Ubuntu – Unable to locate package php7.2-gd

I'm trying to install php7.2-gd on my production server.

I have 2 servers — one for dev and one for prod. When I run this installation in our dev server, everything is fine. When I tried doing this in our prod server, I'm getting the following error:

$ apt-cache search php-gd
php-gd - GD module for PHP [default]
php7.1-gd - GD module for PHP
$ apt-get install php7.2-gd
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package php7.2-gd
E: Couldn't find any package by glob 'php7.2-gd'
E: Couldn't find any package by regex 'php7.2-gd'

Additionally, I tried the following commands:

add-apt-repository ppa:ondrej/php
apt update && apt upgrade
apt-get install php7.2-gd

Still getting the error after the steps above. The php version in dev is just the same in prod. Even our ubuntu versions are the same in both servers. So I'm not really sure what else I need to do in order to install php7.2-gd in prod.

Is there a way to know why it's not picking up the php7.2-gd extension?

Version:
Ubuntu 17.10 (GNU/Linux 4.13.0-36-generic x86_64)

Update:

I tried installing php-gd as suggested but it is not working as expected because the gd.so file and the gd.ini are not in the normal directories where the other extensions are saved.

My .so extensions are normally installed in /usr/lib/php/20170718
But exploring the other folders, the gd.so was saved in /usr/lib/php/20160303

What do I need to do to correct this problem? the extension is not being recognized after apache restart.