SQL & PL/SQL :: Oracle Error For Invalid Identifier In Execute Immediate Statement

I have a procedure as below. To sum up the procedure in one line it dynamically forms a string to get the values of the type which is passed as an input to the procedure.

I call the procedure as

exec exec_imm( exec_imm_t(1,'asd','1/2-34'));

ERROR:
Error starting at line 9 in command:
exec exec_imm( exec_imm_t(1,'asd','1/2-34'))
Error report:
ORA-00904: "P_TYPE_DATA"."ADDRESS": invalid identifier
ORA-06512: at "PTK_ADM.EXEC_IMM", line 26
ORA-06512: at line 1
00904. 00000 - "%s: invalid identifier"

NOTE:
When I try to execute the procedure with the execute immediate statement I get the above error. But when I execute the select statement which is nothing but the value in v_type_data directly (as seen in the comments in the code below) there is no error. But when the same v_type_data is used in execute immediate, I get an error.

CREATE OR REPLACE procedure exec_imm(p_type_data exec_imm_t)
AS
v_type_str CLOB := NULL;
v_type_data CLOB := NULL;
v_type_name VARCHAR2(25) := NULL;
BEGIN
[code]......