在PHP应用程序中使用IAM连接到RDS数据库

I have developed an application using the PHP SDK for AWS. It is hosted on AWS also.

I have written a connections file, detailing all the variables and credentials required to connect to the DB, and this works fine.

However, in terms of security I was wondering if it is possible to use an IAM Role, as that is what I am using to connect to the EC2 instance, so that I am not explicitly defining the credentials?