A mixture of distyrene (a polystyrene), a plasticiser (tricresyl phosphate), and xylene, called DPX, was introduced in 1939 and later modified by the substitution of a more satisfactory plasticiser, dibutylphthalate (butyl, phthalate, styrene - BPS).
This colourless, synthetic resin mounting media is now available at ProSciTech and has generally replaced xylene-balsam.
It preserves stains and dries quickly. Surplus mountant may be peeled off the preparation after cutting around the coverslip with a razor blade or a scalpel. It is not recommended for use with thick sections (e.g. cellulose nitrate) where there is a danger of retraction of the mountant upon drying. For these Canada Balsam (IA158) is a suitable alternative.
ENTELLAN® NEW (IM022) replaces DPX (Depex).