The standard is complex, basically a tablet is supposed to dissolve in up to an hour and a half. The trouble is the tablet does not sit there in the stomach endlessly. It gets dumped into the intestines. Each nutrient is absorbed in a particular part of the intestine. If the nutrient isn't released by the time it passes that precise spot, you're out of luck.
Some people think a vitamin is a vitamin.
A common coating is a shellac made from boiled insect bodies. They were chosen for their effectiveness at holding things together, instead of binders and coatings that let things come apart. You are probably aware of calcium being essential for the bones. The most commonly used is calcium carbonate. This can cause stomach gas, indigestion and be difficult to absorb.