1. Assume that following excipients are used in reference product:

• Lactose
• Starch
• MCC
• Mg. Stearate

2. Label claim : 30 mg active / Tab

3. Reference tablet weight found avg.: 306 mg

4. DT found: 12-14 min.

With above info, a formulator can easily find tentative quantity of the excipients.:

• Take a look at the excipients; Lactose & active (suppose) is water soluble.
• Starch, MCC & Mg. Stearate is water insoluble.

Now, take 10 tablets & dissolve into water. API & Lactose will be soluble and others will precipitate.

Now filter the suspension. After filtration, dry both solution and precipitate.

After drying  solution part, weight found 2.54 gm and  precipitate part weight found 0.50 gm.

Total weight found 3.04 gm ~ 3 gm~ 300 mg x 10 tablet = per tablet weight 300 mg

Soluble part (Lactose + API) weight found: 2.54 gm

API per tablet 0.030 gm ~ 0.3 gm for 10 tablets.

Lactose quantity in 10 tablets: 2.54 - 0.3 gm = 2.24 gm ~ 224 mg per Tab

Precipitate part (Starch + MCC + Mg. stearate) weight found 0.50 gm.

Now Mg. stearate is normally used as lubricant at 1.0% w/w. ~ 3 mg per Tablet

As the Tablet DT is high the binder (Starch) content is high. Lets say 5.0 % w/w. ~ 15 mg per Tablet

In the formula following are found :

• Active : 30 mg ~ 10%
• Diluent : Lactose ~ 224 mg ~ 74.67 % ~ 74 % ~ 222 mg
• Binder : Starch ~ 15 mg ~ 5%
• Lubricant : Mg. Stearate ~ 3 mg ~ 1 %
• Disintegrant :. ...................
• MCC acts as disintegrant at 5-15 % w/w. So 10% is ideal.
• Disintegrant: 30 mg ~10 %

So Tentative formula for Optimization :

• Active : 30 mg ~ 10%
• Diluent : Lactose ~ 222 mg ~ 74 %
• Binder : Starch ~ 15 mg ~ 5%
• Disintegrant : MCC ~ 30 mg ~ 10%
• Lubricant : Mg. Stearate ~ 3 mg ~ 1 %
• Tablet weight 300 mg