Abstract:
Hemoglobin is responsible for transporting oxygen throughout the body. Because of the
enormous molecular weight and the structure of hemoglobin, there could be a possibility
that a certain drug will not be reversibly released from the Hemoglobin molecule once
bound. Because of its size, such a Hemoglobin bound drug will form a complex that will
be unable to diffuse through blood arteries. As a result, the free concentration of the
drug may be affected. The goal of this study is to determine the Amoxicillin binding
capacity to Hemoglobin and to predict the free dug availability for pharmacological
action. Equal volumes of amoxicillin (0.8 mg/mL) and Hemoglobin (4 mg/mL) in pH
7.4 buffer were mixed and incubated at 37 ◦C for 1,2,3 and 6 hours. A 1 ml sample of the
incubated reaction mixture was dialyzed (14-12 kDa), against pH 7.4 buffer solution for
three hours. The concentration of Amoxicillin in the dialysate was measured using High-
Performance Liquid Chromatography. The concentration of amoxicillin in the dialysate
was constant from 1 to 6 hours indicating that the amount of amoxicillin bound to
the Hemoglobin was maximum at 1 hour and was a constant throughout. Since the
initial drug concentration was sufficient to saturate the Hemoglobin, the ratio of the
bound drug to the unbound drug was 1: 13. Further computations of the moles of
bound drug and initial moles of hemoglobin revealed that two Amoxicillin molecules
were bound to one Hemoglobin molecule confirming that Hemoglobin has two binding
sites for amoxicillin.
