A clinical evaluation of a novel liposomal carrier for acyclovir in the topical treatment of recurrent herpes labialis

In a 2-armed, double-blind, randomized clinical study, the efficacy in the treatment of recurrent herpes labialis of 5% acyclovir in a novel liposomal carrier (ethosome) was evaluated in comparison with that of a commercial 5 % acyclovir cream (Zovirax cream) and that of a drug-free vehicle. Data wer e based on 61 herpetic episodes in 40 subjects. In a crossover arm in which the 2 active preparations were compared, the time to crusting of lesions w as significantly shorter (P <.025) with the ethosomal acyclovir (1.8 days) than with the cream (3.5 days). Time to loss of crust was also significantl y shorter (4.2 vs 5.9 days; P <.05). In a parallel arm in which all 3 prepa rations were compared, the time to crusting with the ethosomal acyclovir (1 .6 days) was significantly shorter than the time with the acyclovir cream ( 4.3 days; P <.02) and the time with the drug-free vehicle (4.8 days; P <.00 5); in this arm, the shorter time to loss of crust for the ethosome (3.5 da ys), in comparison with the times for the cream (6.4 days) and the drug-fre e vehicle (6.7 days), did not reach statistical significance. Approximately 30% of all episodes treated with the ethosome were clinically abortive; th is compared with 10% of those treated with the cream or the drug-free vehic le. No adverse effects were reported, other than minor burning sensations a t the application site that lasted a few seconds after application and were evenly distributed between the investigated preparations. This pilot study suggests the improved clinical efficacy of the new liposomal preparation i n comparison with Zovirax cream in the treatment: of recurrent herpes labia lis.