Pharmacokinetics of subconjunctival injection of moxifloxacin in humans

Injection volume and intracameral moxifloxacin dose

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, USA.

DESIGN

Experimental study.

METHODS

Moxifloxacin 0.5%/0.05 mL, moxifloxacin 0.5%/0.10 mL, and moxifloxacin 0.15%/0.50 mL were drawn into 5 1.0 mL syringes each, injected into tared vials, and weighed. The doses delivered were calculated. The AC concentrations and elimination rates of the drug for two AC volumes were modeled for each dosing method.

RESULTS

The 0.05 mL injection volume resulted in the greatest range (35 μg) of delivered dose compared with larger injection volumes (≤25 μg). The mathematical model predicted that variation in dosing in each group would result in differences of 12 minutes or less for the presence of the drug in the AC. Injection of 0.5%/0.1 mL produced AC concentrations above 500 μg/mL for 1.9 to 3.0 hours and above 64 μg/mL for 5.5 to 6.5 hours, depending on the AC volume; however, flushing with a 0.15% concentration sustained AC levels for 1.9 hours and 5.5 hours, respectively, for the two AC volumes.

CONCLUSIONS

Smaller injection volumes of a higher concentration moxifloxacin resulted in less accuracy and less precision in the delivered dose (0.05 mL, P = .005; 0.10 mL, P = .03); however, the clinical significance of this might vary. Injection of 0.5%/0.1 mL and flushing with 0.15%/0.5 mL of moxifloxacin would provide similar drug AC residence times according to the model. Flushing provided more consistent AC concentrations with differing AC volumes.

Deep subconjunctival injection of gentamicin for the treatment of bacterial conjunctivitis in macaques (Macaca mulatta and Macaca fascicularis)

Infectious conjunctivitis occurs in a number of domestic and laboratory animal species and is usually treated topically with eye drops or eye ointments, which must be administered several times a day and sometimes for a prolonged period of time. In aggressive nonhuman primates or other large laboratory animal species, this may require the use of anesthesia or physical restraint before each treatment, which can be stressful to the animals and demanding for personnel. The authors describe a technique for administering deep subconjunctival injections of an antibiotic to laboratory macaques for the treatment of conjunctivitis. Three cases of recurrent conjunctivitis in macaques that responded poorly to other treatment approaches were effectively treated using this technique. This approach is recommended for the treatment of conjunctivitis in macaques and other large animal species.

Survey of Japanese ophthalmic surgeons regarding perioperative disinfection and antibiotic prophylaxis in cataract surgery

Purpose

To elucidate Japanese trends for perioperative disinfection and antibiotic selection during cataract surgeries.

Methods

Perioperative iodine use and antibiotic prophylaxis for cataract surgery were surveyed in eight regions in Japan by mail or through interviews from February 1 to March 1, 2014.

Results

We surveyed 572 surgeons, of whom 386 (67%) responded. Most of the surgeons (94%) used iodine compounds before surgery for periocular skin disinfection (povidone–iodine [PI]: 79%; polyvinyl alcohol-iodine [PAI]: 15%) or conjunctival disinfection (85%; PI: 36%; PAI: 49%). Preoperative conjunctival iodine was primarily used as an eye wash (irrigation: 95%) and less often as an eye drop (5%). It was determined that 31% of surgeons waited 30 seconds or more between periocular disinfection and conjunctival disinfection. During surgery, 14% of surgeons used iodine several times, including immediately before intraocular lens insertion, and 7% used the Shimada technique (repeated iodine irrigation). Preoperative antibiotic eye drops were used by 99% of surgeons, and antibiotics were added to the irrigation bottle by 22%. The surgeons reported use of subconjunctival antibiotic injections (23%), antibiotic ointments (79%), and intracameral antibiotics (7%: 22 moxifloxacin; 6 levofloxacin). All surgeons prescribed postoperative eye drops, with 10% initiating the drops on the day of surgery.

Conclusion

Iodine compounds are commonly used preoperatively, but few institutions use iodine compounds intraoperatively, particularly with repeated application. The selection of antibiotic administration and disinfection technique has to be at the surgeon’s discretion. However, intracameral antibiotic and intraoperative iodine compound use are techniques that should be widely recognized.