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An atomic force microscopy approach for assessment of particle density applied to single spray-dried carbohydrate particles
Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
2007 (English)In: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017, Vol. 96, no 4, 905-912 p.Article in journal (Refereed) Published
Abstract [en]

To evaluate an atomic force microscopy (A-FM) approach for effective density analysis of single spray dried carbohydrate particles in order to investigate the internal structure of the particles. In addition, the AFM method was compared to an established technique, that is gas pycnometry. Resonant frequency AFM analysis was employed for determination of the mass of individual particles of spray-dried lactose, mannitol, and a mixture of sucrose/dextran (4:1). The effective particle density was calculated using the diameter of the spherical particles obtained from light microscopy. The apparent particle density was further analyzed with gas pycnometry. It was observed by microscopy that particles appeared either ""solid"" or ""hollow."" A solid appearance applied to an effective particle density close to the true density of the material, whereas a density around 1 g/cm(3) corresponded to a hollow appearance. However, carbohydrates, which crystallized during spray drying, for example, mannitol appeared solid but the 3 average effective particle density was 0.95 g/cm, indicating a continuous but porous structure. AFM measurements of effective particle density corroborate the suggestion of differences in particle structure caused by the varying propensity of carbohydrates to crystallize during spray drying, resulting in mainly either amorphous hollow or crystalline porous particles.

Place, publisher, year, edition, pages
2007. Vol. 96, no 4, 905-912 p.
Keyword [en]
particle density, atomic force microscopy (AFM), gas pycnometry, microparticles, spray drying, morphology, crystallization, amorphous
National Category
Chemical Sciences
URN: urn:nbn:se:su:diva-56578DOI: 10.1002/jps.20795ISI: 000245426900016OAI: diva2:411949
authorCount :3Available from: 2011-04-20 Created: 2011-04-19 Last updated: 2011-04-20Bibliographically approved

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