Washington ? Missing information, loopholes and weak oversight hamper efforts to uncover financial conflicts by researchers who test experimental drugs before companies seek government approval, an internal watchdog finds.

As a result, the Food and Drug Administration’s screening system is unreliable, the Health and Human Services inspector general’s office said in a report being released today.

Because scientists can be tempted by profits, the government requires disclosure of possible conflicts involving clinical researchers who review medications before drug companies seek FDA approval. In all, 42 percent of the applications lacked complete financial information and not even 1 percent of researchers disclosed possible conflicts.