Regex help

[sidsel]

How is it possible to split a string containing whole words + misc numbers/letters and only return the whole words.

Ie. "Test description model A280, 28 & 6GH88"

Result:

1. Test
2. description
3. model

The metacharacter "\b" seems not to work for me.

[NogDog]

preg_match_all('/\b[a-z]+(\'[a-z]+)?\b/iU', $text, $matches);