The most common and most likely answer to this crossword clue is the 7 letter word AMPOULE
I've seen this crossword clue in Financial Times
A
M
P
O
U
L
E
More clues leading to the result AMPOULE
- Four internally occupying large capsule
- A smuggler hides cut drug in small glass vessel
- Ought uranium be kept in large sealed container?
- A beast carrying pot and little bottle
- A person assisting dealer keeps postal order for small container
- Vessel from which a pack animal is injected with polonium
- Uncovered roux in large enough container
- Small glass vessel sufficient to contain old uranium
- Small bottle found in a drug smuggler containing cannabis, mostly
Buddy explains!

The straight part
We know that "little bottle" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case little bottle = ampoule.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does AMPOULE mean?
AMPOULE noun- A small hermetically sealed vial, often used to contain a sterile solution suitable for injection.