Binding Studies of Lamotrigine with Sera of Different
Animal Species
Kalyan Kumar Sen1*,
Sanat Kumar Basu2 and Sadhan Kumar Dutta1
Pharmacy Divisions, Gupta College of Technological
Sciences, Ashram More, G.T. Road, Asansol-713301,
2Department of Pharmaceutical Technology,
Jadavpur University, Kolkata-700032, India.
*Corresponding author:
E-mail:
kkskpa@gmail.com
Mobile: +91-9932334958
Received: 25 October
2008
Revised accepted: 17 July 2009
Tropical
Journal of Pharmaceutical Research, October 2009; 8(5):
409-415
Abstract
Purpose: The
serum protein-binding characteristic of lamotrigine with
sera from various species (horse, rat, rabbit and goat)
was studied at different dielectric constants and
temperatures to obtain an insight into the mechanism of
interaction, evaluate the effect of dielectric constant
on binding affinity, and to determine the effect of
species variation on drug plasma-protein interaction.
Method: Binding
data were generated by evaluating equilibrium dialysis
of lamotrigine in methanol-water solvent (1:1 and 1:3)
with horse serum at 20, 28 and 37 0C The
equilibrium dialysis evaluation of lamotrigine with sera
of other animal species - rabbit, goat and rat - was
also performed at 37 0C.
Results:
A Rosenthal plot obtained with the binding data at
different temperatures showed that binding constant
decreased with increasing temperature and that binding
of lamotrigine to horse serum appeared to be saturation
binding. The results also indicated that the binding
process was characterized by negative
DH0
value and a small positive
DS0
values. The binding constant decreased as dielectric
constant rose.
Conclusions:
The results obtained suggest that hydrophobic
interaction may have occurred and that van der Waals’
forces were responsible for binding in the hydrophobic
region. Data obtained for lamotrigine binding with
horse, goat, rabbit and rat sera show that there are no
significant changes in plasma protein binding in the
above-mentioned species.
Keywords:
Lamotrigine; Serum protein binding; Dielectric constant;
Binding constant; Animal sera
