SDFs - Tablet Coated & Effects

What are the types of tablet coating?

• Sugar

• Film

• Compression coatings

What is sugar coating?

• Oldest method

• Aqueous solutions of sucrose are deposited repeatedly on the tablets until a smooth, aesthetically pleasing coat is formed

What are some advantages of sugar coating?

• Protecting the drug from environmental factors (air, moisture, light)

• Barrier to objectional taste or odor

• Enhance product appearance

• Imprinting possible

What are some disadvantages of sugar coating?

• Up to 50% increase in tablet size, weight & shipping cost

• Time consuming process

What is film coating?

Thin polymer film onto tablet surface

What are some advantages of film coating?

• Speed: 2-4 hours

• Reduced production space

• Minimal weight increase (2-4%)

• Does not need expertise

What is used in aqueous film coating?

Water is used as a solvent, preferred for environmental reasons

What is used in nonaqueous film coating?

Not water or the polymer is not water soluble

What is an example of what is used in aqueous film coating?

Cellulose ether polymers (HPMC, HPC)

What is a plasticizer?

Produce flexibility and elasticity of the coating, providing durability

What are examples of plasticizer?

• Glycerin

• Propylene glycol

• PEG

What is the purpose of colorant and opacifer?

Provides aesthetic appearance

What are examples of colorant and opacifier?

• FD&C

• D&C lakes

• Iron oxide pigments

What is the vehicle in aqueous film coating?

Water

What is the film-forming polymer in non-aqueous film coating?

Cellulose acetate phthalate

What is the purpose of alloying substance?

Providing water solubility or permeability to the film to ensure penetration by body fluids and therapeutic availability of the drug

What is the alloying substance used in non-aqueous film coating?

PEG

What is used as a plasticizer in non-aqueous film coating?

Castor Oil

What is used as a surfactant in non-aqueous filming?

Polyoxyethylene sorbitan derivatives

What is the purpose of glossant in non-aqueous film coating?

Providing luster without a separate polishing operation

What is used as a glossant in non-aqueous film coating?

Beeswax

What is the purpose of a volatile solvent?

Allowing the spread of the other components over the tablets while allowing rapid evaporation to permit an effective yet speedy operation

What is an example of a volatile solvent?

Alcohol mixed with acetone

What is the purpose of enteric coating?

Intended to pass through the stomach intact to disintegrate and release their drug content for absorption along the intestines

What are issues with film coating?

• Sticking and picking

• Orange peel effect

• Bridging and filling

What is press coating and what is the purpose?

• Compaction of granular coating materials around a tablet

• Tablet within a tablet, needs a specialized tablet machine

• To separate incompatible drugs (in the core and coating layer) and to coat tablets containing solvent (water & organic solvent) sensitive drugs

What is a disadvantage of press coating?

Complex compressing machine required

What is capping?

Partial or complete separation of the top or bottom of the tablet from the main body

What is lamination?

Separation of the tablet into 2 or more distinct layers

What is picking?

A small amount of material from a tablet is being removed from the tablet surface and sticking to the punch face

What is sticking?

Tablet material adhering to the die wall

What is the double impression?

When the lower or upper punch has a monogram or other engraving

What is the reason for double impression occurring?

Some lower punch travels uncontrollably and make the print twice

What is mottling?

Unequal distribution of color on the tablet surface

What are the official tests?

• Weight variation

• Content uniformity

• Disintegration

• Dissolution

What are the non-official tests?

• thickness

• hardness

• friability

What are the 2 methods of weight variation test?

1. 10 tablets from 4 batches are weighed individually → calculating average weight → weight of each tablet should be within ±5% of average weight

2. Total of 20 tablets is weight individually → average weight → no more than 2 tablets can be outside of the range and none can differ by more than 2x % limit

How is thickness measured?

Thickness gauge, micrometer calipers

Individual thickness of 10 tablets should be within ±5% of the average thickness

How is hardness measured?

Hardness thickness

Typically between 4-10 kg

What is friability?

Tendency of a tablet to crumble

How is friability measured?

Measures the ability of a tablet to withstand abrasion during handling, packaging, and shipment by a friabilator

How is disintegration?

Time required by tablets to break up into particles that are small enough to pass through the #10 mesh screen

How are uncoated tablets tested for disintegration?

6 tablets at a time should all disintegrate into water within the time specified in the USP

If 1 or 2 fail, repeat with 12 more

16/18 must properly disintegrate

How is dissolution tested?

7 different types of dissolution testers, 2 apparatus (basket & paddle) and #30 mesh screen with 900 mL of fluid kept at body temperature

What is the simulated media for dissolution?

• Simulated gastric fluid, USP

• NaCl 2 g

• Pepsin 3.2 g

• HCl 7 ml

• Water qs to 1000 mL (pH 1.2)

What is in the simulated intestinal fluid?

• K2HPO4 6.8 g

• 0.2 N NaOH 190 mL

• Pancreatin 10g

• Water qs to 1000 mL (pH 7.5)