Before the content loader action create an additional TRUE action with a lower dsiplay sequence and set a hidden page item on the current page (e.g. P105_PRODUCT_ID) using the "FOEX Grid Row Select Set Item Values". Then use similar syntax in your URL:
Alternatively if you need to support session state protection then add a new column to your report called url and set it's "Display As" setting in the report attributes to hidden. You SQL query should look like:
SELECT apex_util.prepare_url('f?p='|| :APP_ID ||':106:'|| :APP_SESSION ||'::'|| :DEBUG ||'::P106_PRODUCT_ID:'||product_id) url
Then on row selection use the same "FOEX Grid Row Select Set Item Values" dynamic action to set a hidden item called e.g. P105_URL using the grid URL column alias and then use #P105_URL# as the url for the content loader.