The mexican ninja (1991)

A criminal organization hires some ninjas to steal the formula for a new drug, described as cheaper and more powerful than cocaine. As it turns out, the industrialist who financed the research has taken elaborate steps to make sure that the new substance won´t fall into the wrong hands, and the ninjas find they have only succeeded in stealing half the formula. To please their disgruntled employers, the evil ninjas try to blackmail the industrialist into handing over the remaining half and it's up to the Mexican Ninja and his pals to stop him.