Abstract
Purpose
The phase composition and distribution of ethylcellulose (EC) films containing varying amounts of the plasticizer fractionated coconut oil (FCO) were studied using a novel combination of thermal and mapping approaches.
Methods
The thermal and thermomechanical properties of films containing up to 30% FCO were characterized using modulated temperature differential scanning calorimetry (MTDSC) and dynamic mechanical analysis (DMA). Film surfaces were mapped using atomic force microscopy (AFM; topographic and pulsed force modes) and the composition of specific regions identified using nanothermal probes.
Results
Clear evidence of distinct conjugate phases was obtained for the 20–30% FCO/EC film systems. We suggest a model whereby the composition of the distinct phases may be estimated via consideration of the glass transition temperatures observed using DSC and DMA. By combining pulsed force AFM and nano-thermal analysis we demonstrate that it is possible to map the two separated phases. In particular, the use of thermal probes allowed identification of the distinct regions via localized thermomechanical analysis, whereby nanoscale probe penetration is measured as a function of temperature.
Conclusion
The study has indicated that by using thermal and imaging techniques in conjunction it is possible to both identify and map distinct regions in binary films.
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References
Repka MA, Majumdar S, Battu SK, et al. Applications of hot-melt extrusion for drug delivery. Exp Opinion Drug Del. 2008;5(12):1357–76.
Rajabi-Siahboomi AR, Farrell TP. The applications of formulated systems for the aqueous film coating of pharmaceutical oral solid dosage forms. In: Felton L, McGinity J, editors. Aqueous polymeric coatings for pharmaceutical dosage forms. 3rd ed. New York: Informa Healthcare; 2008. pp. 323–344.
Gordon M, Taylor JS. Ideal polymers and the second-order transitions of synthetic rubbers: non-crystalline copolymers. Journal of Application Chemistry. 1952;2:493–500.
Marcilla A, Beltran M. Mechanisms of plasticizers action. In: Wypych G, editor. Handbook of plasticizers. Toronto: ChemTec Publishing; 2004. p. 107–21.
Sears JK, Darby JR. Technology of plasticizers. New York: John Wiley and Sons; 1982.
Fox TG, Flory PJ. Second-order transition temperatures and related properties of polystyrene. J Appl Phys. 1950;21:581–91.
Flory PJ. Principles of polymer chemistry. Thaca, New York: Cornell University Press; 1953.
DiPaola-Baranyi G, Guillet JE. Estimation of polymer solubility parameters by gas-chromatography. Macromolecules. 1978;11:228–35.
Qi S, Belton P, Nollenberger K, Clayden N, Reading M, Craig DQM. Characterisation and prediction of phase separation in hot-melt extruded solid dispersions: a thermal, microscopic and NMR relaxometry study. Pharm Res. 2010;27(9):1869–83.
Widjaja E, Kanaujia P, Lau G, Ng WK, Garland M, Saal C, Hanefeld A, Fischbach M, Maio M, Tan RBH. Detection of trace crystallinity in an amorphous system using raman microscopy and chemometric analysis. Eur J Pharm Sci. 2011;42(1–2):45–54.
Qi S, Gryczke A, Belton P, Craig DQM. Characterisation of solid dispersions of paracetamol and eudragit (R) E prepared by hot-melt extrusion using thermal, microthermal and spectroscopic analysis. Int J Pharm. 2008;354(1–2):158–67.
Lai H-L, Pitt Kl, Craig DQM. Characterisation of the thermal properties of ethylcellulose using differential scanning and quasi-isothermal calorimetric approaches. Int J Pharm. 2010;386:178–84.
Bheda J, Fellers JF, White JL. Phase-behaviour and structure of liquid crystalline solutions of cellulose dderivatives colloid. Polym Sci. 1980;258:1335–42.
Harding L, King WP, Dai X, Craig DQM, Reading M. Nanoscale characterisation and imaging of partially amorphous materials using local thermomechanical analysis and heated tip AFM. Pharm Res. 2007;24(11):2048–54.
Nelson BA, King WP. Measuring material softening with nanoscale spatial resolution using heated silicon probes. Rev Sci Instrum. 2007;78(2):023702.
Harding L, Wood J, Reading M, Craig DQM. Two- and three-dimensional imaging of multicomponent systems using scanning thermal microscopy and localized thermomechanical analysis. Anal Chem. 2007;79(1):129–39.
Hammiche A, Bozec L, Pollock HM, German M, Reading M. Progress in near-field photothermal infra-red microspectroscopy. J Microsc Oxford. 2004;213:129–34.
Mrklic Z, Rusic D, Kovacic T. Kinetic model of the evaporation process of benzylbutyl phthalate from plasticized poly(vinyl chloride). Thermochim Acta. 2004;414(2):167–75.
Reading M, Luget A, Wilson R. Modulated differential scanning calorimetry. Thermochim Acta. 1994;238:295–307.
Baiardo M, Frisoni G, Scandola M, Rimelen M, Lips D, Ruffieux K, Wintermantel E. Thermal and mechanical properties of plasticized poly(L-lactic acid). J Appl Polym Sci. 2003;90:1731–8.
Okamoto K, Ichikawa T, Yokohara T, Yamaguchi M. Miscibility, mechanical and thermal properties of poly(lactic acid)/polyester-diol blends. Eur Polym J. 2009;45:2304–12.
Jia Z, Tan J, Han C, Yang Y, Dong L. Poly(ethylene glycol-co-propylene glycol) as a macromolecular plasticizing agent for polylactide: thermomechanical properties and aging. J Appl Polym Sci. 2009;114:1105–17.
Senichev VY, Tereshatov VV. Theories of compatibility. In: Wypych G, editor. Handbook of plasticizers. Toronto: ChemTec Publishing; 2004. p. 121–50.
Lodge TP, McLeish TCB. Self-concentrations and effective glass transition temperatures in polymer blends. Macromolecules. 2000;33:5278–84.
Lodge TP, Wood ER, Haley JC. Two calorimetric glass transitions do not necessarily indicate immiscibility: the case of PEO/PMMA. J Polym Sci, Part B: Poly Phys. 2006;44:756–63.
Simha R, Boyer RF. On a general relation involving the glass temperature and efficients of expansion of polymers. J Chem Phys. 1962;37:1003–7.
Meincken M, Sanderson RD. Determination of the influence of the polymer structure and particle size on the film formation process of polymers by atomic force microscopy. Polymer. 2002;43(18):4947–55.
Song M, Hourston DJ, Grandy DB, Reading M. An application of micro-thermal analysis to polymer blends. J Appl Polym Sci. 2001;81:2136–41.
Royall PG, Kett VL, Andrews CS, Craig DQM. Identification of crystalline and amorphous regions in low molecular weight materials using microthermal analysis. J Phys Chem B. 2001;105:7021–6.
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We would like to thank Colorcon Ltd. for financial support.
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Meng, J., Levina, M., Rajabi-Siahboomi, A.R. et al. The Development of Thermal Nanoprobe Methods as a Means of Characterizing and Mapping Plasticizer Incorporation into Ethylcellulose Films. Pharm Res 29, 2128–2138 (2012). https://doi.org/10.1007/s11095-012-0742-4
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DOI: https://doi.org/10.1007/s11095-012-0742-4