Objective: To observe eye irritation

and therapeutic effect of Shuangqin ophthalmic gel on experimental rabbit herpes simplex keratitis (HSK)

as well as evaluate the ocular residence time of Shuangqin ophthalmic gel. Method: The experimental HSK was induced by inoculation of HSV-1 (SM44 strain) on the scratched cornea. Figty rabbits with HSK were divided into 5 groups:10% Shuangqin group

20% Shuangqin group

30% Shuangqin group

acyclovir eye drop group

and gel substrate group. Acyclovir eye drop group was treated 5 times a day

while the other groups were treated 4 times a day. The severity of corneal epithelial lesion and stromal lesion were graded and the mortality rates of the different groups were recorded. Eye irritation of the Shuangqin ophthalmic gel with the best therapeutic effect was evaluated by irritation experiment

and the retention time of Shuangqin ophthalmic gel was measured by fluorescence tracer method. Result: On the 7th day after treatment

ACV eye drop and Shuangqin ophthalmic gel had a better therapeutic effect on both epithelial HSK and stromal HSK than other groups

the severity scores in the five groups were significantly different (P<0.05). There was no significant difference between 30% Shuangqin ophthalmic gel group and ACV group. On the 14th day after treatment

the mortality rate was lowest in the Shuangqin ophthalmic gel group

but there was no significant difference among the groups. The result of irritation test showed 30% Shuangqin ophthalmic gel both had no eye irritation after treatment for one hour and 7 days. The irritation scores in the Shuangqin ophthalmic gel group

ACV group and physiological saline group were not significantly different. The residence time of Shuangqin ophthalmic gel was (133±22.5) min and (54.13±8.48)min in the conjunctival sac and cornea respectively

there was significant difference compared with ACV group and physiological saline group(P<0.05). Conclusion: 30% Shaungqin ophthalmic gel has a good therapeutic effect on experimental HSK

a prolonged residence time and no eye irritation

therefore it is a very good new drug candidate for HSK.