Regex: Find the letter (diacritics) î in the middle of the words, but not the letter î at the beginning or at the end of the words

I must find the letter (diacritics) î in the middle of the words, but not the letter î at the beginning or at the end of the words.

For example:

1.stăpînii

2.înstăpanit

3.coborî

4.înfornît

So the regex must find the letter î just from words like the first one: stăpînii.

The 2 and 3 word have the letter î at the beginnind or at the end. So those must be ignore from finding.

The 4 case is tricky. It starts with î and also has an î in the middle. So, only the second î must be find by regex.

FINAL: Regex must find the letter îfrom the first word stăpînii and also must find the second î from the last word înfornît