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AAPS PharmSciTech. 2006 March; 7(1): E43–E48.
Published online 2006 January 13. doi:  10.1208/pt070107
PMCID: PMC2750714

Local and average gloss from flat-faced sodium chloride tablets


The purpose of this study was to detect local gloss and surface structure changes of sodium chloride tablets. The changes in surface structure were reflected by gloss variation, which was measured using a diffractive optical element-based gloss-meter (DOG). By scanning a surface area, we constructed a 2-dimensional gloss map that characterized the tablet’s surface structure. The gloss variation results were compared with scanning electron microscopy (SEM) images and average surface roughness values that were measured by conventional diamond stylus profilometry. The profilometry data showed a decrease in tablet surface roughness as a function of compression force. In general, a smoother surface contributes to higher average gloss values. The average gloss values for this material, in contrast, showed a decrease as a function of the compression force. The sequence of particle fragmentation and deformation together with crack formation in sodium chloride particles resulted in a loss of gloss for single sodium chloride particles at the tablet surfaces, which could be detected by the DOG. These results were supported by the SEM images. The results show that detailed information regarding tablets’ surface structure changes can be obtained by detection of local gloss variation and average gloss.

Keywords: gloss, tablet, surface structure, sodium chloride

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
1. Wagberg P, Johansson P-Å. Surface profilometry: a comparison between optical and mechanical sensing on printing papers. Tappi J. 1993;76:115–121.
2. Podczek F. Measurement of surface roughness of tablets made from polyethylene glycol powders of various molecular weight. Pharm Pharmacol Commun. 1998;4:179–182.
3. Seitavuopio P, Rantanen J, Yliruusi J. Tablet surface characterisation by various imaging techniques. Int J Pharm. 2003;254:281–286. doi: 10.1016/S0378-5173(03)00026-7. [PubMed] [Cross Ref]
4. Hunter RS, Harold RW. The Measurement of Appearance. New York, NY: Wiley; 1987.
5. Rowe RC. Gloss measurement on film coated tablets. J Pharm Pharmacol. 1985;37:761–765. [PubMed]
6. Rohera BD, Parikh NH. Influence of plasticizer type and coat level on Surelease® film properties. Pharm Dev Technol. 2002;7:407–420. doi: 10.1081/PDT-120015043. [PubMed] [Cross Ref]
7. Myller K, Peiponen K-E, Silvennoinen R. Two-dimensional map of gloss of plastics measured by diffractive element based glossmeter. Opt Eng. 2003;42:3194–3197. doi: 10.1117/1.1614263. [Cross Ref]
8. Silvennoinen R, Myller K, Peiponen K-E, Salmi J, Pääkkönen EJ. Diffractive optical sensor for gloss differences of injection molded plastic products. Sensors Actuators A. 2004;112:74–79. doi: 10.1016/j.sna.2003.12.016. [Cross Ref]
9. Hyvärinen V, Peiponen K-E, Silvennoinen R, Raatikainen P, Paronen P, Niskanen T. Optical inspection of punches: flat surfaces. Eur J Pharm Biopharm. 2000;49:87–90. doi: 10.1016/S0939-6411(99)00062-4. [PubMed] [Cross Ref]
10. Hyvärinen V, Silvennoinen R, Peiponen K-E, Niskanen T. Diffractive optical element based sensor for surface quality inspection of concave punches. Eur J Pharm Biopharm. 2000;49:167–169. doi: 10.1016/S0939-6411(99)00071-5. [PubMed] [Cross Ref]
11. Peiponen K-E, Alarousu E, Juuti M, et al. Diffractive optical element based glossmeter and low coherence interferometer in assessment of local surface quality of paper. Opt Eng. In press.
12. Nieto-Vesperinas M. Scattering and Diffraction in Physical Optics. New York, NY: Wiley; 1991.
13. Silvennoinen R, Räsänen J, Savolainen M, Peiponen K-E, Uozumi J, Asakura T. On simultaneous optical sensing of local curvature and roughness of metal surface. Sensors Actuators A. 1996;51:117–123. doi: 10.1016/0924-4247(95)01207-9. [Cross Ref]
14. Silvennoinen R, Peiponen K-E, Asakura T. Diffractive optical elements in materials inspection. In: Asakura T, editor. International Trends in Optics and Photonics ICO IV. Heidelberg, Germany: Springer; 1999.
15. Palik ED. Handbook of Optical Constants of Solids. London, England: Academic Press; 1998.
16. van Veen B, van der Voort Maarschalk K, Bolhuis GK, Zuurman K, Frijlink HW. Tensile strength of tablets containing two materials with a different compaction behavior. Int J Pharm. 2000;203:71–79. doi: 10.1016/S0378-5173(00)00450-6. [PubMed] [Cross Ref]
17. Roberts RJ, Rowe RC, Kendall K. Brittle-ductile transitions in die compaction of sodium chloride. Chem Eng Sci. 1989;44:1647–1651. doi: 10.1016/0009-2509(89)80007-7. [Cross Ref]

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