Sac lac is the common name for the substance that has no remedy on it. Two major types used for remedies are granules and tablets. Lactose powder was used around the turn of the century.
Made from cane sugar not lactose.
Tablets come in two types: compressed and triturated.
The compressed involves a two step process. It is lactose that is moistened with alcohol and then "balled." The balls are then mixed with a binder (corn syrup is often used) and compressed into tablets. These are hard disks.
The triturated tablets are just lactose mixed with a binder (gum arabic) and pressed into shape. They are soft and crumbly but dissolve much faster in the mouth.