Coatings from blends of Eudragit® RL and L55: A novel approach in pH-controlled drug release

Wulff, Robert; Leopold, Claudia

doi:10.1016/j.ijpharm.2014.09.023

Cited by 27 publications

(14 citation statements)

References 37 publications

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“…The differences in the drug permeability of these coatings that have been reported by Wulff and Leopold (26) could not be correlated to the presented differences in their swelling behavior. Only the 4:1 blend in phosphate buffer leads to a different result with extensive swelling within 24 h.…”

Section: Investigation Of the Swelling Behavior Of Plain Copolymer Fimentioning

confidence: 56%

“…For theophylline pellets coated with the 4:1 copolymer blend, a long lag time followed by fast drug release has been reported (26). This lag time can be explained with the decreased extent of ion exchange that might have decreased the drug release rate in the initial phase as discussed above.…”

Section: Investigation Of the Swelling Behavior Of Plain Copolymer Fimentioning

confidence: 91%

“…Moreover, previous studies have reported an altered polymer swelling behavior as a result of ionic interactions between oppositely charged coating polymers and consequently an altered drug release behavior (19,32). Moreover, the drug permeability of RL:L55 coating blends is generally lower in phosphate buffer pH 6.8 than in hydrochloric acid pH 1.2 (26). The most unusual RL:L55 copolymer with regard to its release behavior was the 4:1 blend.…”

Section: Investigation Of the Swelling Behavior Of Plain Copolymer Fimentioning

confidence: 92%

“…50°C) and Eudragit ® L55 (methacrylic acid-ethyl acrylate copolymer, glass transition temperature approx. 110°C) from organic solution (11,26). The structures of these copolymers are shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Coatings of Eudragit® RL and L-55 Blends: Investigations on the Drug Release Mechanism

Wulff

Leopold

2015

AAPS PharmSciTech

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Abstract. In a previous study, generally lower drug release rates from RL:L55 blend coated pellets in neutral/basic release media than in acidic release media were reported. The aim of this study was to obtain information on the drug release mechanism of solid dosage forms coated with blends of Eudragit ® RL (RL) and Eudragit ® L-55 (L55). Swelling experiments with free films were analyzed spectroscopically and gravimetrically to identify the physicochemical cause for this release behavior. With Raman spectroscopy, the swelling of copolymer films could be monitored. IR spectroscopic investigations on RL:L55 blends immersed in media at pH 6.8 confirmed the formation of interpolyelectrolyte complexes (IPECs) that were not detectable after swelling in hydrochloric acid pH 1.2. Further investigations revealed that these IPECs decreased the extent of ion exchange between the quaternary ammonium groups of RL and the swelling media. This is presumably the reason for the previously reported decreased drug permeability of RL:L55 coatings in neutral/basic media as ion exchange is the determining factor in drug release from RL coated dosage forms. Gravimetric erosion studies confirmed that L55 was not leached out of the film blends during swelling in phosphate buffer pH 6.8. In contrast to all other investigated films, the 4:1 (RL:L55) blend showed an extensive swelling within 24 h at pH 6.8 which explains the reported sigmoidal release behavior of 4:1 blend coated pellets. These results help to understand the release behavior of RL:L55 blend coated solid dosage forms.KEY WORDS: enteric polymethacrylate; interpolyelectrolyte complex; ion exchange; polymer blend; quaternary polymethacrylate.

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Section: Investigation Of the Swelling Behavior Of Plain Copolymer Fimentioning

confidence: 56%

Section: Investigation Of the Swelling Behavior Of Plain Copolymer Fimentioning

confidence: 91%

Section: Investigation Of the Swelling Behavior Of Plain Copolymer Fimentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Coatings of Eudragit® RL and L-55 Blends: Investigations on the Drug Release Mechanism

Wulff

Leopold

2015

AAPS PharmSciTech

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“…Nos resultados de índice de polidispersão observou-se que os valores da formulação NC-EUD-A foi mais elevado, indicando baixa homogeneidade do sistema. O polímero EUD RL100 apresenta características catiônicas decorrentes do grupo amônio quaternário presente em sua estrutura, o que justifica o potencial zeta positivo encontrado nas análises 35 . Quanto ao pH das suspensões de nanocápsulas, foram observados valores levemente ácidos.…”

Section: Sistemas Nanoestruturados Contendo óLeo De Linhaça: Desenvolunclassified

Sistemas Nanoestruturados Contendo Óleo De Linhaça: Desenvolvimento Tecnológico E Caracterização Físico-Química De Nanoemulsões E Nanocápsulas Poliméricas

Rigon¹,

Giuliani²,

Stangarlin³

et al. 2017

Saúde (Sta. Maria)

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Objetivo: O óleo de linhaça apresenta diversas propriedades terapêuticas, principalmente devido à presença de ácidos poli-insaturados em sua composição. Para melhor eficácia e/ou aumento da estabilidade de óleos vegetais farmacologicamente ativos, sistemas nanoestruturados são desenvolvidos para veiculação deste tipo de substância. Este estudo objetivou desenvolver e caracterizar sistemas nanoestruturados contendo óleo de linhaça. Foram preparadas nanocápsulas poliméricas e nanoemulsões, avaliando-se duas concentrações de óleo (1,5% e 3,0%) em ambas as formulações e dois polímeros, Poli(ε-caprolactona) e Eudragit ® RL100, no desenvolvimento das nanocápsulas. Ambas as formulações apresentaram características adequadas para sistemas coloidais. Em relação às nanoemulsões, houve diferença significativa das características entre as quantidades de óleo, sendo que 1,5% de óleo de linhaça foi a concentração mais satisfatória. Em relação à presença dos polímeros, houve variação apenas dos valores de potencial zeta e pH. Concluindo, as formulações foram consideradas adequadas para o encapsulamento do óleo de linhaça, sendo carreadores promissores para outras substâncias ativas.Descritores: Óleos Vegetais; Óleo de Linhaça; Nanoemulsões: Nanocápsulas Poliméricas. Cristina ABSTRACTObjective: Linseed oil has several therapeutic properties, mainly due to the presence of polyunsaturated acids in its composition. For best efficiency and/or increasing the stability of vegetable oils pharmacologically active, nanoestructured systems are developed to vehicle this type of substance. This study aimed to develop and characterize nanostructured systems containing linseed oil. Polymeric nanocapsules, and nanoemulsions were prepared, evaluating two oil concentrations (1.5% and 3.0%) in both formulations and two polymers, Poli(ε-caprolactona) e Eudragit ® RL100, of the nanocapsules development. Both formulations showed appropriate properties for colloidal systems. Regarding the nanoemulsions, there was a significant difference in characteristics between the amounts of oil, while 1.5% linseed oil was the most satisfying concentration. About presence of polymers, there was variation only of zeta potential and pH values. In conclusion, the formulations were considered suitable for the encapsulation of the linseed oil, being promising carriers for other active substances.

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Drug loading strategy of modular self‐assembly mode: Curcumin pyrimidine derivatives mediated by pH‐sensitive materials

Feng,

Wang,

Liu

et al. 2024

Journal of Polymer Science

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Chemotherapy drugs often cause various adverse reactions and affect normal tissues, so it is of great significance to design effective targeted anti‐tumor drug delivery methods. We constructed a series of self‐assembled supramolecular modular structures and explored whether they could become an effective targeted antitumor fluorescent agent. UV and fluorescence spectra show that it has fluorescence. The drug release curve was determined by dialysis method and the results showed that the release rate of PCB series composites was the highest under pH = 5. The curcumin pyrimidine derivative was embedded in the structure, and the formation of the complex was confirmed by infrared spectroscopy. The results for the cell imaging indicated that with the decrease of environmental pH value, the ability of PCB‐1 and PCB‐2 to penetrate the biofilm barrier into cells increased, suggesting that they have targeting action. The results of the cell viability test showed that PCB‐1 and PCB‐2 had a good inhibitory effect on MGC and HeLa cells. TEM showed that PCB‐1 was a regular hexahedron structure and PCB‐2 was a rod structure. In addition, the encapsulation efficiency of PCB‐1 and PCB‐2 was tested to be 86.50% and 88.57%, respectively, with drug loading rates of 27.62% and 28.38%, and Zeta potential values of +35 and +32. In conclusion, PCB‐1 and PCB‐2 are good potential anti‐tumor fluorescent agents.

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Coatings from blends of Eudragit® RL and L55: A novel approach in pH-controlled drug release

Cited by 27 publications

References 37 publications

Coatings of Eudragit® RL and L-55 Blends: Investigations on the Drug Release Mechanism

Coatings of Eudragit® RL and L-55 Blends: Investigations on the Drug Release Mechanism

Sistemas Nanoestruturados Contendo Óleo De Linhaça: Desenvolvimento Tecnológico E Caracterização Físico-Química De Nanoemulsões E Nanocápsulas Poliméricas

Drug loading strategy of modular self‐assembly mode: Curcumin pyrimidine derivatives mediated by pH‐sensitive materials

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