The answer is Negative charges on phosphate groups repel each other. The oxygen groups of a phosphoanhydride in ATP have electron cloud that repels each other. On hydrolysis, once a phosphate is lost, the electrostatic repulsion is reduced.
When ATP is hydrolyzed, it forms more hydrogen bonds with surrounding water molecules that when ATP is unhydrolyzed. Therefore, more energy is released since more bonds are formed than are broken. The net delta G is positive during hydrolysis of ATP.
The pen would contain Insulin as people with diabetic problems do not have enough insulin in their body to help them break down the sugar