Solid Oral Dosage Forms 4 Flashcards
Types of excipient: tablets and capsules
Diluent/filler- to increase size of tablet or fill a capsule shell, to help form compacts or plugs
Binder- use to form granules, either dry or in solution
Disintegrant
Lubricant
Glidant
Wetting agent and stabilisers, colourants and flavours
Diluents: sugars
Good properties, water soluble
Lactose- most commonly used, available in a variety of forms- crystalline and amorphous, spray dried forms used for direct compression
Several sugars/sugar alcohols are used for their taste properties e.g. sucrose, glucose, mannitol and sorbitol
Used in chewable tablets and lozenges
Diluents: starches
Variety of plant sources, mainly for capsules, advantage low cost e.g. maize, potato, rice and local plants
Modified starches used in both tablets and capsules- pregelatinised, better flow properties, starch 1500, physically processed maize starch to improve flow
Diluents: inorganics
Calcium phosphate- dicalcium phosphate dehydrate and anhydrous, insoluble but hydrophilic, readily wetted; tribasic calcium phosphate
Calcium carbonate
Both used as a calcium source in nutraceuticals
Diluents: organics
Cellulose
Microcrystalline cellulose
Powdered (microfine) cellulose
Both have good compaction properties, large change in volume with compression force
Binders
Adhesive materials that hold the granules together
Wet binders- typically aqueous preparation, sometimes added to dry mix and then wetted during granulation
Dry binders- material with good compaction properties added to formulation to improve the compact strength, celluloses
Wet binders
Povidone Cellulose derivatives Gelatin Maltitol, maltodextrin Starch paste Polyethylene glycol Water principal solvent, if cannot be used then replaced with ethanol or isopropanol
Dry binders
Materials that deform plastically and fill voids in tablet mass e.g. microcrystalline cellulose
Disintegrants
Break tablets apart and disrupt powder plug in capsules
Standard Disintegrants: starch, maize, potato, do not work in hard capsules
Super Disintegrants: sodium starch glycolate, crospovidone, croscarmellose sodium
Lubricants
Stop materials adhering to moving metal parts on tabletting and capsule filling machines
Magnesium stearate- most used excipient in SODF
Sodium stearyl fumarate
Stearic acid
Polyethylene glycol
How do tablet lubricants work?
Boundary lubricants- form films at surface of die wall and tablet e.g. magnesium stearate
Stearic acid- melts to form a boundary layer
Anti-adherents
Problem with sticking on faces of tablet punches particularly with embossed punches- fault called picking
Magnesium stearate has a secondary role in preventing sticking
Talc and starches are also used
Glidants
Powders that coat other particles and reduce inter-particulate forces improving flow of the mass
Colloidal silicon dioxide
Talc
Glidants and lubricants
Both act on the surface of particles
If not properly dispersed, do not function
A minimum optimum concentration gives maximum effect and if exceeded adverse effects occur
Concentration to use related to size of surface to be covered
Wetting agents
Added to improve wetting of hydrophobic actives
Sodium lauryl sulphate
Polysorbate 80