In evaluating any chemotherapeutic agent against infection in vivo, one has to determine the best method of administration for the anatomic site involved. In treatment of corneal infections with penicillin two main routes of administration are available, local application to the cornea and systemic administration.
Two methods of obtaining information concerning the routes of administration in experimental animals allow one to predict the results to be expected in human beings. Both methods are essential. The first is to determine the concentration reached in the cornea by the various means of administration ; the second is to compare the effects of the methods against a standard lesion. No one has measured the concentration of penicillin in the cornea produced by either local or systemic use. The present biologic methods of estimating the concentration of the drug make such a determination in corneal tissue most difficult. It was our purpose in this study
LEOPOLD IH, HOLMES LF, LaMOTTE WO. LOCAL VERSUS SYSTEMIC PENICILLIN THERAPY OF RABBIT CORNEAL ULCER PRODUCED BY GRAM-NEGATIVE ROD. Arch Ophthalmol. 1944;32(3):193–195. doi:10.1001/archopht.1944.00890090043005