The Big Bust Out (1972)

Starring:

• Vonetta McGee
• Monica Teuber
• Linda Fox

IMDB.com
"Inside a high security prison, seven beautiful women become allies against their sadistic cell-block matrons and stage THE BIG BUST OUT - a massive, violent escape.  They make their way to the home of an ex-boyfriend who reveals his true sympathies by selling them into white slavery.  In a furious gun battle the women escape from the slaver, but it is only the beginning of a long and desperate journey to freedom."