Lecture 8- Tableting III Flashcards
Potential problems in tableting
*speed of compaction= mechanical feeding of the materials from the hopper into the die
^increased the problems because of the complexities of the presses and the greater demands on quality
Manufacturing problems
-capping + laminating
-sticking, picking and filming
-chipping and cracking
-mottling
Capping
Occurs when the upper segment of the tablet separates from the main portion of the tablet + comes off as a cap
Causes related to formulation;
-large amount of fines in granulation
-too dry
-granules not dry enough
-insufficient amount of binder/improper lubricant
Remedies;
-remove some/all fines
-moisten the granules/add hygroscopic substance
-dry the granules properly
-increase amount of binder/lubricant
Causes and remedies of capping due to machinery; Capping
Causes;
-poorly finished dies
-deep concave punches
-lower punch remains below the face of die during ejection
-high compression speed
Remedies;
-polish dies properly
-use flat punches
-make proper setting of lower punch during ejection
-reduce speed of compression
Lamination
Separation of the tablet in two or more distinct layers
Causes related to formulation;
-oily/waxy materials in granules
-too much of hydrophobic lubricant
Remedies;
-modify mixing process; add absorbent/adsorbent
-use lower amount of lubricant/change type
Causes and remedies of capping due to machinery;
Lamination
Causes;
-rapid relaxation of the peripheral regions of a tablet
-rapid decompression
Remedies;
-use tapered dies
-use pre-compression step; reduce turret speed + final compression pressure
Further; slide 12 + 13= picking
Mottling
Unequal distribution of colour with light/dark spots standing out in a uniform surface
Causes;
-coloured drug along with colourless/white-coloured excipients = use appropriate colourants
-dye migration during granule drying process= change solvent, binder + reduce drying temp
-improperly mixed dye= mix properly to prevent segregation
Quality control tests of tablets
*weight uniformity and content uniformity test= tablet should include correct dose of drug
*disintegration test and dissolution test= tablet should disintegrate + drug should be released in a controlled + reproducible way
*hardness + friability test= tablet should show sufficient mechanical strength to withstand fracture and erosion during manufacturing, packaging and handling
Quality control tests for tablets
*Compendial QC tests;
1. Uniformity of content of active ingredient
2. Friability
3. Disintegration test
4. Dissolution test
*Non-compendial tests;
-tablet thickness, hardness + tensile strength
Uniformity of content of active ingredient
-ensure a constant dose of drug between individual tablets
-dose variation tested in two ways
*uniformity of weight + *uniformity of content
=more on slide 17-27
Potential causes of weight variation
-size and distribution of the granules being compressed (presence of too large/fine granules)
-poor flow + mixing (incomplete filling of die/ not well distributed)
-lower punches of unequal lengths
Friability, disintegration + dissolution tests
Slides 29-37
Non-compendial testing
Crushing strength: compressional force applied diametrically to a tablet which just fractures it
Tablet diameter + thickness affect the force necessary to break it
Hardness tester
Oral tablets= hardness of 4-10kg
Hardness can affect tablet disintegration time
Too hard= may not disintegrate in time
Factors affecting tablet hardness;
-compression force + speed
-binder & its concentration
-lubricant
-method of granulation; wet granulation = harder tablets
Tablet thickness
-thickness of the tablet = only dimensional variable related to the tablet compression process
-measured with a micrometer
