• We have obtained comparative data for the intraocular absorption of topically administered clindamycin hydrochloride hydrate and clindamycin phosphate, made feasible with a new gas chromatographic method of analysis. Results indicated that clindamycin phosphate underwent hydrolysis in the eye, liberating the biologically active clindamycin. However, topical clindamycin hydrochloride produced higher levels (two to six times more) of the antibiotic than those achievable with the phosphate ester in the uvea, aqueous humor, and cornea, presumably due to clindamycin hydrochloride's higher lipid solubility. Based on this data, clindamycin hydrochloride appears to be the preferred form of the antibiotic for topical ocular applications.
Devlin JL, Mercer KB, Dea FJ, Leopold IH. Intraocular Penetration of Topical Clindamycin in RabbitsII. Clindamycin Phosphate. Arch Ophthalmol. 1978;96(9):1650-1652. doi:10.1001/archopht.1978.03910060276019