Mean BPG level and 95% confidence interval versus day since injection.

<p>Each subject provided a sample 1 day after injection and two more over the course of 28 days. The serum penicillin G half life is 4.1 days. At approximately day 11 the expected mean penicillin G serum level is less than 0.02 µg/ml. On days 1, 2 and 3 the 95% confidence intervals extend upward beyond 0.13 and are truncated to allow more visual resolution at the lower end of the curve. (Note: day 21 outlier removed from calculation of mean; see text.).