Potentiometric determination of some glaucoma indicated drugs

A sensitive potentiometric ion selective electrodes method is presented for the determination of brimonidine tartrate, Dorzolamide hydrochloride and Timolol maleate in their pure forms, pharmaceutical dosage forms and biological fluids using phosphotungestic acid, phosphomolybdic acid and sodium tetraphenyl borate as ion exchangers. The studied electrodes are sufficiently simple and selective for the quantitative determination without the need for any pretreatment or preliminary extraction procedures from biological fluids. The method is less expensive and less time consuming compared to other HPLC and TLC methods, also, it is applicable in colored, turbid and viscous solutions of drugs. Therefore, it can be recommended for the routine analysis of the drug in quality control laboratories.