Characterisation of water behaviour in cellulose ether polymers using low frequency dielectric spectroscopy

McCrystal, Conor B.; Ford, James L.; He, Renren; Craig, Duncan Q.M.; Rajabi‐Siahboomi, Ali R.

doi:10.1016/s0378-5173(02)00275-2

Cited by 11 publications

(7 citation statements)

References 12 publications

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“…It has been hypothesized that there is more than one state of water in the matrix gel. The water may be regarded as (a) tightly bound water that interacts with polymer chains and is non freezable, (b) free water that is freezable and (c) water in states between these two extremes (Ford & Mitchell 1995;McCrystal et al 1997McCrystal et al , 2002Nokhodchi et al 1997). Nokhodchi et al (1997) predicted that hypromellose 2208 containing as much as $31% w/w moisture would show no free water as all the moisture is tightly bound.…”

Section: Hydration Statementioning

confidence: 99%

The use of hypromellose in oral drug delivery

Martini

Ford

et al. 2005

Journal of Pharmacy and Pharmacology

288

149

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Hypromellose, formerly known as hydroxypropylmethylcellulose (HPMC), is by far the most commonly employed cellulose ether used in the fabrication of hydrophilic matrices. Hypromellose provides the release of a drug in a controlled manner, effectively increasing the duration of release of a drug to prolong its therapeutic effect. This review provides a current insight into hypromellose and its applicability to hydrophilic matrices in order to highlight the basic parameters that affect its performance. Topics covered include the chemical, thermal and mechanical properties of hypromellose, hydration of the polymer matrices, the mechanism of drug release and the influence of tablet geometry on drug-release rate. The inclusion of drug-release modifiers within hypromellose matrices, the effects of dissolution media and the influence of both the external environment and microenvironment pH within the gel matrix on the properties of the polymer are also discussed.

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Section: Hydration Statementioning

confidence: 99%

The use of hypromellose in oral drug delivery

Martini

Ford

et al. 2005

Journal of Pharmacy and Pharmacology

288

149

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“…Various methods have been used in the study of the different types of water in hydrated polymers. These methods include low frequency dielectric spectroscopy, 11 differential scanning calorimetry, 1,2,4,6-8 differential thermal analysis, 12 thermogravimetric analysis, 3,12 immersion calo-In the pharmaceutical field, ethylcellulose is a polymer used to prepare sustained-release medications of various types. Although ethylcellulose is considered insoluble, it can take up water.…”

mentioning

confidence: 99%

Studies on the interaction of water with ethylcellulose: Effect of polymer particle size

et al. 2003

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The purpose of this research was to investigate the interaction of water with ethylcellulose samples and assess the effect of particle size on the interaction. The distribution of water within coarse particle ethylcellulose (CPEC; average particle size 310 micro m) and fine particle ethylcellulose (FPEC; average particle size 9.7 micro m) of 7 cps viscosity grade was assessed by differential scanning calorimetry (DSC) and dynamic vapor sorption analysis. The amounts of nonfreezing and freezing water in hydrated samples were determined from melting endotherms obtained by DSC. An increase in water content resulted in an increase in the enthalpy of fusion of water for the two particle size fractions of EC. The amount of nonfreezable water was not affected by the change in particle size at low water contents. Exposure of ethylcellulose to water for 30 minutes is sufficient to achieve equilibration within the hydrated polymer at 47% wt/wt water content. The moisture sorption profiles were analyzed according to the Guggenheim-Anderson-de Boer (GAB) and Young and Nelson equations, which can help to distinguish moisture distribution in different physical forms. The amount of externally adsorbed moisture was greater in the case of FPEC. Internally absorbed moisture was evident only with the CPEC. In light of these results, an explanation is offered for the success of FPEC in wet-granulation methods where CPEC was not successful.

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“…Nuclear magnetic resonance (NMR) and FT Raman spectroscopy Nuclear magnetic resonance spectra Mobility of water molecules in a system Khan and Pilpel 1987;Martinez et al 1990;Suryanarayanan and Wiedmann 1990;Yoshioka et al 1992Yoshioka et al , 1995Aso et al 1994Aso et al , 1997Taylor et al 2001;McCrystal et al 2002;Suzuki and Kawasaki 2005 Strength of the hydrogen bonds with water Determination of plasticizing effect of water on polymer mobility, differentiation between samples in rubbery and glassy state Pikal et al 1977;Hollenbeck et al 1978;Angberg et al 1988Angberg et al , 1990Angberg et al , 1991Angberg et al , 1992aAngberg et al , 1992bFielden et al 1988;Buckton andBeezer, 1988, 1991;Pikal and Dellerman 1989;Blair et al 1990;Angberg 1995;Pudipeddi et al 1996;Buckton 2000 …”

Section: Analytical Techniques Used To Characterize Water In Solidsmentioning

confidence: 99%

“…Subtracting the amount of FBW and FW from the total water content of a sample the amount of non-freezing water could be estimated using DSC measurements (Hodge et al 1996). The mobility of water molecules in a system can be directly measured by nuclear magnetic resonance (NMR) and dielectric relaxation spectroscopy (DRS) (Khan and Pilpel 1987;McCrystal et al 2002;Yoshioka et al 1992Yoshioka et al , 1995Otsuka et al 1995;Aso et al 1994Aso et al , 1997. Mobility of water in the system has been correlated with drug stability in API-excipient mixtures in a number of studies; e.g.…”

Section: Analytical Techniques Used To Characterize Water In Solidsmentioning

confidence: 99%

Excipient Selection in Oral Solid Dosage Formulations Containing Moisture Sensitive Drugs

Rajabi‐Siahboomi

Levina²,

Upadhye

et al. 2015

Excipient Applications in Formulation Design and Drug Delivery

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Moisture sensitivity of active pharmaceutical ingredients (APIs) presents a formidable challenge in the formulation of oral dosage forms. The interaction of moisture with APIs is crucial to an understanding of water-based processes, e.g. manufacturing or prediction of solid dosage form stability and shelf-life. Unwarranted moisture sorption by either APIs or excipients can result in unstable oral solid formulations. The appropriate selection of excipients for the core formulation and appropriate moisture barrier film coating helps to remedy the moisture-related issues with APIs and thus can improve the storage stability of the final formulations. In this chapter, we review the nature and extent of the moisture sensitivity and possible approaches taken to overcome it. Use of excipients that bind tightly with water reduce its potential interaction with the API. In addition, application of a barrier coating to reduce rate and extent of moisture ingress into the core of the solid dosage form during the storage (in original packaging or while in-use), are some of the many simple options that have been considered and described.Keywords Calorimetry · Degradation · Differential scanning calorimetry · Dynamic vapor sorption · Equilibrium relative humidity · Excipients · Isothermal microcalorimetry · Moisture · Moisture-barrier coating · Near-infra red Spectroscopy · Opadry · Optical waveguide spectroscopy · Packaging · Stability · Water · Water vapor transmission rate Abbreviations AluAluminum API Active pharmaceutical ingredient

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Characterisation of water behaviour in cellulose ether polymers using low frequency dielectric spectroscopy

Cited by 11 publications

References 12 publications

The use of hypromellose in oral drug delivery

The use of hypromellose in oral drug delivery

Studies on the interaction of water with ethylcellulose: Effect of polymer particle size

Excipient Selection in Oral Solid Dosage Formulations Containing Moisture Sensitive Drugs

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