Classification of ointment bases

1. Oleaginous bases :- It is consists of oil and fat. It is anhydrous non- washable and do not absorb water.
• Petroleum (soft paraffin) :- Semi solid hydrocarbon + lubricating oil
I. Yellow soft paraffin :- obtained from petroleum also may contain anti oxidant like vit.E and BHT. Melting range :- 38 to 56°c
II. White soft paraffin :- obtained from petroleum. Melting range:- 38 to 56°c

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