Please help! what is the difference between hydrocodone and hydrocodone bitartrate?

There isnt any: Most drugs exist as salts - a combination of the parent drug with another molecule, in this case bitartrate. This often makes the drug more absorbable from the stomach and intestines. Many drugs are hydrochloride salts or other kinds of salts. Sometimes the particular salt may alter the potency of one form over another, but not usually. Most hydrocodone is in the bitartrate form.