Creating DB link inside stored procedure

I am trying to create DB link from stored procedure. I create a procedure like the following.. but when i executed the query i got error "ORA-01031: insufficient privileges". When i ran the following query,it was working.

create database link TESTING3 connect to user1 identified by "pwd" using 'user1.system.COM'

But when i kept it inside Stored procedure,it was not working. It may be related with single quotes,but i couldn't fix it. Any help on this would be appreciated.

CREATE OR REPLACE PROCEDURE PROC1 IS
BEGIN
execute immediate 'create public database link TESTING5 connect to user1 identified by "pwd" using' ||''''|| 'user1.system.COM'||'''';

   EXCEPTION

     WHEN NO_DATA_FOUND THEN
       NULL;
     WHEN OTHERS THEN
       -- Consider logging the error and then re-raise
       RAISE;