Hi,

The FDA allows an error range for active ingredients in most generic medications. This is because it is almost impossible and unreasonably costly to blend pills so they have the exact amount of a substance in each unit.

The allowed range of error is between .8 and 1.3 of an active ingredient. Or 80 to 130%

So for example, a generic Norco 10/325 could have between 8mg and 13mg of hydrocodone in each unit. This explains why different brands/batches seem stronger/weaker than another (in addition to other variables like binders and heat exposure.)

I would imagine some companies to save money lean towards the lower part of the range, while quality companies the higher range to make their medication seem more effective.

-d