Pharmaceutisch Weekblad

, Volume 4, Issue 5, pp 117–121 | Cite as

Drug release from non-aqueous suspensions

I. Release of phenobarbital and phenobarbital sodium from paraffin suspensions
  • J. G. Fokkens
  • C. J. De Blaey
Original Articles


The rate at which phenobarbital and phenobarbital sodium, suspended in liquid paraffin, are released to buffers pH=3.o, 7.4 and 10.0 has been studied. The release rate of phenobarbital depends on its solubility and hence on the pH, whereas the initial release rate of phenobarbital sodium is governed by sedimentation and hence is independent of the pH. However, when phenobarbital sodium is released to buffer pH=3.0, it crystallizes in the interfacial layer after an initial release time. The release process in the release apparatus used cannot be described by a theory based on forced convection [i.e. the(e)scrd-theory], but has to be regarded as a natural convection process.


Internal Medicine Paraffin Release Rate Drug Release Natural Convection 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Crommelin, D.J.A., andC.J. De Blaey (1980a)Int. J. Pharm. 5, 305–316;Ibidem (1980b)6, 29–42.Google Scholar
  2. Fokkens, J.G., and C.J.De Blaey (1982) In preparation.Google Scholar
  3. Grijseels, H., D.J.A. Crommelin andC.J. De Blaey (1981)Pharm. Weekblad Sci. Ed. 3, 129–144.Google Scholar
  4. Higuchi, W.I., E.L. Parrott, D.E. Wurster andT. Higuchi (1958)J. Am. Pharm. Assoc. Sci. Ed. 47, 376–383.Google Scholar
  5. Higuchi, W.I., E. Nelson andJ.G. Wagner (1964)J. Pharm. Sci. 53, 333–335.Google Scholar
  6. The Extra Pharmacopoeia (1973) 26th Edition. The Pharmaceutical Press, London, XXI.Google Scholar
  7. Merck Index (1976) Ninth edition. Merck & Co. Inc., Rayway, NJ, USA, 939–940.Google Scholar
  8. Mooney, K.G., M.A. Mintun, K.J. Himmelstein andV.J. Stella (1981)J. Pharm. Sci. 70, 13–32.Google Scholar
  9. Nogami, H., T. Nagai andT. Yotsuyanagi (1969)Chem. Pharm. Bull. 17, 499–509.Google Scholar
  10. Schoonen, A.J.M., F. Moolenaar andT. Huizinga (1979)Int. J. Pharm. 4, 141–152.Google Scholar
  11. Schoonen, A.J.M., F. Moolenaar, K.A. Reuvers andT. Huizinga (1980)Int. J. Pharm. 7, 29–43.Google Scholar

Copyright information

© Royal Dutch Association for Advancement of Pharmacy 1982

Authors and Affiliations

  • J. G. Fokkens
    • 1
  • C. J. De Blaey
    • 1
  1. 1.Department of Pharmaceutics, Pharmaceutical LaboratoryUniversity of UtrechtGH UtrechtThe Netherlands

Personalised recommendations