Tablets Flashcards
two types of solid dosage forms
disintegrating type
non-disintegrating type
Oral Tablets for Ingestion
Compressed tablets Multiple compressed tablets Chewable tablets Fast dissolving tablets Delayed action and enteric coat tablets Sugar and chocolate coated tablets Gelatin coated tablets Molded tablets
Advantages of Tablets
Accurate dosage Convenient Can be scored or coated Easy to administer Control release of active Economical to manufacture
Disadvantages of Tablets
Mistaken as candy
Formulation sometimes limited
Not useful of vomiting/unconscious patients
Difficulty swallowing
Components of a Tablet
Active ingredient
Excipients
Excipients used for tablet
Diluents/ fillers Binders Lubricants Gildants Anti-adherents Disintegrants
Provide bulk to a tablet formulation
Good compaction properties
Flow properties
Diluents or Fillers
Examples of Diluents or Fillers
Lactose USP
Microcrystalline cellulose
Modified dextrose
Factors Influencing Choice of Fillers
Compressibility Flowability Particle size and distribution Moisture content Bulk density Compatibility with active Solubility Stability Cost/availability Inertness Governmental acceptability
Promote adhesion of powder particles
Its concentration affects hardness and friability of tablet
Dry or liquid state
Binders
examples of binders
Starch Polyvinylpyrrolidone (PVP)*
Promotes break-up of tablet into smaller pieces after it has been swallowed
Disintegrating Agents
Disintegrating Agents Mechanism
absorb water and swell
______ affects rate of disintegration in Disintegrating Agents
Concentration
Prevent the formulation and formed tablet
from sticking to machinery
Lubricants
more efficient lubricants are water _____
insoluble
Improves flowability of powders/granulation.
Allows formulation to flow easily through tableting
machine
Glidants
In Glidants, flowability is measured using angle of ___ or
____
repose
Flowdex
Flavors and Sweeteners
Sprayed dried and other flavors
Natural sweeteners
Artificial sweeteners
Primary reason for using colors: ______
Marketing
Colors used
FD&C dyes
FD&C lakes
Iron oxides
Methods of Tablet Preparation
Direct compression
Wet granulation
Lugging (dry granulation)
Novel methods
the following are examples of novel method:
Fluid bed processing
Hot melt extrusion
Must be a free-flowing and compressible
formulation
direct compression
Improve compressibility, flowability, and
content uniformity of powder blend
Wet Granulation
Direct Compression may require ___ to improve flowability.
Problems with high dose drugs: ____
Problems with low dose drugs: ____
glidant
Compressibility
Uniformity
Improves compressibility, flowability, and content uniformity of powder blend
Wet granulation
Stainless steel chamber
Airflow causes continual movement
More efficient drying
Use apparatus to wet granulate and dry
Fluidized bed dryer
characteristics of Wet Granulation
Good for poor compressible powders Excellent flow Good content uniformity Stability problems Possible problems with disintegration Less sensitive to over-blended lubrication
What are the things in common between Wet granulation and direct compression
blending
premix
compression
Comparison of the Two Processes: wet granulation and direct compression
Direct Compression
- Faster dissolution
- Lower levels of disintegrants needed
- Increased cost of raw materials
Wet Granulation
- Produce harder tablets
- Slower dissolution
- Cost of equipment, time, labor, and energy
Which method does the following:
Compacts large masses of powder mixture
Crush and size pieces into smaller granules
Dry Granulation Method
Slugging
Properties of Good Tablets
- Physical Stability
- Chemical Stability
- Esthetic Appearance
- Bioavailability
- Weight and Content Uniformity
What is meant by Esthetic Appearance
Free of chips/cracks,
contamination, uneven
coloration
What is meant by Physical Stability
Remain whole during
manufacture/transport/
dispensing
Problems in Tableting
Capping Improper fill Picking or sticking Crumbling Mottled tablets Non-disintegrating tablets
In-Vitro Tests of Finished Tablets
Content uniformity Weight uniformity Tablet density and or diameter Hardness Friability Disintegration Dissolution
this type of testing does the following:
Operates by reciprocating action
A basket-rack device
Records time for disintegration
USP Disintegration Testing
Factors Affecting Disintegration
Addition of disintegrants
Manufacturing method
Pressure used for compression
Tablet hardness
A Round bottom flasks containing dissolution
media at 37C
USP Apparatus I (Basket) and II (Paddle)
In order to Pass the Dissolution Test, All six tablets dissolved at a value that is some % of the total dose, this is called
Q-value
Other Official Dissolution
Methods
USP method III, IV, V-VII,
Factors Affecting Dissolution
Particle size Solubility of drug in solvent Ph of solvent Rate of mixing temperature of media Excipients in formulation
Reasons for multiple compression tablets?
Separate incompatible components
Make each layer release at a different rate
Make each layer different color
Compressed tablets designed to be chewed.
Critical considerations in formulation-
Organoleptic properties
Chewable Tablets
Tablets designed to dissolve or disintegrate in
mouth in second
Fast-Dissolving Tablets
advantages of Fast-Dissolving Tablets
Good for people who have difficulty swallowing
disadvantages of Fast-Dissolving Tablets
Tablet is generally weak
Moisture sensitive
Reasons for using Buccal and Sublingual Tablets as delivery route?
drug destroyed by gastric fluid
drug poorly absorbed from GI tract
achieve rapid absorption (SL Nitroglycerin)
____ Used to produce
‘chocolate’ color
iron-oxides
Used to deliver anti-infective agents or hormones
Inserts Dispensed with applicator
Compressed tablets
Vaginal tablets
Effervescent Tablets advantages
Rapid disintegration
No dissolution problems
Mask taste
Effervescent Tablets disadvantages
Expensive
High sodium conc
Packaged in hermetically sealed containers
Special production facility
Tablet Triturates
- rapidly dissolved in water
- contain a small amount of potent drug, lactose or
sucrose as filler - fragile tablets
____ Tablets are Compress effervescent salts
Effervescent
some excipients required for effervescent tablets
Binders
Lubricants
Flavors/sweeteners
Acids used in effervescent tablets
citric acid
tartaric acid
salt used in effervescent tablets
bicarbonate
Official dissolution methods:
Reciprocating cylinder apparatus-
Flow through cell-
Transdermal patches-
USP method III
IV
V-VII
Examples of disintegrating agents
Starch and starch derivatives - croscarmellose starch and sodium starch glycolate
Examples of lubricants
Magnesium stearate*
Talc
Examples of glidants
Silica derivatives
Talc
