Medical tablets are made from much more that just the active compound. Other ingredients are required to give the tablet volume, colour and to make sure the manufacturing process runs smoothly.
Silicon dioxide - This is added during the manufacturing process to help the various powders that make the tablet flow nicely together.
Lactose - This is used in many tablets, including aspirin and paracetamol, to bulk them out.
Ibuprofen - The active ingredient only makes up 200mg of a standard tablet.
Sodium lauryl sulphate - A detergent that crops up in many household products, including shampoo and toothpaste. In tablets it is used as a lubricant to stop the various ingredients sticking to manufacturing equipment.
Titanium dioxide - This turns up in a lot of products, from tablets to sunscreen to paint. It is used as a white pigment.