Her days were spent in classrooms studying the complexities of medical science. After dark, she was living a secret double life as a Sydney drug dealer and sex escort.

When NSW Police stopped a vehicle in Sydney's west, it unexpectedly triggered a bust in which a stash of drugs was found at the home of 19-year-old Western Sydney University biochemistry student Madeline Christine Sawyer.

Madeline Sawyer with her lawyers after pleading guilty to drug charges. Credit:Anthony Johnson

Among the cache was 28 capsules of MDMA powder, 15 resealable bags collectively containing 11 grams of cocaine and a further 11 individual, one gram bags of methamphetamine, better known as ice.

On Monday, Ms Sawyer will be sentenced in Campbelltown Local Court, having previously pleaded guilty to six supply and possession charges and a further count of dealing with suspected proceeds of crime.