Calorimetric study of aqueous solutions of hydroxypropyl cellulose

Robitaille, Lucie; Turcotte, Nancy; Fortin, Suzie; Charlet, Gérard

doi:10.1021/ma00009a044

Cited by 38 publications

(28 citation statements)

References 5 publications

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“…Consequently, HPC shows different solubilities in different solvents. Complex phase diagrams, including the LC phases and the cloudy suspension phases (CS), have been obtained for HPC solutions in various solvents at various temperatures (Fortin and Charlet 1989;Robitaille et al 1991;Guido 1995;Lárez-V et al 1995).…”

Section: Introductionmentioning

confidence: 99%

3-D phase diagram of HPC/H2O/H3PO4 tertiary system

Rwei

Lyu

2012

Cellulose

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A 3-D phase diagram of the HPC/H 2 O/ H 3 PO 4 tertiary system against various temperatures was established. Four distinct phases-the completely separated phase (S), the cloudy suspension phase (CS), the liquid crystalline miscible phase (LC), and the isotropically miscible phase (I)-were identified. The S phase shrank as the temperature increased, revealing that the HPC solubility increased with temperature, regardless of the LCST (lower critical solution temperature) characteristic. The addition of H 3 PO 4 suppressed the formation of LC phase. However, as the temperature was raised sharply from 50 to 70°C, the LC phase could only be maintained at high H 3 PO 4 concentration region; it was a triangular shape, and the top apex of the triangle was the temperature-invariant L* point (HPC/H 2 O/H 3 PO 4 38/9/53 wt%). The CS phase expanded considerably into the H 2 O-rich but H 3 PO 4 -poor region when the temperature continued to increase over 48°C. The LCST points of the CS phase that contained 0 and 15 wt% of H 3 PO 4 were 34 and 38°C, respectively. These CS results demonstrate that H 3 PO 4 suppresses the occurrence of LCST behavior. Additionally, the binodal curve exhibits a weak or even zero dependence of binodal temperature on the HPC concentration at HPC concentrations of less than 30 wt% in a pure water system. A hypothesis concerning the sequential desorption of water molecules was proposed to explain such behavior.

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Section: Introductionmentioning

confidence: 99%

3-D phase diagram of HPC/H2O/H3PO4 tertiary system

Rwei

Lyu

2012

Cellulose

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“…The spectra were recorded in DMSO-d6 at 95°C to improve the resolution. 30 In the spectrum of HPC (Fig. 3), a peak at a chemical shift of 4.4 ppm was observed.…”

Section: Evidence Of Graft Copolymer Formation From Nmr Spectroscopymentioning

confidence: 94%

“…The peak at 1.06 ppm was assigned to the methyl protons in the hydroxypropyl groups (H x ). 30,31 The 1 H-NMR spectrum of component M n ϭ number-average molecular weight. a The sum of the feed amounts of HPC and CL.…”

Section: Evidence Of Graft Copolymer Formation From Nmr Spectroscopymentioning

confidence: 99%

“…30,31 The method is based on the fact that each different proton in different structural groups gives rise to peaks at a characteristic magnetic field strength, and the peak intensity is directly proportional to the concentration of the protons. Peak intensity in an 1 H-NMR spectrum is affected by experimental parameters such as pulse angle and relaxation delay.…”

Section: Molar Substitution (Ms)mentioning

confidence: 99%

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Synthesis and characterization of amphiphilic hydroxypropylcellulose‐graft‐poly(ε‐caprolactone)

Shi

Burt

2003

J of Applied Polymer Sci

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An amphiphilic graft copolymer, hydroxypropylcellulose-graft-poly(-caprolactone) (HPC-g-PCL), was synthesized by bulk polymerization without a catalyst and characterized with one-dimensional and two-dimensional NMR spectroscopy. Molar substitution of -caprolactone on HPC (MS CL ) was estimated by both gravimetry and 1 H-NMR, and the gravimetric method was considered suitable for MS CL determination. Heterogeneity in the HPC-g-PCL film was suggested by a microscopic study, and the existence of PCL-rich crystalline regions was confirmed by the results of X-ray diffraction and differential scanning calorimetry (DSC). The double endotherm observed in the DSC scans of HPC-g-PCL was associated with the different molecular weight fractions in the copolymer.

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“…In contrast to MC and HPMC, only a few studies have investigated the gelation mechanism of HPC by NMR spectroscopy and thermal analysis [75,76].…”

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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Calorimetric study of aqueous solutions of hydroxypropyl cellulose

Cited by 38 publications

References 5 publications

3-D phase diagram of HPC/H2O/H3PO4 tertiary system

3-D phase diagram of HPC/H2O/H3PO4 tertiary system

Synthesis and characterization of amphiphilic hydroxypropylcellulose‐graft‐poly(ε‐caprolactone)

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

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