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AAPS PharmSciTech. 2002 February; 3(4): 86.
Published online 2002 December 28. doi:  10.1208/pt030436
PMCID: PMC2751345

Investigation of the state and dynamics of water in hydrogels of cellulose ethers by1H NMR spectroscopy


The aim of this work was to study the effect of the type of substituent of the cellulose ethers and the molecular mass on the state and dynamics of water in the respective hydrogels to specify the quantity of adsorbed water on the polymers or, more explicitly, to calculate the average number of water molecules bound to a polymer repeating unit (PRU).1H NMR relaxation experiments were performed on equilibrated systems of cellulose ether polymers (HEC, HPC, HPMC K4M, and HPMC K100M) with water. In particular, the water proton spinlattice (T1) and spin-spin (T2) relaxation times were measured in these systems at room temperature. The observed proton NMRT1 andT2 of water in hydrogels at different cellulose ether concentrations at room temperature were shown to decrease with increasing polymer concentration. The relaxation rate 1/T1 is sensitive to the type of polymer substituent but insensitive to the polymer molecular mass. The rate 1/T2 appears much less influenced by the polymer substitution. The procedure developed for calculating the amount of water bound per PRU, based on the analysis of theT1 andT2 data, shows that this amount is the largest for HPC followed by HEC, HP MC K4M, and HPMC K100M. The results correlate well with the degree of hydrophilic substitution of the polymer chains. This NMR analysis deals with a single molecular layer of adsorbed water for the investigated cellulose ether polymers at all concentrations, while the rest of the water in the hydrogel is bulk-like. Therefore, the mesh size of polymer network in the view of a single molecular layer is not effectively changed.

Keywords: Cellulose ethers, hydrogel, controlled release, Nuclear Magnetic Resonance, proton NMR relaxation

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
1. Siepmann J, Kranz H, Bodmeier R, Peppas NA. HPMC-Matrices for controlled drug delivery: a new model combining diffusion, swelling, and dissolution mechanisms and predicting the release kinetics. Pharm Res. 1999;16:1748–1756. doi: 10.1023/A:1018914301328. [PubMed] [Cross Ref]
2. Colombo P, Bettini R, Peppas NA. Observation of swelling process and diffusion front position during swelling in hydroxypropyl methylcellulose (HPMC) matrices containing a soluble drug. J Control Release. 1999;61:83–91. doi: 10.1016/S0168-3659(99)00104-2. [PubMed] [Cross Ref]
3. Lowman AM, Peppas NA. Hydrogels. In: Mathiowitz E, editor. Encyclopedia of Controlled Drug Delivery. New York, NY: Wiley; 2000. pp. 397–417.
4. Néel TL, Morlet-Renaud C, Lipart C, Gouyette A, Truchaud A, Merle C. Image analysis as a new technique for the study of water uptake in tablets. STP Pharma Sciences. 1997;7:117–122.
5. Baumgartner S, Šmid-Korbar J, Vrečer F, Kristl J. Physical and technological parameters influencing floating properties of matrix tablets based on cellulose ethers. STP Pharma Sciences. 1998;8:182–187.
6. Rodriguez CF, Bruneau N, Barra J, Alfonso D, Doelker E. Hydrophilic cellulose derivatives as drug delivery carriers: influence of substitution type on the properties of compressed matrix tablets. In: Wise DL, editor. Handbook of Pharmaceutical Controlled Release Technology. New York, NY: Marcel Dekker; 2000. pp. 1–30.
7. Doekler E, Langer RS. Cellulose Derivatives. In: Peppas NA, editor. Advances in Polymer Science 107; Biopolymers I. Berlin, Germany: Springer-Verlag; 1993. pp. 200–262.
8. McCrystal CB, Ford JL, Rajabi-Siahboomi R. A study on the interaction of water and cellulose ethers using differential scanning calorimetry. Thermochim Acta. 1997;294:91–98. doi: 10.1016/S0040-6031(96)03148-6. [Cross Ref]
9. Baumgartner S, Kristl J, Peppas NA. Network structure of cellulose ethers used in pharmaceutical applications during swelling and at equilibrium. Pharm Res. 2002;8:1084–1090. doi: 10.1023/A:1019891105250. [PubMed] [Cross Ref]
10. Hatekeyama H, Hatekeyama T. Interaction between water and hydrophilic polymers. Thermochim Acta. 1998;308:3–22. doi: 10.1016/S0040-6031(97)00325-0. [Cross Ref]
11. Fyfe CA, Blazek AI. Investigation of hydrogel formation from hydroxypropylmethylcellulose (HPMC) by NMR spectroscopy and NMR imaging techniques. Macromolecules. 1997;30:6230–6237. doi: 10.1021/ma970076o. [Cross Ref]
12. McBrierty VJ, Martin SJ, Karasz FE. Understanding hydrated polymers: the perspective of NMR. J Mol Liquids. 1999;80:179–205. doi: 10.1016/S0167-7322(99)00023-9. [Cross Ref]
13. Carenza M, Cojazzi G, Bracci B, et al. The state of water in thermoresponsive poly(acryloyl-L-proline methyl ester) hydrogels observed by DSC and 1H NMR relaxometry. Radiat Phys Chem. 1999;55:209–218. doi: 10.1016/S0969-806X(98)00328-4. [Cross Ref]
14. Rajabi-Siahboomi AR, Bowtell RW, Mansfield P, Davies MC, Melia CD. Structure and behaviour in hydrophilic matrix sustained release dosage forms: 4. Studies of water mobility and diffusion coefficients in the gel layer of HPMC tablets using NMR imaging. Pharm Res. 1996;13:376–380. doi: 10.1023/A:1016084224084. [PubMed] [Cross Ref]
15. Katzhendler I, Mäder K, Azoury R, Friedmann M. Investigating the structure and properties of hydrated hydroxypropyl methylcellulose and egg albumin matrices containing carbamazepine: EPR and NMR study. Pharm Res. 2000;17:1299–1308. doi: 10.1023/A:1026408006665. [PubMed] [Cross Ref]
16. Kristl J, Lahajnar G, Jezernik K, Smid-Korbar J. Water behaviour in poly(methylmethacrylate) hydrocolloids studied by NMR techniques and electron microscopy. STP Pharma Sciences. 1992;2:265–269.
17. Yasunaga H., Shirakawa Y, Urakawa H, Kajiwara K. Dynamic behaviour of water in hydrogel containing hydrophobic side chains as studied by pulse 1H NMR. J Mol Struct. 2002;602–603:399–404. doi: 10.1016/S0022-2860(01)00704-9. [Cross Ref]
18. Blinc A, Lahajnar G, Blinc R, Zidanšek A, Sepe A. Proton NMR study of the state of water in fibrin gels, plasma, and blood clots. Magn Reson Med. 1990;14:105–122. doi: 10.1002/mrm.1910140111. [PubMed] [Cross Ref]
19. Gadian DG. Nuclear magnetic resonance and its applications to living systems. Oxford, England: The Alden Press Ltd; 1984.
20. Smith MB, Shung KK, Mosher TJ. Magnetic Resonance Imaging. In: Shung KK, Smith MB, Tsui B, editors. Principles of Medical Imaging. San Diego, CA: Academic Press Inc; 1992. pp. 213–273.
21. Blinc R, Rutar V, Zupančič I, Zidanšek A, Lahajnar G, Slak J. Proton NMR relaxation of adsorbed water in gelatin and collagen. Appl Magn Reson. 1995;9:193–216. doi: 10.1007/BF03162042. [Cross Ref]
22. Rajabi-Siahboomi AR, Bowtell RW, Mansfield P, Henderson A, Davies MC, Melia CD. Structure and behaviour in hydrophilic matrix sustained release dosage forms: 2. NMR-imaging studies of dimensional changes in the gel layer and core of HPMC tablets undergoing hydration. J Control Release. 1994;31:121–128. doi: 10.1016/0168-3659(94)00016-6. [Cross Ref]
23. Baumgartner S, Tivadar A, Vrečer F, Kristl J. Development of floating tablets as a new approach to the treatment of Helicobacter pylori infections. Acta Pharm. 2001;51:21–33.
24. McConville P, Pope JM. H NMRT relexation in contact lens hydrogels as a probe of water mobility. Polymer. 2001;42:3559–3568. doi: 10.1016/S0032-3861(00)00714-X. [Cross Ref]
25. Tanaka T. Kinetics of phase transition in polymer gels. Physica. 1986;140A:261–268.

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