A new one‐point intrinsic viscosity method

Rudin, Alfred; Wagner, Richard

doi:10.1002/app.1975.070191220

Cited by 26 publications

(10 citation statements)

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“…Intrinsic viscosities of the polymers were determined by measuring the viscosity of the plasticizer (where liquid) and a solution of known concentration of the polymer (usually between 0.1 and 0.5% w/w) using a 'U' tube viscometer and substituting these values in the equations of Rudin & Wagner (1975). All measurements were made at 25 "C.…”

Section: A T E R I a L S A N D M E T H O D Smentioning

confidence: 99%

“…t While it is realised that ethylene glycol, diethylene glycol, triethylene glycol and dipropylene glycol would not normally be used in the film coating of solid dosage forms because of their toxicity, they have been included In this study in order to examine the effect of plasticizer molecular weight.Intrinsic viscosities of the polymers were determined by measuring the viscosity of the plasticizer (where liquid) and a solution of known concentration of the polymer (usually between 0.1 and 0.5% w/w) using a 'U' tube viscometer and substituting these values in the equations of Rudin & Wagner (1975). A correlation was found between the intrinsic viscosity of the polymer/plasticizer solutions and the tensile strength, elongation at rupture and work done in stressing to failure of cast films-the mechanical properties being at a minimum when the intrinsic viscosity was at a maximum.…”

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confidence: 99%

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Plasticization of cellulose ethers used in the film coating of tablets

Entwistle¹,

Rowe²

1979

Journal of Pharmacy and Pharmacology

102

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plasticizer/polymer interactions have been studied by measuring the intrinsic viscosities of both ethyl cellulose and hydroxypropyl methylcellulose in a series of dialkyl phthalates and in a series of liquid glycols respectively. A correlation was found between the intrinsic viscosity of the polymer/plasticizer solutions and the tensile strength, elongation at rupture and work done in stressing to failure of cast films-the mechanical properties being at a minimum when the intrinsic viscosity was at a maximum. This correlation held only within a homologous series of plasticizers and none was found for plasticizers of different structures. A relationship was found between the lowering of a calculated glass transition temperature of hydroxypropyl methylcellulose in the presence of the plasticizers propylene glycol, polyethylene glycol 200 and glycerol and the intrinsic viscosity of the corresponding solutions-the higher the viscosity the greater the lowering of the transition temperature.Film formers such as the cellulpse ethers, ethyl cellulose and hydroxypropyl methylcellulose are now used extensively in the film coating of solid dosage forms. Plasticizers are often added to these polymers in order to change their physical properties and enhance their film forming characteristics. To be effective a plasticizer must interpose itself between the polymer chains and interact with the forces holding the chains together thereby extending and softening the polymer matrix. A very convenient way of assessing the degree of plasticizer/poiymer interaction is to measure the intrinsic viscosity of the polymer dissolved in the plasticizer. In this work these measurements have been made for ethyl cellulose and hydroxypropyl methyl cellulose in a series of liquid plasticizers and correlated with both glass transition temperatures and the mechanical properties of free films. M A T E R I A L S A N D M E T H O D SThe two polymers used were ethyl cellulose (Grade N50, Hercules Powder Co. Ltd., U.S.A.) and hydroxypropyl methylcellulose U.S.P. (Pharmacoat 606, Shinetsu Chemical Co. Ltd., Japan). Dimethyl phthalate, diethyl phthalate, dibutyl phthalate and dioctyl phthalate were used as plasticizers for the ethyl cellulose; ethylene glycol, diethylene glycol, triethylene glycol, the polyethylene glycols 200, 300, 400, 600, 1O00, 4OO0, 6000, propylene glycol, dipropylene glycol and glycerol were used as plasticizers for the hydroxypropyl methylcellulose.~ * Correspondence. t While it is realised that ethylene glycol, diethylene glycol, triethylene glycol and dipropylene glycol would not normally be used in the film coating of solid dosage forms because of their toxicity, they have been included In this study in order to examine the effect of plasticizer molecular weight.Intrinsic viscosities of the polymers were determined by measuring the viscosity of the plasticizer (where liquid) and a solution of known concentration of the polymer (usually between 0.1 and 0.5% w/w) using a 'U' tube viscometer and substituting these values in the equa...

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Section: A T E R I a L S A N D M E T H O D Smentioning

confidence: 99%

mentioning

confidence: 99%

Plasticization of cellulose ethers used in the film coating of tablets

Entwistle¹,

Rowe²

1979

Journal of Pharmacy and Pharmacology

102

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“…Since the GPC elution volume is a function of [~] i M i ,~ the GPC chromatogram yields Ji and corresponding values of wi (after normalization), provided all species elute effectively at infinite dilution.3 With suitable substitution^,^ and = K-l/(a+l) C wi J l / ( a + l ) (5) (7) [v]f/[v] = C wi' Jifd(a+l)/C wiJp/(a+l) (8) In eq. (8) the primed and unprimed terms refer to different samples of the same polymeric type.…”

Section: Theorymentioning

confidence: 99%

“…In principle, any one of eqs. (6), (7), or (8) can be used with the appropriate data to obtain an independent measure of a, and eq. Gel permeation chromatography involved tetrahydrofuran (THF) solutions with 2 mg/ml concentrations.…”

Section: Theorymentioning

confidence: 99%

Evaluation of GPC methods for estimation of Mark–Houwink–Sakurada constants

Dobbin

Rudin

Tchir

1980

J. Appl. Polym. Sci.

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SynopsisConstants for the Mark-Houwink-Sakurada relation can be established in principle from GPC measurements on broad distribution polymers. The method requires use of two samples with dif- on the GPC measurement of Vn. The simplest and safest way to use GPC data to estimate the MHS constants involves the measurement of GPC chromatograms of two polymer samples with different intrinsic viscosities. The method is not confined to the solvent used as the GPC eluant. The MHS constants derived from GPC appear to reflect the molecular weight range of the calibration samples and may not be as widely applicable as those from the more tedious classical methods which employ a series of fractionated samples.

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“…(5), (7), and Mi = (Ji/K)'/("+') (10) K 2 = ([q]2K"d("+1))/(x ~~J~n 2 / ( " + 1 ) ) (11) it then follows that Thus, once K and a for the GPC solvent are obtained, the ratio of intrinsic viscosities of two polymers in a second solvent can be used to calculate the MHS constants for the latter solutions from eqs. (8) and (11).…”

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Use of broad distribution polymers and GPC methods for estimation of Mark–Houwink–Sakurada constants

Dobbin

Rudin

Tchir

1982

J of Applied Polymer Sci

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A recent article from this laboratory' contained an error in analysis which we are correcting herein. The cited paper considered the use of gel permeation chromatography (GPC) to determine the Mark-Houwink-Sakurada (MHS) constants for polymers in various solvents. The procedure outlined earlier for the GPC solvent'V2 requires no correction, but the reported extension of this method to solvents other than that used in the GPC analysis is more properly applied as follows. and GPC analyses are all obtained in the same solvent. In eq. (2) the exponent a is the MHS exponent in the familiar expression

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A new one‐point intrinsic viscosity method

Cited by 26 publications

References 28 publications

Plasticization of cellulose ethers used in the film coating of tablets

Plasticization of cellulose ethers used in the film coating of tablets

Evaluation of GPC methods for estimation of Mark–Houwink–Sakurada constants

Use of broad distribution polymers and GPC methods for estimation of Mark–Houwink–Sakurada constants

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