Forms :: Dynamically Passing The Columns Values?

I am trying a pl/sql block which which take a string and execute it dynamically. Suppose below is string

M_COL := Q'[(P_CODE=> ':DEPTNO',P_CODE_TYPE => 'STATE')]';

Now trying to execute it. using below

M_STR := 'SELECT CHK_DEPT' || M_COL || ' FROM EMP WHERE EMPNO=''7499''';
EXECUTE IMMEDIATE M_STR
INTO M_DATE;

Now what i want is M_STR vairable to executed as

SELECT CHK_DEPT(P_CODE=> DEPTNO,P_CODE_TYPE => 'STATE') FROM EMP WHERE EMPNO='7499'

instead of

SELECT CHK_DEPT(P_CODE=> 'DEPTNO',P_CODE_TYPE => 'STATE') FROM EMP WHERE EMPNO='7499'

other in other way in parameter P_CODE Column value of DEPTNO should be passed.Also note that DEPTNO column in string M_COL is Dynamic.i.e

M_COL := Q'[(P_CODE=> ':DEPTID',P_CODE_TYPE => 'STATE')]'; OR
M_COL := Q'[(P_CODE=> ':EMP_ID',P_CODE_TYPE => 'STATE')]';