Lots of packaging advice already given but it is important that the bottle cannot be hit by another solid object in the case. So pack all separately. I carried some mugs in checked in baggage and the only one that broke was the one with a small plastic hotel bottle of shampoo inside which was able to move about.

(Years ago I did some experiments with students on eggs. A hen's egg will stand a mass of 2kg or more on its long axis when placed there carefully. However, a single gram weight falling from 1 metre will smash a small hole. Gentle crushing it resists well, sudden very small shock fractures it.)