Extract the datatype from the SP script??

Question

am getting the stored procedure script into a string variable, like below

 

   

CREATE PROCEDURE dbo.MCpGetCLINDListview_266400(

@MCIDENTIFYINGTYPE AS VARCHAR(20),@MCIDENTIFYINGOID AS BIGINT,@RULESEARCHCRITERIA AS BIGINT)

AS

 

   but  from the string I have to hold only BIGINT word into another variable....so can any one help me how to do this??

 

please check the  attachment for clear idea