Abstract
Purpose: :
To design and test an alternative delivery system of eye drop administration that allows for efficient and reliable alteration in drug dosage to the eye by varying drop size in a predictable and precise manner from a single bottle
Methods: :
The study incorporated a commercially available Luer lock cap adapter that screws on to a conventional 15 mL low density polyethylene (LDPE) ophthalmic bottle matched to removable sterile flexible plastic tips of various inside bore diameters. The internal bore diameters of the tips studied were 0.250, 0.840 and 1.370 mm respectively. The mean drop volume for each tip size as well as the drop volume from a conventional 15 mL ophthalmic bottle tip was determined by densitometric methodology using sterile water as the test article. To determine the dose-response of the Luer lock tip system clinically, surrogate bioavailability of 0.5% tetracaine HCL applied to the corneal surface of New Zealand white rabbits was assessed with a Cochet-Bonnet anesthesiometer. Surrogate bioavailability was determined by assessment of the area under the time-filament length curve (AUC).
Results: :
Mean drop volume for the tips of 0.250, 0.840 and 1.370 mm bore size was 11.34, 18.39 and 28.15 µL respectively. Mean drop volume of the commercial tetracaine HCL bottle with a conventional tip was 36.04 µL. The coefficient of variation ranged from 3.96% for the 0.840 bore size to 6.94% for the commercial tip. A one way analysis of variance (ANOVA) demonstrated a statistically significant difference between mean drop volumes among all test groups (p <0.0001). Tetracaine AUC for the 0.250, 0.840 and 1.370 bore tips was 71.48, 88.30 and 73.14 min-cm respectively. The tetracaine AUC for the conventional tip was 81.04 min-cm. Use of a 0.840 mm bore tip vs. a conventional tip increased tetracaine AUC by approximately 8.0%.
Conclusions: :
Topical ophthalmic drop volume can be modifiable in a reliable and precise manner through use of a novel Luer lock tip-bottle combination system. The system can provide desired flexibility in dosing topical ophthalmic medication simply through changes in the bore of the delivery tip. Use of variable size ophthalmic tips may provide significant cost savings while preserving therapeutic effectiveness. Further study will examine the safety and efficacy of such a system applied to a range of pharmaceutical entities through dose-response assessment.
Keywords: cornea: clinical science • drug toxicity/drug effects • pump/barrier function