1) To investigation a first-order process, simulating plasma elimination during and after an oral administration.
BACKGROUND:
By an arrangement of beakers and a constant head water reservoir, it is possible to simulate plasma concentrations after oral administration. The constant flow of water through the system, causes a first order dilution of the marker, potassium permanganate. You will sample the marker concentrations periodically and analyze the data using the pharmacokinetic methods appropriate to measure the parameters of the system.
Identify the plasma component to the apparatus. Make sure that the water reservoir is full. Turn on the stirrer in the plasma beaker and adjust for gentle mixing. Establish a flow rate of 20 ml/min. A value of 15 to 25 ml/min is OK.
You will be collecting plasma samples at 0, 5, 10, 15, 20, 25, 30, and 60 minutes after giving the oral dose. Arrange and label test- tubes to accommodate the samples.
The oral dose (15 drops - 250 mg) will be put in into the first beaker (g-i tract) as a single bolus as time zero.
Plasma samples. Collect the 5 ml sample at the times designated quickly by pipette.
Each sample will be analyzed spectrophotometrically at 540 nm. The absorbance of a 1 mg/ml solution has been previously determined. Early samples may need to be diluted to give absorbance readings below 1. Remember to apply this dilution factor in your analysis of the results.
Calibration of the Turner 330 model spectrophotometer
WRITE-UP:
Describe the apparatus, the working differential, and working integrated equation
Data analysis
Plot Cp versus time on semi- log graph paper. Calculate kel, ka, and V/F.
| Time (min) | Dilution Factor | Absorbance | Concentration |
| 0 | |||
| 5 | |||
| 10 | |||
| 15 | |||
| 20 | |||
| 25 | |||
| 30 | |||
| 45 | |||
| 60 |
Copyright 2001 David W.A. Bourne