The present invention relates to a liquid pharmaceutical composition containing an N-phenylpyrazole derivative as active ingredient and alpha–omega-hydroxypoly as solvent for the treatment andor prevention of infestations with fleas in domestic animals. The at least one LED can be thermally connected to the thermally conductive substrate through the post and electrically connected to the patterned conductive layer. The method further includes providing a substrate, forming a coated substrate by coating a surface of the substrate with a layer of the solution, and providing a photo mask having a predetermined pattern thereon transparent to a predetermined radiation over the coated substrate.