Purpose: To investigate the interaction between quinine and
Garcinia kola
using an
in vitro adsorption
study.
Methods: In vitro interaction between quinine and
G. kola was conducted at 37 ± 0.1 °C. Adsorption of
quinine (2.5 - 40 μg/ml) to 2.5 % w/v
G. kola suspension was studied. Thereafter, quinine desorption
process was investigated. The amount of quinine adsorbed and desorbed was quantified using HPLC. A
Freundlich isotherm was constructed to describe the resulting data and percentage of quinine desorbed
was determined from the desorption data.
Results: An adsorption isotherm of the data gave a Freundlich constant (K) of 52.66 μg/g, with a slope
of 0.69 indicating a high capacity and affinity of
G. kola to adsorb quinine at a concentration smaller
than 2.41 μg/g of
G. kola. However the adsorptive capacity of
G. kola for quinine at 37 ± 0.1 °C appears
to be a saturable process as observed from the isotherm. Quinine desorption from
G. kola peaked at 1
hour (37.51 %) and decreased to a constant amount (about 35 %) over the remaining sampling time.
Conclusion: Quinine is adsorbed on
G. kola in vitro. This suggests that concurrent administration of
quinine and
G. kola should be avoided, to prevent potential drug interaction and decreased drug
bioavailability.
