Excipients

WHAT IS A LUBRICANT?

1] A lubricant is an excipient which is added to a powder blend to prevent the compacted powder mass from sticking to the equipment during the tabletting or encapsulation process. It also aids the ejection of the tablet from the dies, and in some cases may help improve powder flow.

A lubricant should be added to a powder blend for direct compression or encapsulation. It is generally added dry, and in the final blending stages.

Hydrogenated Vegetable Oil, Type 1	Typically require higher concentrations for lubricity than the stearates. Doesn't have the overblending problems seen with magnesium stearate.

Magnesium Stearate	A common and extremely effective lubricant. Works in concentrations from 0.5 - 5%. Although, it is best to use this lubricant in the lowest effective concentration. Blending times should be limited. Overblending can cause compaction problems.

Stearic Acid	Not as effective as magnesium stearate. But frequently used in combination with magnesium stearate, to get a synergistic lubricant effect on punch faces and die walls. Doesn't have the overblending problems seen with magnesium stearate.

Sodium Stearyl fumarate	Extremely effective lubricant at low concentrations. Doesn't have the over blending problems seen with magnesium stearate. However, it is also more expensive.

Vegetable based Fatty Acids	Vegetable fatty acid (90% palmitic/stearic acid), contains no metal (magnesium, zinc, or calcium) residue. Good tablet hardness, good for chewable tablets, smoother,shinier tablets than the metal stearates. Less sensitive to overblending than the metal stearates. Less reactive, can be used with acidic substances.

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Pformulate/05/05/2000