They have recently found favour as ‘solvents’ in which to
encapsulate poorly water-soluble drugs. At present, however, there is
little understanding as to the combinations of oil and surfactant that
are most effective for encapsulating drug. We have been using small
angle neutron scattering to perform the first studies to determine the
location of a range of steroidal drugs encapsulated within these
nanodispersions, with a view to determining the oil/surfactant
combinations best for drug delivery. We have used the technique of
neutron contrast variation by employing deuterated and hydrogenous oils
and surfactants. By fitting the neutron scattering results to models of
microemulsion shape and size, the location of the drugs within the
microemulsions has been deduced. At low steroid concentration, the drug
is preferentially located in the surfactant shell, while at higher
concentrations it enters the particle’s oil core – thus demonstrating
the importance of the oil in determining the level of drug
encapsulation.
MJ Lawrence, DJ Barlow (King’s College London), RK Heenan (ISIS)
Research date: December 2007
Further Information
MJ Lawrence and DJ Barlow (2006) in Encyclopedia of Pharmaceutical
Technology (Third Edition), J Swarbrick (Ed), Marcel Dekker Inc.
