Faculty of
Pharmacy
Department
of Pharmaceutical Technology
Pharmacy
Practice Lab III
Objectives:
1. To prepare tablets by direct compression a powder formulation.
2. To practice using reliable sources of information to find out products from the identification markings on the tablets.
3. To practice using JFDA
website (In-lab assignment)
Introduction:
Tablets are the common dosage form available in the market due to its desirable advantages which include the following:
n Patient acceptability:
n Noninvasive
n Portability
n Hard to tamper with tablets
n Easy to swallow, especially if coated.
n Relatively easy to manufacture and package
n Provide accurate dosing
n Increased stability of the drug when compared to liquid dosage forms.
n Product identification is easy especially with use of imprints.
n Can be enteric coated or designed for delayed release.
However tablets have few disadvantages which include the following:
n Formulation difficulties, if drug resist compression.
n Some drugs have poor wetting or poor water solubility or poor dissolution which might affect the drug’s bioavailability.
n Bitter taste of the drug might require coating.
Tablet manufacturing:
n There are 3 main methods of producing tablets:
n Direct compression
n The drug itself is compressible and/or it can be mixed with a filler that is compressible (e.g. lactose).
n Wet granulation
n The powder mixture of the drug and excipients is granulated by wet methods prior to compression.
n Dry granulation
n The powder mixture of the drug and excipients is granulated by dry methods prior to compression.
n In all of these methods the active ingredient is usually mixed with other inactive ingredients (excipients).
n Excipients improve the physical properties of the tablet.
n Excipients are components of tablets that that have a role other than the therapeutic effect, they include:
n Fillers (diluents)
n Binders
n Disintegrants
n Lubricants, and glidants
n Preservatives
n Flavoring agents
n Film formers
n Opacifiers and colors
Identification markings:
In addition to color, size, and shape products can be identified from their tablets using a unique marking. These markings can be embossed engraved or printed on the tablet surface. The following websites can be used to identify a product from the markings on the tablet:
- Lexi-comp online:
- Drugs.com
- Rxlist.com
Tablet preparation by direct methods:
Tablet ingredients are weighed according to formulation need, blended then compressed. This process is suitable for moisture and heat sensitive drugs.
Direct compression of aspirin tablets:
Ingredients quantity per tablet (mg) quantity for 100 tab (gm)
Aspirin 425 42.5
Aerosil 14 1.4
Dry starch 56 5.6
Magnesium stearate 2.5 0.25
Talc 7.5 0.75
Method:
1. Screen each powder ingredient in the mixture to remove any lumps or aggregates.
2. Weigh the proper amount of each ingredient to prepare a total of 100 tablets.
3- Blend the pre-weighed powder to make a homogenous powder mixture.
4- Compress the powder mixture using the single punch press machine available in the lab.
Practical: