Description Application 1,1,1-Trichloro-2-methyl-2-propanol hemihydrate (chlorobutanol) is a preservative used as a standard for quantifying preservatives in pharmaceutical formulations by using capillary electrophoretic method. It has also been used to anesthetize leeches for preparing c-DNA library from regenerating retzius cells. Biochem/physiol Actions Chlorobutanol or 1,1,1-Trichloro-2-methyl-2-propanol is a opthalmic preservative and sedative hypnotic that possess antibacterial and antifungal properties. It also decreases the conduction velocity and induces conduction failure and automaticity within isolated ventricular muscle strips as well as impacts myocardial cells by acting on cell membrane and reduces isometric tension produced by heart.