Advertisement

Factors Affecting Adhesion of Drug Particles to Surfaces in Pharmaceutical Systems

  • P. J. Stewart

Abstract

The mechanism of adhesion of drug powders on the surface of polymer coated glass beads was studied. Glass beads (500 µm) were air suspension coated using a 5% hydroxypropylmethylcellulose phthalate solution in dichloromethane: methanol solvent (50:50). Specific particle size fractions of several sulphonamide powders were prepared by fluid energy milling and sonic sifting; distributions were characterized by laser diffraction. Average charge to mass ratios on particle detachment were measured using an air stream Faraday cage. Total adhesion was determined by a centrifugal method and characterized by an S50 value, i.e. the speed required to detach 50% of the drug particles. Electrical interactions probably caused by triboelectrification during the preparation of the interactive system contributed significantly to the initial drug adhesion. Adhesion decreased with time and was well correlated with the charge to mass ratio decrease. The rate of decrease in adhesion increased with increasing relative humidity. Adhesion did not occur uniformly over the polymer surface with local multilayer adsorption occurring when the drug concentration was increased. When the interactive systems were prepared at higher relative humidity conditions (60% RH), adhesion between the drug particles and surface was significantly decreased; non-electrical interactions contributed to the adhesion process under these conditions.

Keywords

Liquid Bridge Drug Particle Average Charge Particle Layer Carrier Surface 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    P.Kulvanich and P.J. Stewart, Fundamental considerations in the measurement of adhesional forces between particles using the centrifuge method. Int. J. Pharm., 35, 111–120 (1987).CrossRefGoogle Scholar
  2. 2.
    P.Kulvanich and P.J. Stewart, An evaluation of the air stream Faraday cage in the electrostatic charge measurement of interactive drug systems. Int. J. Pharm., 36, 243–252 (1987).CrossRefGoogle Scholar
  3. 3.
    P.Kulvanich and P.J. Stewart, Influence of relative humidity on the adhesive properties of a model interactive system. J. Pharm. Pharmacol., 40, 453–458 (1988).CrossRefGoogle Scholar
  4. 4.
    H.Krupp, Particle adhesion: Theory and experiment. Adv. Colloid Interface Sci., 1, 111–239 (1967).CrossRefGoogle Scholar
  5. 5.
    B.V.Derjaguin, Yu.P.Toporov, V.M. Muller, and I.E. Aleinikova, On the relationships between the electrostatic and the molecular component of the adhesion of elastic particles to a solid surface. J. Colloid Interface Sci., 58, 528–533 (1977).CrossRefGoogle Scholar
  6. 6.
    I.E.Aleinikova, B.V.Derjaguin and Yu.P.Toporov, The electrostatic component of adhesion of dielectric pajrticles to a metal surface. Kolloidn. Zh., 30, 177–182 (1968).Google Scholar
  7. 7.
    P.Kulvanich and P.J.Stewart, Correlation between total adhesion and charge decay of a model interactive system during storage. Int. J. Pharm., 39, 51–57 (1987).CrossRefGoogle Scholar
  8. 8.
    A.D. Zimon, “Adhesion of Dust and Powder”, 2nd ed., pp. 108–119, Consultants Bureau, New York, 1982.Google Scholar
  9. 9.
    E.N.Hiestand, Powders: Particle — particle interactions. J. Pharm. Sci., 55, 1325–1344 (1966).CrossRefGoogle Scholar
  10. 10.
    G.A.Turner and M.Balasubramanian, The frequency distributions of electrical charges on glass beads. J. Electrostat., 2, 85–89 (1976).CrossRefGoogle Scholar
  11. 11.
    W.J. Whitfield, A study of the effects of relative humidity on small particle adhesion to surfaces, in “Surfade Contamination: Genesis, Detection and Control”, K.L.Mittal, editor, Vol. 1, pp. 73–81, Plenum Press, New York, 1979.Google Scholar

Copyright information

© Plenum Press, New York 1989

Authors and Affiliations

  • P. J. Stewart
    • 1
  1. 1.Department of PharmacyUniversity of QueenslandQueenslandAustralia

Personalised recommendations