Improving the ocular to systemic ratio of topical timolol by varying the dosing time.

摘要: This study was performed to determine whether the ratio of ocular systemic absorption topically applied timolol in pigmented rabbit can be maximized by varying time drop instillation. Twenty-five microliters 0.65% maleate solutions were instilled into eye at 6 AM, 12 PM, or AM. The course concentration plasma and various tissues (conjunctiva, sclera, corneal epithelium, stroma, aqueous humor, iris-ciliary body, lens) monitored with use reversed phase high-performance liquid chromatography (HPLC). Ocular concentrations approximately twice as high when drug administered PM than whereas lowest PM. It may, therefore, possible maximize therapeutic index administering Moreover, influence dosing on extent must considered planning schedules for ophthalmic drugs. Invest Ophthalmol Vis Sci 32:27902798,1991 Absorption drugs via conjunctival nasal mucosae blood stream elicit side effects has been recognized a possibility therapy more 25 years.' Examples these include anticholinesterase agents, 2 epinephrine, 3 " 5 phenylephrine, 4 steroids. Depending physiochemical properties drug, extents occur. These range from 3% inulin 7 80% timolol. 8 Nevertheless, not attempts optimize until beta-blockers widely used patients glaucoma. 9 Several approaches have investigated relative reducing absorption, results positive. nasolacrimal occlusion without eyelid closure, 1011 microdrops, vehicles extended residence sac, 1213 coadministration vasocontrictors such phenylephrine 14 soft that are