Phenyltropanes (PTs) are a family of chemical compounds originally derived from structural modification of cocaine. The main feature differentiating phenyltropanes from cocaine is that they lack the ester functionality at the 3-position terminating in the benzene; and thusly the phenyl is attached direct to the tropane skeleton with no further spacer (therefore the name "phenyl"-tropane) that the cocaine benzoyloxy provided. The original purpose of which was to extirpate the cardiotoxicity inherent in the local anesthetic "numbing" capability of cocaine (since the methylated benzoate ester is essential to cocaine's blockage of sodium channels which cause topical anesthesia) while retaining stimulant function. These compounds present many different avenues of research into therapeutic applications, particularly in addiction treatment. Uses vary depending on their construction and structure-activity relationship ranging from the treating of cocaine dependency to understanding the dopamine reward system in the human brain to treating Alzheimer's & Parkinson's diseases. (Since 2008 there have been continual additions to the list and enumerations of the plethora of types of chemicals that fall into the category of this substance profile.) Certain phenyltropanes can even be used as a smoking cessation aid (c.f. RTI-29). Many of the compounds were first elucidated in published material by the Research Triangle Institute and are thus named with "RTI" serial-numbers (in this case the long form is either RTI-COC-n, for 'cocaine' "analog", or specifically RTI-4229-n of the subsequent numbers given below in this article) Similarly, a number of others are named for Sterling-Winthrop pharmaceuticals ("WIN" serial-numbers) and Wake Forest University ("WF" serial-numbers). The following includes many of the phenyltropane class of drugs that have been made and studied.