Abstract
Purpose :
A subcutaneous implantable port (SIP) is convenient for a patient requiring long-term treatment. To deliver effective doses of drug into the anterior chamber (AC) and maintain the drug level, we have developed a novel drug delivery system that the drug is injected into the AC through a tube from the SIP in the outside of the external canthus.
Methods :
A tip of 22G needle was stabbed the rabbit (Japanese White) limbus and moved ahead into the AC. A plunger was pressed, and the tube was inserted to the AC. The eye was incised the skin of external canthus, and the tip of tube on the conjunctiva side was exposed 5mm from the outside of external canthus. After that, the tube was connected with 32G needle of a SIP. All but the edge of the needle base were buried and the base was capped with a rubber. Then the rubber was pierced by 24G needle with 1cc syringe and dexamethasone (DEX) (10μg/ 10μl) was injected into the AC through the tube (4 eyes). As controls, rabbit eyes were received DEX by an intravenous injection (4 eyes) and topical eye drop (4 eyes). All eyes were aspirated aqueous humor at 1 hour after the treatment. DEX was extracted from the aqueous humor and DEX level was determined by liquid chromatography/ mass spectrometry/ mass spectrometry. Treated eyes were examined by slit lamp examination and ophthalmoscopy at days 7 and 14. These eyes were also assessed by histopathology on days 14.
Results :
The DEX concentrations in topical eye drop and intravenous injection groups were below the detection limit. The DEX concentration in AC tube group at 1 hour showed 2.24±2.77 ng/ml. The level of the DEX in AC tube group at 1 hour significantly higher than that of other groups (1hour; p=0.014<0.05). The AC tube eyes were shown no significant infection during the observation period. In histology, there was no abnormality in the cornea, sclera, and iris.
Conclusions :
A SIP might be useful that a patient injects a drug into the AC repeatedly through a tube from the outside of external canthus, and this SIP is effective to deliver the minimum doses of drug into the AC and maintain the drug level.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.