Læknablaðið : fylgirit - 03.01.2017, Side 81

X V I I I V Í S I N D A R Á Ð S T E F N A H Í
F Y L G I R I T 9 1
LÆKNAblaðið/Fylgirit 91 2017/103 81
for layer-by-layer modification of PP and PLA nonwovens. The bacterici-
dal effect of the three modified nonwovens towards S. aureus, expressed in
terms of percentage reduction of the viable bacterial cells show that PP-1
showed a reduction of upto ~60% after 4.5 h in comparison to the growth
control. On the other hand, PP-2 and PLA were capable of showing 100%
reduction in the bacterial cells at time intervals of 2 h and 3 h respectively
and this effect was maintained up to the end of 24 h.
Conclusion: The deposition of TMC layer contributes antibacterial
properties to modified polypropylene and polylactide materials which
can be used for medical applications.
V 64 Aggregation of native β-cyclodextrin (βCD) and HP-β-
cyclodextrin (HPβCD): determination of critical aggregation
concentration by permeation
André Sá Couto, Ryzhakov Alexey, Þorsteinn Loftsson
Faculty of Pharmacy University Iceland
ars70@hi.is
Introduction: Purpose of the present work was to investigate formation of
aggregates in aqueous βCD and HPβCD solutions using CD permeation
through semi-permeable cellophane membranes. Another goal was
to calculate the lowest CD concentration that initiates the aggregation
process (i.e. the critical aggregation concentration [cac]).
Methods and data: Aqueous βCD and HPβCD solutions of vari-
ous concentrations were prepared through sonication (60°C, 60 min).
All concentrations were determined by UHPLC validated methods.
Permeation studies were carried out in unjacketed Franz diffusion cells
using semipermeable membranes with molecular-weight-cutoff (MWCO)
of 3.5-5 and 8-10kDa.
Results: Regarding to the βCD permeation studies a negative deviation
from the theoretical flux curve was observed for the MWCO 3.5-5 kDa
membrane but close to linear relationship was observed for the MWCO
8-10kDa membrane. Similar results were obtained for HPβCD where the
MWCO 3.5-5 kDa membrane indicated HPβCD aggregation. From the
intersection of the linear portions of the plots at concentrations above
and below the inflections points it was possible to determine CAC for
both CDs. The calculated CAC for βCD was approximately 1.1% and for
HPβCD approximately 15%.
Conclusions: The analysis of permeation results for both CD clearly
indicates that the aggregates are 5-10kDa as they seem to permeate freely
through the 8-10kDa pore size membrane (linear flux) but not through
the 3.5-5kDa membrane. The aggregation and aggregate size appeared to
increase with increasing CD concentration. One can conclude that HPβCD
(CAC 15% w/v) has less tendency to form aggregates than the native βCD
(CAC 1.1% w/v).
V 65 Interaction of 2-hydroxypropyl-β-cyclodextrin (HPβCD) with
parabens: influence in the aggregation process
André Sá Couto, Ryzhakov Alexey, Þorsteinn Loftsson
Faculty of Pharmacy University Iceland
ars70@hi.is
Purpose: Purpose of the present work was to investigate the influence
of parabens on HPβCD aggregation by permeation and determine their
effect on the critical aggregation concentration (cac) of HPβCD.
Methods: Binary systems of HPβCD and parabens (i.e. methyl-, ethyl-,
propyl- or butylparaben) of various concentrations were prepared in
aqueous solutions. Permeation studies were carried out in unjacketed
Franz diffusion cells using semipermeable membranes with molecular-
-weight-cutoff (MWCO) of 3.5-5 kDa.
Results: Analysis of pure aqueous HPβCD solutions showed negati-
ve deviation from linearity at elevated HPβCD concentrations and cac
of approximately 15% w/v. HPβCD solutions containing methyl- and
ethylparaben gave similar HPβCD flux profiles (similar slopes) as pure
HPβCD solution showing that these two parabens have negligible effect
on the cac of HPβCD (cac 14-15%). In contrast, propyl- and butylparaben
decreased the HPβCD flux indicating that these parabens have signi-
ficant effect on HPβCD cac (≈12%). Regarding the cac of the parabens,
methylparaben gives a linear flux-paraben concentration profile (cac
cannot be observed in the study range) while the remaining parabens
display a negative deviation from linearity (increased with the increasing
length of the alkyl chain).
Conclusion: As previously described parabens can self-aggregate and
aggregation increased with increasing alkyl chain length (MP < EP < PP <
BP). One can also conclude that methyl- and ethylparaben do not influence
HPβCD flux profile (similar cac) while propyl- and butylparaben increa-
sed HPβCD aggregation. HPβCD (cac ≈15% w/v) had higher tendency to
form aggregates in presence of propyl- and butylparaben (cac ≈ 12% w/v).
V 66 Transdermal numerical modelling from silicone matrix systems
Bergþóra S. Snorradóttir1, Fjóla Jónsdóttir2, Sven Th. Sigurðsson2, Már Másson1
1Faculty of Pharmaceutical Science, University of Iceland, 2Faculty of Industrial Engineering,
Mecha, University of Iceland
bss@hi.is
Introduction: Matrix type formulations are common types of delivery
systems used for transdermal delivery. Modelling was used to find para-
meter values for the matrix systems, based on release studies, and for the
membranes by an investigation of trans-membrane delivery from donor
solutions.
Methods and data: Transdermal drug release, in vitro studies from donor
solutions and silicone matrix systems were conducted with vertical Franz
diffusion cells. A numerical model was constructed. The model was transi-
ent and did not require pseudo-steady state approximation. It was vali-
dated against experimental data for drug release from silicone matrices.
Results: The model was transient and could therefore be used to pred-
ict lag-times in addition to the drug flux for trans-dermal delivery. The
donor solution drug release considered conditions where there were no
diffusion limitations, contrary to the cases of drug incorporated silicone
matrix systems. Good fit to experimental data was obtained.
Conclusions: The modelling approach was illustrated by allowing
the possibility of a donor solution. The results indicated that while the
dissolution in the case of ibuprofen is close to being instantaneous, this is
not so in the case of diclofenac. The experiments and the numerical model
outlined in this study could also be adjusted to more general formulations.
V 67 Inclusion complex formation of p-hydroxybenzoic acid esters
and ϒ-Cyclodextrin
Phennapha Saokham1, Þorsteinn Loftsson2
1Faculty of Pharmaceutical Sciences, University of Iceland, 2University of Iceland
phs3@hi.is
Introduction: The usage of parabens in aqueous media has been hamper-