Percolative drug diffusion from cylindrical matrix systems with unsealed boundaries
U. Brohede
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden
Search for more papers by this authorS. Valizadeh
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden
Search for more papers by this authorCorresponding Author
M. Strømme
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden. Telephone: +46-18-471-7231; Fax: +46-18-50-01-31Search for more papers by this authorG. Frenning
Department of Pharmacy, Uppsala Biomedical Center, Uppsala Univerity, P.O. Box 580, SE-751 23 Uppsala, Sweden
Search for more papers by this authorU. Brohede
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden
Search for more papers by this authorS. Valizadeh
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden
Search for more papers by this authorCorresponding Author
M. Strømme
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P. O. Box 534, SE-751 21 Uppsala, Sweden. Telephone: +46-18-471-7231; Fax: +46-18-50-01-31Search for more papers by this authorG. Frenning
Department of Pharmacy, Uppsala Biomedical Center, Uppsala Univerity, P.O. Box 580, SE-751 23 Uppsala, Sweden
Search for more papers by this authorAbstract
Release of NaCl in both the axial and radial directions from cylindrical ethyl cellulose tablets were investigated by the alternating ionic current method. The pore structure of the investigated binary mixtures was examined by mercury porosimetry and scanning electron microscopy, and the nm range fractal surface dimension of tablet pore walls was extracted from krypton gas adsorption isotherms. The drug release was shown to consist of two overlapping processes of which the first was ascribed to dissolution of NaCl close to the tablet boundary followed by subsequent diffusion through a thin ethyl cellulose layer and a second from which a porosity percolation threshold of 0.22 could be extracted. As well, a cross-over to effective-medium behaviour at a porosity of ∼0.44 was observed. The presented findings showed that drug release from matrix tablets with unsealed tablet walls substantially differs from earlier investigated release processes for which the drug has only been allowed to escape through one of the flat tablet surfaces. Thus, the present study brings forward knowledge important for the tailoring of controlled drug delivery vehicles with optimum release patterns. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 3087–3099, 2007
REFERENCES
- 1 G Alderborn, editor. 2002. Tablets and Compaction. New York: Churchill Livingstone. 397 p.
- 2
Agrawal AM,
Neau SH,
Bonate PL.
2003.
Wet granulation fine particle ethylcellulose tablets: Effect of production variables and mathematical modeling of drug release.
Aaps Pharmsci
5:
13.
10.1208/ps050213 Google Scholar
- 3 Fernández-Hervás MJ, Vela MT, Holgado MA, Delcerro J, Rabasco AM. 1995. Determination of percolation thresholds in matrix-type controlled-release systems—application of a resistance analysis technique. Int J Pharm 113: 39–45.
- 4 Leuenberger H, Bonny JD, Kolb M. 1995. Percolation effects in matrix-type controlled drug release systems. Int J Pharm 115: 217–224.
- 5 Shaikh NA, Abidi SE, Block LH. 1987. Evaluation of ethylcellulose as a matrix for prolonged release formulations .1. water-soluble drugs—acetaminophen and theophylline. Drug Dev Ind Pharm 13: 1345–1369.
- 6 Shaikh NA, Abidi SE, Block LH. 1987. Evaluation of ethylcellulose as a matrix for prolonged release formulations. 2. sparingly water-soluble drugs: Ibuprofen and indomethacin. Drug Dev Ind Pharm 13: 2495–2518.
- 7 Elarini SK, Leuenberger H. 1995. Modeling of drug-Release from polymer matrices—effect of drug loading. Int J Pharm 121: 141–148.
- 8 Bonny JD, Leuenberger H. 1991. Matrix type controlled release systems .1. Effect of percolation on drug dissolution kinetics. Pharm Acta Helv 66: 160–164.
- 9 Leuenberger H, Bonny JD, Kolb M. 1995. Percolation effects in matrix-type controlled drug-release systems. Int J Pharm 115: 217–224.
- 10 Ritger PL, Peppas NA. 1987. A simple equation for description of solute release I. Fickian and non-Fickian releasefrom non-swellable devices in the form of slabs, spheres, cylinders or discs. J Controlled Release 5: 23–36.
- 11 Korsmeyer RW, Gurny R, Doelker E, Buri P, Peppas NA. 1983. Mechanisms of solute release from porous hydrophilic polymers. Int J Pharm 15: 25–35.
- 12 Kosmidis K, Rinaki E, Argyrakis P, Macheras P. 2003. Analysis of Case II drug transport with radial and axial release from cylinders. Int J Pharm 254: 183–188.
- 13 Fu JC, Hagemeir C, Moyer DL, Ng EW. 1976. A unified mathematical model for diffusion from drug–polymer composite tablets. J Biomed Mater Res 10: 743–758.
- 14 Zhou Y, Chu JS, Zhou T, Wu XY. 2005. Modeling of dispersed drug release from two-dimensional matrix tablets. Biomaterials 2: 945–952.
- 15 Siepmann J, Peppas NA. 2000. Hydrophilic matrices for controlled drug delivery. An improved mathematical model to predict the resulting drug release kinetics the ‘sequential layer’ model. Pharm Res 17: 1290–1298.
- 16 Frenning G, Brohede U, Strømme M. 2005. Finite element analysis of the release of slowly dissolving drugs from cylindrical matrix systems. J Control Release 107: 320–329.
- 17 Wu XY, Zhou Y. 1999. Studies of diffusional release of a dispersed solute from polymeric matrixes by finite element method. J Pharm Sci-Us 88: 1050–1057.
- 18 Caraballo I, Fernández-Arévalo M, Holgado MA, Rabasco AM. 1993. Percolation theory: Application to the study of the release behaviour from inert matrix systems. Int J Pharm 96: 175–181.
- 19 Stauffer D, Aharony A. 1992. Introduction to Percolation Theory, 2nd ed. London: Taylor & Francis.
- 20 Kim H, Fassihi R. 1997. Application of a binary polymer system in drug release rate modulation .1. Characterization of release mechanism. J Pharm Sci-Us 86: 316–322.
- 21 Rinaki E, Valsami G, Macheras P. 2003. The power law can describe the 'entire' drug release curve from HPMC-based matrix tablets: A hypothesis. Int J Pharm 255: 199–207.
- 22 Kosmidis K, Argyrakis P, Macheras P. 2003. Fractal kinetics in drug release from finite fractal matrices. J Chem Phys 119: 6373–6377.
- 23 Jamzad S, Tutunji L, Fassihi R. 2005. Analysis of macromolecular changes and drug release from hydrophilic matrix systems. Int J Pharm 292: 75–85.
- 24
M Sahimi, editor.
1994.
Applications of Percolation Theory.
London: Taylor & Francis.
10.1201/9781482272444 Google Scholar
- 25 Schlotter NE. 1990. Diffusion of small molecules in glassy polymer thin-films studied by wave-guide Raman techniques. J Phys Chem-Us 94: 1692–1699.
- 26 Higuchi T. 1963. Theoretical analysis of rate of release of solid drugs dispersed in solid matrices. J Pharm Sci 52: 1145–1149.
- 27 Kirkpatrick S. 1973. Percolation and conduction. Rev Mod Phys 45: 574–588.
- 28 Wu JJ, McLachlan DS. 1997. Percolation exponents and thresholds obtained from the nearly ideal continuum percolation system graphite–boron nitride. Phys Rev B 56: 1236–1248.
- 29 Avnir D, Jaroniec M. 1989. An isotherm equation for adsorption on fractal surfaces of heterogeneous porous materials. Langmuir 5: 1431–1433.
- 30 Yin YB. 1991. Adsorption-isotherm on fractally porous materials. Langmuir 7: 216–217.
- 31 Pfeifer P, Wu YJ, Cole MW, Krim J. 1989. Multilayer adsorption on a fractally rough-surface. Phys Rev Lett 62: 1997–2000.
- 32 Kaneko K, Sato M, Suzuki T, Fujiwara Y, Nishikawa K, Jaroniec M. 1991. Surface fractal dimension of microporous carbon-fibers by nitrogen adsorption. J Chem Soc Faraday T 87: 179–184.
- 33 Vollet DR, Donatti DA, Ruiz AI. 2004. Comparative study using small-angle x-ray scattering and nitrogen adsorption in the characterization of silica xerogels and aerogels. Phys Rev B 69: 064202.
- 34 Friesen WI, Mikula RJ. 1987. Fractal dimensions of coal particles. J Colloid Interf Sci 120: 263–271.
- 35 Neimark A. 1992. A new approach to the determination of the surface fractal dimension of porous solids. Physica A 19: 258–262.
- 36 Sahouli B, Blacher S, Pirard R, Brouers F. 1999. Fractal analysis of mercury porosimetry data in the framework of the thermodynamic method. J Colloid Interf Sci 214: 450–454.
- 37 Zhang BQ, Li SF. 1995. Determination of the surface fractal dimension for porous-media by mercury porosimetry. Ind Eng Chem Res 34: 1383–1386.
- 38 Usteri M, Bonny JD, Leuenberger H. 1990. Fractal dimension of porous solid dosage forms. Pharm Acta Helv 65: 55–61.
- 39 Bonny JD, Leuenberger H. 1993. Determination of fractal dimensions of matrix-type solid dosage forms and their relation with drug dissolution kinetics. Eur J Pharm Biopharm 39: 31–37.
- 40 Ismail IMK, Pfeifer P. 1994. Fractal analysis and surface roughness of nonporous carbon fibers and carbon blacks. Langmuir 10: 1532–1538.
- 41 Frenning G, Ek R, Strømme M. 2002. A new method for characterizing the release of drugs from tablets in low liquid surroundings. J Pharm Sci 91: 776–784.
- 42 DR Lide, editor. 1999. CRC Handbook of Chemistry and Physics: A Ready-Reference Book of Chemical and Physical Data, 80th ed. Cleveland, OH: CRC Press.
- 43 Frenning G, Strømme M. 2003. Drug release from tablets modeled by dissolution, diffusion, and immobilization caused by adsorption of the drug to the tablet constituents. Int J Pharm 250: 137–145.
- 44 Noyes AA, Whitney W. 1897. Auflösungsgeschwindigkeit von festen Stoffen in ihren eigenen Lösungen. Z P Chem 23: 689.
- 45 Soriano MC, Caraballo I, Millan M, Pinero RT, Melgoza LM, Rabasco AM. 1998. Influence of two different types of excipient on drug percolation threshold. Int J Pharm 174: 63–69.
- 46 Neigo P. 1996. Diffusion in Polymers. New York: Marcel Dekker. pp 37–154.
- 47 Wu XY, Zhou Y. 1998. Finite element analysis of diffusional drug release from complex matrix systems II Factors influencing release kinetics. J. Controlled Release 51: 57–71.
- 48 Brohede U, Strømme M. 2006. Percolating ion transport in binary mixtures with high dielectric loss. Appl Phys Lett 88: 214103.
- 49 Webb PA, Orr C. 1997. Analytical Methods in Fine Particle Technology, 1st ed. Norcross, GA 30093, USA: Micromeritics Instrument Corp.
- 50 van Veen B, Maarschalk KvdV, Bolhuis GK, Visser MR, Zuurman K, Frijlink HW. 2002. Pore formation in tablets compressed from binary mixtures as a result of deformation and relaxation of particles. Eur J Pharm Sci 15: 171–177.
- 51 Kelvin WT. 1871. On the equilibrium of vapour at a curved surface of liquid. Philos Mag 42: 448–452. (published under the name of Sir William Thomson).
