Abstract: An agent for contact lenses, comprising chloroacetamide. According to the present invention, chloroacetamide, which is the bacteriocidal component to be contained, is scarcely adsorbed not only to hard contact lenses and gas-permeable hard contact lenses, but also to soft contact lenses, and even if adsorbed, moreover, chloroacetamide is quickly released and is not accumulated on the contact lens to a greater extent. The inventive agent containing, in addition to chloroacetamide, sodium lauryl sulfate shows more superior bacteriocidal effect and cleaning effect. Therefore, the present invention provides an agent for contact lenses having superior bacteriocidal effect and cleaning effect, which can be used safely and with ease for various contact lenses inclusive of soft contact lenses.

Abstract: Presented is a novel quinolonecarboxylic acid derivative of the formula I and its pharmaceutically acceptable salt: ##STR1## wherein R.sub.1 is hydrogen, halogen or lower alkoxy, R.sub.2 is hydrogen, lower alkyl, lower alkoxy, --NH.sub.2, --NHCOCH.sub.3 or halogen,R.sub.3 is lower alkyl, and z is a group represented by the formula II or III: ##STR2## wherein R.sub.4 and R.sub.5 are identical or different and are hydrogen or lower alkyl. A method of preparation of these compound and a method of treatment of diseases caused by bacterial infection are also presented.