Posters

Injection volume and intracameral moxifloxacin dose

Poster Details

First Author: N.Shorstein USA

Co Author(s):    S. Gardner                    

Abstract Details

Purpose:

To test the effect of injection volume and concentration on dosing and residence time of moxifloxacin in the anterior chamber (AC).

Setting:

Kaiser Permanente, Walnut Creek, California

Methods:

Moxifloxacin 0.5%/0.05 ml, 0.5%/0.10 ml and 0.15%/0.50 ml were injected into tared vials and weighed. Doses delivered were calculated. We modelled AC concentrations and elimination rates of drug representing two different AC volumes for each dosing method.

Results:

The 0.05 ml injection volume resulted in the greatest range (35 µg) of delivered dose compared to 25 µg or fewer for the larger injection volumes. The model predicted that variation in dosing within each group would result in a difference of only 18 minutes or fewer of drug presence in the AC. Injection of 0.5%/0.1 ml produced AC concentrations above 500 µg/ml for 2 to 2.9 hours and above 64 µg/ml for 5.5 to 6.5 hours, depending on AC volume. Flushing with a 0.15% concentration would sustain AC levels for 1.9 and 5.4 hours, respectively, for both AC volumes.

Conclusions:

Smaller injection volumes of higher concentration moxifloxacin resulted in less accuracy and less precision in delivered dose; however, the clinical significance of this may vary. Injection of 0.5%/0.1 ml, and flushing with 0.15%/0.5 ml moxifloxacin, would provide similar drug AC residence times according to the model. Flushing offered the advantage of more consistent AC concentrations with differing AC volumes. Further studies examining the effect of injected volume, dose and AC concentration in vivo are warranted.

Financial Disclosure:

None