Supplementary material
Insights into the role of polymer-surfactant complexes in drug solubilisation/stabilisation during drug release from solid dispersions
Sheng Qi[1],5, Steve Roser[2], Karen J. Edler2, Claudia Pigliacelli, Madeleine Rogerson1, Ilse Weuts[3], Frederic Van Dycke4
Correspondence: Sheng Qi,
List of contents
1. Method description of the pendant drop measurements performed
2. Table 1 Comparison of the surface tension results obtained from Wilhelmy plate method and pendant drop method
3. Figure 1 The kinetic profile of the interfacial tension of polymer-surfactant solutions measured using pedant drop method.
4. SANS results of Tween 20 solutions containing HPMC
1. Method
Pendant drop measurements
The surface tension measurements were performed using the pendant drop technique with a FT200 drop tensiometer (First TenAn Angstroms, Portsmouth, VA). Aninvertedair bubble was formed at the tip of a 1.32 diameter (external) u-shaped needle fitted to a syringe with total volume of 100µL. The bubble was formed in a glass cuvette filled with 4 ml of HPMC 0.025% w/v at room temperature. Bile salts and SDS were gradually added to the HPMC solution. The air/liquid interfacial tension was recorded for 10-15 minutes.
Table 1 Comparison of the surface tension results obtained from Wilhelmy plate method and pendant drop method
Samples / Surface tension (mN/m)Measured by Wilhelmy plate / Interfacial tension (mN/m)
Measured by pendent drop
HPMC 0.025% w/v + SDS 0.08%w/v / 37.2 / 42.5
HPMC 0.025% w/v +SDS 0.4%w/v / 34 / 34.0
HPMC 0.025% w/v + Bile salts 0.08% w/v / 47 / 44.1
HPMC 0.025% w/v + Bile salts 0.25% w/v / 43 / 41.8
Figure 1 The kinetic profile of the interfacial tension of polymer-surfactant solutions measured using pedant drop method.
These results indicate that the time required to reach equilibrium is within 5 minutes. This finding validates the surface tension measurements taken using the Wilhelmy plate method with a 15 minutes equilibrium time.
Figure 2 SANS results of Tween 20 solutions containing HPMC
These results indicate a very low level of scattering, thus do not provide evidence for the presence of polymer-surfactant complexes occurring between HPMC E5 and Tween 20.
1
[1] School of Pharmacy, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
[2] School of Chemistry, University of Bath, Bath, BA2 7AY, UK
[3] Pharmaceutical Research and Development, Johnson & Johnson, Beerse, Belgium
4 SEPS Pharma, Gent, Belgium
5 To whom correspondence should be addressed. Mailing address: School of Pharmacy, University of East Anglia, Norwich, NR4 7TJ, UK. Phone: (44) 1603 592925. Fax: (44) 1603 592015. E-mail: