Abstract:
Haemoglobin is responsible for transporting oxygen throughout the body. Because of
the enormous molecular weight and the structure of haemoglobin, there could be a
possibility that the 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 drug 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.
1 ml 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 mols of haemoglobin revealed
that two Amoxicillin molecules were bound to one Hemoglobin molecule confirming
that Hemoglobin has two binding sites for amoxicillin.
