Effect of particle size and sorbed moisture on the compression behaviour of some hydroxypropyl methylcellulose (HPMC) polymers

Malamataris, S.; Karidas, Th.; Goidas, P.

doi:10.1016/0378-5173(94)90170-8

Cited by 44 publications

(14 citation statements)

References 10 publications

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“…Other studies have shown that the methoxy/hydropropoxy substitution ratio has a significant effect on the externally adsorbed moisture and the tightly bound monomolecular water. 41,42 …”

Section: Resultsmentioning

confidence: 98%

Studies on the Interaction Between Water and (Hydroxypropyl)Methylcellulose

Nokhodchi

Ford

Rubinstein

1997

Journal of Pharmaceutical Sciences

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The moisture sorption and desorption profiles of four different viscosity grades of (hydroxypropyl)methylcellulose (HPMC) 2208 (HPMC K100, HPMC K4M, HPMC K15M, and HPMC K100M) of different particle size fractions were analyzed according to the Young and Nelson equations. These equations describe three locations of the sorbed moisture: monolayer adsorption, externally adsorbed moisture, and internally absorbed moisture. The effects of particle size and viscosity grade of HPMC on the three locations of moisture showed that an increase in particle size generally resulted in a reduction in the amount of internal absorption and an increase in the amount of external adsorption. These changes were more apparent for HPMC K100 and HPMC K4M than for the higher viscosity grades. The lowest values of internally absorbed moisture were obtained for HPMC K100M. Changes in tensile strengths, mean yield pressures, and elastic recoveries of HPMC K4M tablets were explained in terms of the changes produced in the internally absorbed moisture and the externally adsorbed moisture. The amounts of nonfreezing and freezing water in samples exposed to moisture were determined from melting endotherms obtained by differential scanning calorimetry. Increases in the water:HPMC ratio resulted in increases in the enthalpies of water melting for the four viscosity grades of HPMC for the < 45 and 250-350 microns particle size fractions. The amount of nonfreezable water was unaffected by change in viscosity grade or particle size.

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“…Other studies have shown that the methoxy/hydropropoxy substitution ratio has a significant effect on the externally adsorbed moisture and the tightly bound monomolecular water. 41,42 …”

Section: Resultsmentioning

confidence: 98%

Studies on the Interaction Between Water and (Hydroxypropyl)Methylcellulose

Nokhodchi

Ford

Rubinstein

1997

Journal of Pharmaceutical Sciences

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“…These equations quantitatively describe moisture distribution in the sample, and have not been replaced by a better alternative. For that reason these equations have been extensively used in the literature 15–17,41–44…”

Section: Resultsmentioning

confidence: 99%

Water Distribution Studies Within Microcrystalline Cellulose and Chitosan using Differential Scanning Calorimetry and Dynamic Vapor Sorption Analysis

Agrawal

Manek

Kolling

et al. 2004

Journal of Pharmaceutical Sciences

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“…1 Different polymer properties have been reported to be responsible for the rate of polymer hydration including polymer viscosity grade, 2-4 polymer particle size, [5][6][7][8] polymer concentration, 2 and polymer substitution type. 5 It was initially proposed by Alderman 5 that cellulose ethers of different substitution levels hydrate at different rates, and this factor may be used to optimize the formulation of sustained release matrices.…”

Section: Introductionmentioning

confidence: 99%

Water distribution studies within cellulose ethers using differential scanning calorimetry. 2. Effect of polymer substitution type and drug addition

McCrystal

Ford

Rajabi‐Siahboomi

1999

Journal of Pharmaceutical Sciences

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The distribution of water within gels composed of a range of cellulose ether polymers of similar molecular weights (viscosity grades of 4000-6000 cP) but varying substitution types and levels was assessed by differential scanning calorimetry (DSC). Water loosely bound to the polymer was detected as one or more events appearing at the low-temperature side of the main endotherm for the melting of free water in DSC scans. Polymer substitution types and levels, and added drugs (50 mM propranolol hydrochloride or 50 mM diclofenac sodium) influenced the appearance of these melting events. Hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose (HPMC F4M) gels showed behavior different to that of the other polymers studied. It is thought that any water binding to HPC gels is tightly attached and is not visible as pre-endothermic events on DSC scans. The amount of water bound per polymer repeating unit (PRU) was influenced by and related to the degree of hydrophilic and hydrophobic substitution on the polymer backbone and by the inclusion of either drug. HPC gels had the highest bound water content after 96 h and this was probably related to the high percentage of hydrophilic hydroxypropoxyl substitutions in this polymer. In contrast, methylcellulose (MC A4M) had the lowest bound water content after 96 h storage, and this was explained by the lack of hydrophilic hydroxypropoxyl substitutions in the polymer.

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Effect of particle size and sorbed moisture on the compression behaviour of some hydroxypropyl methylcellulose (HPMC) polymers

Cited by 44 publications

References 10 publications

Studies on the Interaction Between Water and (Hydroxypropyl)Methylcellulose

Studies on the Interaction Between Water and (Hydroxypropyl)Methylcellulose

Water Distribution Studies Within Microcrystalline Cellulose and Chitosan using Differential Scanning Calorimetry and Dynamic Vapor Sorption Analysis

Water distribution studies within cellulose ethers using differential scanning calorimetry. 2. Effect of polymer substitution type and drug addition

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