AAPS PharmSciTech

, Volume 7, Issue 1, pp E43–E48 | Cite as

Local and average gloss from flat-faced sodium chloride tablets

  • Mikko Juuti
  • Bert van Veen
  • Kai-Erik Peiponen
  • Jarkko Ketolainen
  • Valtteri Kalima
  • Raimo Silvennoinen
  • Tuula T. Pakkanen


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.


gloss tablet surface structure sodium chloride 


  1. 1.
    Wagberg P, Johansson P-Å. Surface profilometry: a comparison between optical and mechanical sensing on printing papers. Tappi J. 1993;76:115–121.Google Scholar
  2. 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.Google Scholar
  3. 3.
    Seitavuopio P, Rantanen J, Yliruusi J. Tablet surface characterisation by various imaging techniques. Int J Pharm. 2003;254:281–286.CrossRefPubMedGoogle Scholar
  4. 4.
    Hunter RS, Harold RW. The Measurement of Appearance. New York, NY: Wiley; 1987.Google Scholar
  5. 5.
    Rowe RC. Gloss measurement on film coated tablets. J Pharm Pharmacol. 1985;37:761–765.CrossRefPubMedGoogle Scholar
  6. 6.
    Rohera BD, Parikh NH. Influence of plasticizer type and coat level on Surelease® film properties. Pharm Dev Technol. 2002;7:407–420.CrossRefPubMedGoogle Scholar
  7. 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.CrossRefGoogle Scholar
  8. 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.CrossRefGoogle Scholar
  9. 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.CrossRefPubMedGoogle Scholar
  10. 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.CrossRefPubMedGoogle Scholar
  11. 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.Google Scholar
  12. 12.
    Nieto-Vesperinas M. Scattering and Diffraction in Physical Optics. New York, NY: Wiley; 1991.Google Scholar
  13. 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.CrossRefGoogle Scholar
  14. 14.
    Silvennoinen R, Peiponen K-E, Asakura T. Diffractive optical elements in materials inspection. In: Asakura T, ed. International Trends in Optics and Photonics ICO IV. Heidelberg, Germany: Springer; 1999.Google Scholar
  15. 15.
    Palik ED. Handbook of Optical Constants of Solids. Vol. 1. London, England: Academic Press; 1998.Google Scholar
  16. 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.CrossRefPubMedGoogle Scholar
  17. 17.
    Roberts RJ, Rowe RC, Kendall K. Brittle-ductile transitions in die compaction of sodium chloride. Chem Eng Sci. 1989;44: 1647–1651.CrossRefGoogle Scholar

Copyright information

© American Association of Pharmaceutical Scientists 2006

Authors and Affiliations

  • Mikko Juuti
    • 1
  • Bert van Veen
    • 2
  • Kai-Erik Peiponen
    • 1
  • Jarkko Ketolainen
    • 3
  • Valtteri Kalima
    • 4
  • Raimo Silvennoinen
    • 1
  • Tuula T. Pakkanen
    • 4
  1. 1.Department of PhysicsUniversity of JoensuuJoensuuFinland
  2. 2.Orion Pharma R&DOrion CorporationTurkuFinland
  3. 3.Department of PharmaceuticsUniversity of KuopioKuopioFinland
  4. 4.Department of ChemistryUniversity of JoensuuJoensuuFinland

Personalised recommendations