SQL & PL/SQL

Hi,
need some help

Version:Oracle Database 10g Enterprise Edition Release 10.2.0.1.0

DECLARE
	lv_dept VARCHAR2(100);
	Currec EMP%ROWTYPE;
	Cursor Cur_Dept(pv_dept VARCHAR2) IS SELECT * FROM EMP WHERE to_char(deptno) IN (pv_dept); 
BEGIN
   lv_dept:='''10'''||','||'''20''';
 	 OPEN Cur_Dept(lv_dept);
   LOOP
  	 FETCH Cur_Dept INTO Currec;
                 Message(Currec.Ename||Currec.deptno); --Forms code
	 EXIT WHEN Cur_Dept%NOTFOUND;	
   END LOOP;
   close Cur_Dept;
END;	
 

If I pass the parameter as a string , it doesn't work.

Regards,
Lokanath