e/ou separação de fases da emulsão. 30 A adição de eletrólitos implica na interação com coloides estabilizados por repulsão eletrostática, podendo acarretar em limitações acerca da estabilidade do sistema.…”

Section: Fase Aquosaunclassified

Nanoemulsões como sistemas de liberação parenteral de fármacos

Bruxel¹,

Laux²,

Wild³

et al. 2012

Quím. Nova

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Recebido em 20/10/11; aceito em 29/3/12; publicado na web em 3/7/12 NANOEMULSIONS AS PARENTERAL DRUG DELIVERY SYSTEMS. Lipid nanoemulsions have recently been proposed as parenteral delivery systems for poorly-soluble drugs. These systems consist of nanoscale oil/water dispersions stabilized by an appropriate surfactant system in which the drug is incorporated into the oil core and/or adsorbed at the interface. This article reviews technological aspects of such nanosystems, including their composition, preparation methods, and physicochemical properties. From this review, it was possible to identify five groups of nanoemulsions based on their composition. Biopharmaceutical aspects of formulations containing some commercially available drugs (diazepam, propofol, dexamethasone, etomidate, flurbiprofen and prostaglandin E1) were then discussed.Keywords: emulsion; parenteral; drug. INTRODUÇÃOA solubilização de fármacos de reduzida hidrossolubilidade visando sua administração parenteral representa um grande desafio na área de desenvolvimento de medicamentos. Diversas estratégias são descritas na literatura para esta finalidade, incluindo a modificação do pH do veículo, a adição de cossolventes ou, ainda, a formação de complexos de inclusão com ciclodextrinas.1 Entretanto, limitações relacionadas à biocompatibilidade dos adjuvantes empregados, aos relatos de dor e de possível precipitação dos fármacos durante a administração podem ser considerados como fatores limitantes do uso destas abordagens. Neste contexto, sistemas nanoestruturados têm se mostrado promissores. Nanoemulsões lipídicas óleo em água têm sido empregadas há mais de 40 anos como fonte de calorias e ácidos graxos essenciais 2 e, mais recentemente, como sistemas de liberação de fármacos. A biocompatibilidade das matérias-primas empregadas para a sua obtenção (óleos de origem natural ou semissintética e fosfolipídeos) torna estes sistemas uma alternativa promissora para a administração de diversos tipos de moléculas.3 Nanoemulsões podem ser definidas como sistemas heterogêneos nos quais um líquido (a fase interna) é disperso em outro (a fase externa) na forma de gotículas, na presença de um agente emulsionante. Suas propriedades físico--químicas, influenciadas pela composição quali-e quantitativa e pelas condições de preparação, devem ser estritamente controladas, visando a administração por via parenteral e a estabilidade do sistema. 4,5 Existem na literatura algumas inconsistências relacionadas aos conceitos de nanoemulsões em relação às microemulsões. Apesar destes sistemas poderem apresentar características estruturais e visuais semelhantes em determinadas condições, diferenciam-se quanto a estabilidade termodinâmica. Contrariamente às nanoemulsões, as microemulsões são sistemas termodinamicamente estáveis. Entretanto, podem apresentar limitações para administração por via parenteral, pois suas propriedades são fortemente afetadas por alterações de temperatura e/ou diluições. Apesar da nomenclatura empregada, microemulsões apresentam geralmente tamanho...

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“…Jumaa and Müller developed a chitosan-lipid emulsion using a nonionic surfactant, pluronic F68. 26) They suggested that chitosan molecules localized at the interface of the oil droplets and intercalated with the nonionic surfactant. This may have occurred in our chitosan-coated emulsion as well.…”

Section: Resultsmentioning

confidence: 99%

Mucoadhesive Properties of Chitosan-Coated Ophthalmic Lipid Emulsion Containing Indomethacin in Tear Fluid

Yamaguchi

Ueda

Isowaki

et al. 2009

Biological & Pharmaceutical Bulletin

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The physical and biochemical barriers of the eye to topical instillation are tear flow drainage, corneal resistance to diffusion, enzymatic degradation in tears and cornea, and flow of aqueous humor. The ocular bioavailability of instilled drug is therefore extremely low for most ophthalmic solutions, and less than about 5% of the drug may reach the anterior chamber of the eye. 1) Usually, poorly soluble drugs are designed as ophthalmic suspensions. However, ocular bioavailability for ophthalmic suspensions is not good, similar to ophthalmic solutions. An ophthalmic lipid emulsion may improve the ocular bioavailability of poorly soluble or lipophilic drugs by increasing drug solubility in the oil droplet and enhancing drug penetration into intraocular tissues.2-4) Ophthalmic lipid emulsion is also promising with respect to its good tolerance, high stability, and ease of manufacturing.Usually, instilled particulate systems such as liposomes, nanoparticles, and lipid emulsions are rapidly eliminated from tear fluid. [5][6][7][8] Mucoadhesive polymers are therefore used to prolong the residence time of particulate carriers in tear fluid. Carbopol, hyaluronic acid, sodium carboxymethylcellulose, chitosan, and Thiomer are possible mucoadhesive polymers. Many researchers have reported that ocular bioavailability is improved and the residence time of drug in tear fluid prolonged with use of such polymers.9-11) Chitosan, a mucoadhesive polymer, is a cationic biopolymer which is generally obtained by alkaline deacetylation of chitin. It is biodegradable and biocompatible, and features excellent tolerance when administered topically onto the cornea.12) Its mucoadhesive properties are based on hydrogen bonding and electrostatic interaction between positive charges of amino groups in chitosan and the negative charges of sialic acid in mucin. Particulate systems coated with chitosan have been developed to improve the absorption of several drugs administered by one of the present authors. [13][14][15] When mucoadhesive particulate systems were instilled, these systems demonstrated significantly increased ocular bioavailability compared to normal formulations. [16][17][18] However, little is known concerning the pharmacokinetic profiles in tear fluid of instilled chitosan-coated particulate formulations. Additionally, little has been reported on ophthalmic lipid emulsions coated by chitosan to improve ocular bioavailability.In this study, we examined the effects of coating of ophthalmic lipid emulsion with chitosan on ocular bioavailability. Indomethacin was incorporated as a model drug in the oil droplets of the emulsions. It is an anti-inflammatory agent widely used for the treatment of post-operative inflammation after cataract surgery.19) The marketed eye drops containing it unfortunately exhibit poor bioavailability. 20) Thus, the objectives of this study were to evaluate the retention of chitosancoated emulsion in tear fluid, and then to compare the ocular bioavailability of this formulation with non-coated emulsion. We ...

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Physicochemical properties of chitosan-lipid emulsions and their stability during the autoclaving process

Cited by 71 publications

References 23 publications

Emulsions of oil from Adenanthera pavonina L. seeds and their protective effect

Emulsions of oil from Adenanthera pavonina L. seeds and their protective effect

Nanoemulsões como sistemas de liberação parenteral de fármacos

Mucoadhesive Properties of Chitosan-Coated Ophthalmic Lipid Emulsion Containing Indomethacin in Tear Fluid

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