Critical factors in the release of drugs from sustained release hydrophilic matrices

Maderuelo, Cristina; Zarzuelo, Aránzazu; Lanao, José M.

doi:10.1016/j.jconrel.2011.04.002

Cited by 436 publications

(274 citation statements)

References 167 publications

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“…Numerous varieties of pharmaceutical excipients are employed to improve or modulate tablet characteristics, among them methylcellulose (MC) and hypromellose (HPMC) are frequently used for controlling drug release from hydrophilic matrix systems (Ghori et al, 2014;Li et al, 2005;Maderuelo et al, 2011). These polymers are available in different grades varying in viscosity (molecular size), substitution ratios and particle size.…”

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confidence: 99%

Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen

Ghori

Šupuk

Conway

2014

European Journal of Pharmaceutical Sciences

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The pervasiveness of tribo-electric charge during pharmaceutical processing can lead to the exacerbation of a range of problems including segregation, content heterogeneity and particle surface adhesion. The excipients, hydroxypropyl methylcellulose (HPMC) and methylcellulose (MC), are often used in drug delivery systems and so it is important to understand the impact of associated factors on their charging and adhesion mechanisms, however, little work has been reported in this area. Such phenomena become more prominent when excipients are introduced to a powder mixture alongside the active pharmaceutical ingredient(s) (APIs) with inter-and intra-particulate interactions giving rise to electrification and surface adhesion of powder particles. The aim of this study was to understand the impact of material attributes (particle size, hydroxypropoxyl (Hpo) to methoxyl (Meo) ratio and molecular size) on the charging and adhesion characteristics of cellulose ethers. Furthermore, a poorly compactible and highly electrostatically charged drug, flurbiprofen, was used to develop binary powder mixtures having different polymer to drug ratios and the relationship between tribo-electric charging and surface adhesion was studied. Charge was induced on powder particles and measured using a custom built device based on a shaking concept, consisting of a Faraday cup connected to an electrometer. The diversity in physicochemical properties has shown a significant impact on the tribo-electric charging and adhesion behaviour of MC and HPMC.Moreover, the adhesion and electrostatic charge of the API was significantly reduced when MC and HPMC were incorporated and tribo-electric charging showed a linear relationship (R 2 = 0.81-0.98) with particle surface adhesion, however, other factors were also involved. It is anticipated that such a reduction in charge and particle surface adhesion would improve flow and compaction properties during processing.

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confidence: 99%

Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen

Ghori

Šupuk

Conway

2014

European Journal of Pharmaceutical Sciences

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“…The mechanism of molecular diffusion can be explained by the low presence of water in the powder, which interacts with the polar surface of the encapsulating agents, then during storage, compounds of essential oil could be replaced by water. In microspheres/microcapsules, the values of n indicate the following release mechanisms: for n ≤ 0.43, the dominant release mechanism is the Fickian diffusion (case I transport); 0.43 ≤ n < 0.85 indicates the diffusion and the swelling release mechanism (non-Fickian or anomalous transport); and n ≥ 0.85 corresponds to zero order release kinetics (case II transport) (Maderuelo et al, 2011;Siepmann and Peppas, 2001). Figure 3 shows the effect of the freezing method in the release of α− and β−citral (addition of both retentions) during storage in two different matrices.…”

Section: Release Kinetic Of Compounds During Storagementioning

confidence: 99%

LEMONGRASS (Cymbopogon citratus (DC) Stapf) ESSENTIAL OIL ENCAPSULATION BY FREEZE-DRYING

Enciso¹

2018

Rev. Mex. Ing. Quim.

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The objective of this study was to determine the effect of different encapsulating agents (gum arabic (GA), maltodextrin (MD) and/or xanthan gum (XG) and two different freezing methods (slow and fast)) on the encapsulating efficiency of Cymbopogon citratus essential oil and on its release during storage. Retention of α− and β−citral, β−myrcene and linalool were determined by Gas Chromatography Mass Spectra (GC MS). Release of the encapsulated compounds was determined at 76% relative humidity and 30°C. The highest retention obtained was 78±9% for β−citral, 100±16% for α−citral, 81.6±5.8% for β−myrcene and 39.7±2.3% for linalool with the slow tested freezing protocol and a mixture of 50% GA, 40% MD, and 10% XG (volume). Kinetic release during storage was exponential and adequately fitted with Avrami´s model. Lemongrass essential oil can be encapsulated by freeze-drying using a mixture of gum arabic, maltodextrin and xanthan gum with a high retention of volatile compounds by using a slow freezing protocol. Keywords: Cymbopogon citratus, citral, myrcene, linalool, freeze-drying. ResumenEl objetivo de este trabajo fue determinar el efecto de diferentes mezclas de agentes encapsulantes (goma arábiga (GA), maltodextrina (MD) y/o goma xantana (GX) y dos diferentes métodos de congelamiento (lento y rápido)) sobre la eficiencia de encapsulamiento del aceite esencial de Cymbopogon citratus y evaluar su liberación durante el almacenamiento. La retención de α− y β−citral, β−mirceno y linalol se determinaron mediante cromatografía de gases con espectrometría de masas (CG EM). La liberación de los compuestos durante el almacenamiento se evaluó a 76% de humedad relativa y 30°C. Las retenciones más altas obtenidas fueron 78±9% para β−citral, 94±5.6% para α−citral, 81.6±5.8% para β−mirceno y 39.7±2.3% para linalol, utilizando congelación lenta y una mezcla de 50% GA, 40% MD y 10% GX (volumen). La cinética de liberación de compuestos durante el almacenamiento fue exponencial y ajustada con el modelo de Avrami. El aceite esencial de zacate limón puede ser encapsulado mediante liofilización usando una mezcla de goma arábiga, maltodextrina y goma xantana con una retención elevada de compuestos volátiles utilizando una congelación lenta.

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“…39 The more the concentration of HPMC, thicker the gel layer offers more resistance to the drug diffusion and gel erosion, 40 which results in the incomplete release. SA matrix had the ability to provide a sustained release for highly water-soluble drug even in the presence of water-soluble excipients like HPMC 41 the pH independent release profile for basic drugs like MS can be attained by combining HPMC with SA.…”

Section: In Vitro Dissolution Studiesmentioning

confidence: 99%

Effect of Sodium alginate in Combination With HPMC K 100 M in Extending the Release of Metoprolol Succinate from its Gastro-Retentive Floating Tablets

Thulluru¹,

Varma²,

Setty³

et al. 2015

IJPER

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Aim of work:The aim of present study was to convert Metoprolol Succinate (MS) into Gastro Retentive Floating Tablet (GRFT) and simultaneously to determine the effect of Sodium alginate (SA) in combination with HPMC K 100M in extending the release of MS. Method: The drug-excipients compatibility studies of MS and the polymers were carried by FTIR studies. The effervescent GRFT of MS was prepared by non aqueous wet granulation. All Formulations were evaluated for pre-compression, postcompression, in vitro buoyancy and accelerated stability studies: for the best formulation for 3 months. Results: The drug-excipients compatibility studies reveals that MS and the polymers used are compatible. Evaluation parameters were within the acceptable limits for all formulations. in vitro dissolution studies, showed the formulation F4 having the combination of 20% HPMC K100M and 10% SA is exhibiting better extended release up to 12 h, with a Floating Lag Time (FLT) of 20 s, Total Floating Time (TFT) and Matrix Integrity (MI) maintained up to 12 h than other formulations. Regression Coefficients of Zero order and Higuchi equations suggested the drug release follows Zero order and is predominantly by diffusion respectively. The Diffusion exponent (n) of KorsmeyerPeppas model suggested the release mechanism is by non-Fickian transport. DSC studies further confirmed the drug is in the same state even in the optimized formulation F4 with out interacting with the polymers and excipients in the formulation. Accelerated stability studies indicate no significant differences in the optimized formulation F4. Conclusion: In conclusion, by optimizing the right ratios of the release-retarding gel-forming polymers HPMC K100M and SA, GRFT of MS with a better extended release up to 12 h was formulated.

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Critical factors in the release of drugs from sustained release hydrophilic matrices

Cited by 436 publications

References 167 publications

Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen

Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen

LEMONGRASS (Cymbopogon citratus (DC) Stapf) ESSENTIAL OIL ENCAPSULATION BY FREEZE-DRYING

Effect of Sodium alginate in Combination With HPMC K 100 M in Extending the Release of Metoprolol Succinate from its Gastro-Retentive Floating Tablets

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