Interplay between Gelation and Phase Separation in Aqueous Solutions of Methylcellulose and Hydroxypropylmethylcellulose

Fairclough, J. Patrick A.; Yu, Hao; Kelly, O.; Ryan, Anthony J.; Sammler, Robert L.; Radler, Michael J.

doi:10.1021/la300971r

Cited by 79 publications

(126 citation statements)

References 48 publications

(57 reference statements)

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“…It has attracted much research attention because it resonates with the concept of green chemistry and sustainable material world (Lott et al 2013b). Similar to the sol-gel transition behavior of other cellulose ethers such as methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) in water (Bajwa et al 2009;Fairclough et al 2012;Haque and Morris 1993;Kobayashi et al 1999), aq. HPC solutions show thermoreversible phase transition behavior, i.e.…”

Section: Introductionmentioning

confidence: 78%

Thermal inverse phase transition of azobenzene hydroxypropylcellulose in aqueous solutions

Zhang

Liu

2016

Cellulose

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Water soluble 2-azobenzenoxy-ethoxyhydroxpropylcelluloses (azo-EHPC) were synthesized by etherification reaction of bromoethoxy-azobenzene (BEA) with hydroxypropylcellulose (HPC) to study their phase transition behavior in aq. solution. The degree of substitution (DS) of the water soluble azoEHPCs was less than 0.066. Their chemical structure and thermal property were characterized by proton nuclear magnetic resonance ( 1 H-NMR), fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry. The azo-EHPC showed a reversible sol-gel transition behavior in its aq. solution, i.e. a clear azo-EHPC aq. solution became turbid when the solution temperature surpassed a lower critical solution temperature (LCST). The sol-gel transition phenomenon was investigated by optical microscopy and turbidimetric measurement. It was found that the LCST was related to the cis-/transconformation of the azobenzene side group, the type of cyclodextrin (CD), concentration of azo-EHPC, and NaCl concentration. The LCST of azo-EHPC was lower than that of HPC (36.6°C) by at most 13.6°C, and the LCST of trans-azo-EHPC was less than that of cis-azo-EHPC by ca. 3°C. Additionally, the presence of CD in solutions displayed a positive effect on the LCST, i.e. increasing the LCST by 3-5°C. And this impact was more profound on the azo-EHPC with higher DS values. The thermoreversible phase transition mechanism was discussed. We proposed that the effect of DS, conformation of azobenzene group, azo-EHPC concentration, salt concentration, and CD on the LCST of azo-EHPCs was a rearrangement of the hydrophilic/hydrophobic interaction between side azobenzene groups and water molecules.

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Section: Introductionmentioning

confidence: 78%

Thermal inverse phase transition of azobenzene hydroxypropylcellulose in aqueous solutions

Zhang

Liu

2016

Cellulose

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“…These factors cause the gradual decrease of light transmittance upon heating. In fact, aqueous hydroxypropyl methylcellulose (HPMC), which has poorer gelation ability than aqueous MC [17,34], does not show such a gradual decrease in the light transmittance curve but shows only a sharp fall [6,11]. Therefore, the gradual decrease and the sharp fall in the light transmittance are assigned to the optical aspects of the gelation and the phase separation, respectively, at least for a specific MC used in the present study.…”

Section: Heating Rate Dependence Of Cloud Pointmentioning

confidence: 74%

“…The reduction of the hydrogen bonding is achieved by partially substituting hydrophobic methoxy group for hydrophilic hydroxy group in cellulose molecule. The temperature-sensitive behaviors of MC originate from the concert effects of these hydrophilic and hydrophobic interactions [5,6] . The transition temperatures, such as the gelation and phase separation temperatures, are affected by the degree of substitution and also by the distribution pattern of the substituents [5,[7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Quasi-Equilibrium Gelation Temperature of Aqueous Methylcellulose

Nishida

Saiga

Fujishima

et al. 2016

JFST

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“…Also, as the temperature rise to ca. 55°C, hydroxypropyl derivative of MC precipitates and causes only clouding of the solution, but no gelation, unlike MC [53,[72][73][74].…”

Section: Colloidal Dissolution and Gelation As Processes Involved In mentioning

confidence: 99%

Cellulose-Derivatives-Based Hydrogels as Vehicles for Dermal and Transdermal Drug Delivery

Vlaia¹,

Coneac²,

Olariu³

et al. 2016

Emerging Concepts in Analysis and Applications of Hydrogels

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The use of water-soluble polymers of natural, semisynthetic, and synthetic origin for dermal and transdermal drug delivery systems is manifold. Among the most used biopolymers in the formulation of skin preparations, the cellulose ether derivatives as representatives of semisynthetic polymers distinguish through their specific physicochemical properties, by which the pharmacist can select the appropriate cellulose derivative for a particular purpose. The hydrogels containing cellulose derivatives as gelling agents are widely used as water-soluble ointment bases, because they usually associate the characteristics of both conventional and innovative hydrogels, including especially safety, biocompatibility, biodegradability, and a relatively easy way of preparation and low price. The present chapter describes the following issues: the physicochemical properties of water-soluble cellulose derivatives in relationship with their type and grade; physical and chemical properties of cellulose-derivatives-based hydrogels and their compatibility with other auxiliary substances commonly used in the formulation of pharmaceutical hydrogels; the development and manufacturing of these hydrogels on both small and large scales; the characterization of cellulose derivatives hydrogels as pharmaceutical dosage forms through different compendial and noncompendial methods; and well-recognized and novel applications of cellulosederivatives-based hydrogels for dermal and transdermal drug delivery.

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Interplay between Gelation and Phase Separation in Aqueous Solutions of Methylcellulose and Hydroxypropylmethylcellulose

Cited by 79 publications

References 48 publications

Thermal inverse phase transition of azobenzene hydroxypropylcellulose in aqueous solutions

Thermal inverse phase transition of azobenzene hydroxypropylcellulose in aqueous solutions

Quasi-Equilibrium Gelation Temperature of Aqueous Methylcellulose

Cellulose-Derivatives-Based Hydrogels as Vehicles for Dermal and Transdermal Drug Delivery

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