Concept and Terminology
Lepa are pastes or plasters intended for external use only and could be equated with the ‘ointments’ of the western pharmacopoeias. They should never be brought into contact with the delicate tissues as the ingredients are poisonous and irritating or corrosive. The term ‘lepa’ itself means that it is for external application only.
- The necessary drugs.
- Mortar and pestle.
- A wide mouthed vessel for heating the wax and oil.
- Spatula for mixing the drugs and wax-oil mixture. (In large scale preparation, electrically operated grinders, roller mills and mixers are used for making the powders and for mixing ointments.)
Process of Preparation
The lepa generally contain bees wax and/or some vegetable oil which give the paste like consistency. All the ingredients should be finely powdered prior to mixing with the waxy base. When realger and/or yellow orpiment are to be added to the preparation they are powdered separately and then added.
When the preparations contain mercury and sulphur they are ground together to homogeneity and then added to the other ingredients. Preparations which take into composition both wax and oil, have the oil heated first and wax melted into it and then powdered drugs added. The molten mixture of oil and wax are filtered before the drug powders are mixed with it. The powders should not be mixed with molten wax-oil mixture when it is hot. Mixing should be carried out until the drug particles are evenly distributed in the waxy base.
Storage and use
Lepa are stored in wide mouthed glass containers or in tins. All the lepa are meant for only external use and under no circumstances should be taken internally as some of them are poisonous.