No more than 4 players under 23 and 4 players over 23 can be on standard loan during a season. Standard loan is half season or full season. Doesn't seem to apply to month long loans.
No more than 5 loan loan players can be on a team sheet for the match.
If you want some bedtime reading here you go
http://www.football-league.co.uk/reg...633_2125731#50