Microemulsions with timolol as potential eye drops.

Stable microemulsions oil-in-water (o/w) and water-in-oil (w/o) with timolol were obtained. These formulations were sterilized using two methods: by autoclaving and by sterile filtering according to the Polish Pharmacopeia V. Microemulsions were kept in the temperatures of 25 degrees C and 5 degrees C during three months. The following physical parameters were investigated: density, dynamic viscosity, refractive index, surface tension, pH and osmotic tension. All the microemulsions met the requirements for eye drops.