Development of an in vitro Endotoxin Test for
Monoolein–Water Liquid Crystalline Gel for Use as an
Moustapha Ouédraogo1*, Rasmané Semdé1,
Issa T Somé1, Moussa Ouédraogo1,
Rasmata Ouédraogo1, Viviane Henschel2,
Brigitte Evrard3, Jacques Dubois2,
Karim Amighi2 and Innocent P Guissou1
- Sciences de la Santé, Université de Ouagadougou, 03 BP
7021 Ouagadougou 03, Burkina Faso, 2Pharmacy
Institute, Université Libre de Bruxelles, Campus Plaine,
Boulevard du Triomphe, B 1050 Bruxelles, 3Pharmacy
Institute, Université de Liège, CHU Tour 4, Av. de
l’Hôpital, B 4000 Liège 1, Belgium.
Received: 27 March 2009
Revised accepted: 20 September 2009
Journal of Pharmaceutical Research, December 2009; 8(6):
Drugs that are administered by parenteral route must be
apyrogenic. The aim of this study was to develop an in
vitro endotoxin test for liquid crystalline gels for use
as implants, using a monoolein–water liquid crystalline
gel as a model.
The gel-clot technique was used. The gel was dissolved
first in isopropyl myristate, and the endotoxins were
extracted with water for bacterial endotoxin test. Tests
for the labelled lysate sensitivity and interfering
factors were performed to validate the developed method.
The limit of detection of endotoxin in the gel was also
The labelled lysate sensitivity was confirmed. It was
not influenced by the presence of extracts from the
gels. Endotoxins in the contaminated test gels were
completely extracted. Endotoxin concentration in the
tested gels was below the calculated threshold endotoxin
A method to perform in vitro endotoxins test of liquid
crystalline gels was successfully developed and
validated. Application of the technique to gels
currently being developed in our laboratories indicate
that the gels were apyrogenic.
vitro bacterial endotoxin test; liquid crystalline gels;
test validation; monoolein–water.