Excipients Use In Dry, Wet Granulation And Direct Compression In Tablet Manufacture

Excipients are additive substances used in tablet formulation to improve bulkiness, disintegration, dissolution rate and bioavailability of the drug. There are different methods of tablet manufacture. These methods need different types of excipients.

tablet

Excipients Use In Direct Compression

Direct compression formulations can be developed with minimal numbers of excipients. Typically the minimum excipients needed are a diluent (filler binder), a disintegrant and a lubricant. Additional components may include a glidant, a surfactant, pigments and stabilising agents. Of course some excipients are described as multifunctional.

Read Also: Manufacture of tablet process

Stabilisers: These are typically used, if necessary, to minimise pH dependent hydrolysis or oxidation depending on the requirement of the drug substance. To promote intimate contact of the drug with the stabiliser it is generally recommended to include the stabiliser in finely divided form at the premix stage. 

Colourants: To obtain evenness of colouration in DC formulations the use of insoluble pigments (aluminium lakes and iron oxides) is preferred. Inclusion at the premix stage can minimise “speckling” in the finished tablets. Alternatively the tablets can of course be film coated. 

Surfactants: Wetting agents such as sodium lauryl sulphate may be included, especially if the drug the substance is hydrophobic.

Excipients Use In Dry Granulation

Diluent/filler, e.g., Microcrystalline cellulose (MCC), anhydrous lactose or lactose monohydrate, dibasic calcium phosphate, starch etc.

Disintegrants, e.g., croscarmellose sodium, sodium starch glycolate, pregelatinized starch 1500, crospovidone, starch, MCC, etc.

Lubricants, e.g., stearates (magnesium stearate, stearic acid), glyceryl fatty acid esters (glyceryl behenate, glyceryl palmitostearate), Polyethylene glycol (PEG), polyoxyethylene stearates, sodium lauryl sulphate.

Glidants, e.g. talc, colloidal silicon dioxide.

Miscellaneous excipients such as colourants, flavourant, sweetening agents, etc.

Read Also: List of excipients use in manufacture of drugs

Excipients Use In Wet Granulation

Key process stages include blending the dry powder mix, wet granulation with water or another binder solution, adding any additional components, further lubrication and final compaction.

Excipients used in Wet granulation typically include diluent, binder, disintegrant and lubricant, while other stabilising agents and pigments may also be included.