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are compressed solid unit dosage forms containing medicament usually circular in shape and may be flat or biconvex.
prepared by compression with a limited number prepared by
molding
Tablets
are mainly incorporated to enhance physical appearance, stability, disintegration, or breakup of tablet after
administration
Additives or excipients
Some tablets are ______________, which allows them to be easily broken into two or more parts
Some tablets are scored, or grooved, which allows them
to be easily broken into two or more parts
Advantage of Tablets
1.Accuracy in dose.
2.Increased physiological activity, physical and chemical stability.
3.The ease of administering.
4.Economic production on a large scale.
5.Simple to handle, and transport.
6.Special forms, such as sustained-release pills, help patients
comply.
Disadvantages of Tablets
1.Unsuitable for patients who cannot swallow, including
newborns and youngsters.
2.A slower beginning of action than with liquids, oral
medications, and parenteral.
Types of Tablets:
- Compressed tablets
- Multiply Compressed Tablets
- Sugar coated tablet
- Film-coated tablets
- Gelatin-coated tablets
- Enteric-coated tablet
- Buccal and Sublingual tablets
- Chewable tablets
- Effervescent tablets
- Molded tablets
- Hypodermic tablet
- Tablet triturates
- Dispensing tablets
- Immediate-release tablets
- dissolving tablets
- Extended-Release tablets
- Vaginal tablets
▪ Prepared by compression of powdered crystalline or granular materials by the application of high pressures using punches and die.
- They do not contain special coatings.
▪ Rapid disintegration occurs which releases the drug rapidly
Compressed tablets
_________ are fillers that provide a formulation volume it needs to create tablets of proper size.
Diluents are fillers that provide a formulation volume it needs to create tablets of proper size.
_________________ are made with anti-adherents, glidants, lubricants & other lubricating substances that increase material flow into tablet dies, lessen wear on punches & dies, prevent fill material from adhering to punches & dies.
Sheen-coated tablets are made with anti-adherents, glidants, lubricants & other lubricating
substances that increase material flow into tablet dies, lessen wear on punches & dies,
prevent fill material from adhering to punches & dies.
_________________ are colorants and flavorants
Miscellaneous adjuncts
▪The loaded material is compressed more than once to create tablets that have been multiply compressed.
▪The outer tablet is shell, & inner tablet is core.
▪Due to physical and chemical incompatibilities, each layer
contains a distinct therapeutic ingredient.
Multiply Compressed Tablets
▪ A colored sugar layer may be applied to compressed tablets.
▪ After being swallowed, the coating soon dissolves because it is water soluble.
▪ The sugarcoats shield medicine inside from outside elements & act as a defense against unpleasant tastes and odors.
▪ It enhances the appearance of the tablet.
▪ Permits imprinting of identifying manufacturers information
▪ Disadvantage: Time and expertise required in the coating process and increase in size, weight and shipping cost (May add 50% of the weight)
Sugar coated tablet
▪ It is the actual start of the sugar coating process
▪ It provides the rapid build-up necessary to round up the tablet
edge.
▪ It also acts as the foundation for smoothing and color coats.
Subcoating
▪ This process is for filing the irregularity/roughness on the surface generated during sub-coating.
▪ It also increases the tablet dimension to a predetermined level.
▪ usually can be accomplished by the application of a simple syrup solution of approximately 60 to 70% sugar
solid.
▪ This syrup solution generally contains pigments starch gelatin
acacia or opacifier (TiO2) if required.
Smoothing
▪ It involves the multiple application of syrup solution
containing the requisite coloring matter.
▪ Water-soluble dyes were used previously in the sugar coating
as water-soluble dye migrates to the surface during drying
they are now replaced by water-insoluble pigment forms, for example, TiO2, Iron oxide, and Certified Lakes.
Coloring (Color coating)
▪ Sugar-coated tablets use this process to achieve a final elegance.
▪ It is the application of a thin layer of glossy wax.
▪ The wax may be dissolved in warm naphtha or petroleum
benzene.
Polishing
▪ are a particular kind of oral medicine formulation that has a compressed tablet core that is then thinly coated with a glossy, water-soluble polymer, like hydroxypropyl methylcellulose.
▪ The coating is usually colored to enhance the appearance of the tablet and facilitate identification by patients.
▪ The primary goal is to shield the tablet core from external elements including moisture, light, and air that can degrade the drug’s efficacy and stability.
▪ It can also make swallowing easier by masking
the drug’s unpleasant taste or odor.
▪ It has an advantage over sugarcoatings in that it is more durable, less bulky, and less time consuming to apply
▪ By its composition, the coating is designed to rupture and expose the core tablet at the desired location in the
gastrointestinal tract.
Film-coated tablets
▪ Tablets that are coated in sugar are a recent innovation.
▪ The ground-breaking item, gelcap, is a compressed tablet in shape of a capsule that makes it possible for the coated product to be around one-third smaller than a capsule containing an equivalent amount of powder.
▪ In comparison to unsealed capsules, its coating makes swallowing easier and is more tamper-evident.
Gelatin-coated tablets
have a delayed release function.
▪ They are made to be ingested through the intestines, where the tablets dissolve and allow for absorption of the medication.
▪ are employed when the drug substance is destroyed by gastric acid or is particularly irritating to the gastric mucosa or when bypass of the stomach enhances drug absorption
Enteric coated tablets
▪ are flat, oval, and designed to
dissolve in the buccal pouch or under the tongue for oral mucosal absorption.
▪ They allow for oral absorption of medications that are either poorly absorbed by GIT & eliminated by gastric juice.
▪ are designed to erode slowly, and dissolved promptly and provide rapid drug effects
Buccal and Sublingual tablets
▪ are designed to disintegrate quickly and smoothly when chewed and dissolved in the mouth.
▪ They typically have a creamy base, often flavored and colored with mannitol.
▪ It is especially useful for administration of large tablets to children and adults who have difficulty in swallowing solid
dosage form
Chewable tablets
▪ Prepared by compressing granular effervescent salts that release gas when in contact with water.
▪ These tablets contain medicinal substances that dissolve rapidly when added to water.
▪ The “bubble action” can assist in breaking up the tablets and
enhancing the dissolution of the active drug
Effervescent tablets
▪ Some tablets are prepared using a molding process, such as tablet triturates, instead of compression.
▪ These tablets are usually soft, soluble, and designed for rapid
dissolution.
Molded tablets
▪ are small, usually cylindrical, molded, or compressed tablets containing small amounts of usually potent drugs.
▪ must be readily and completely soluble in water, only a minimal amount of pressure is applied during their manufacture.
▪ A combination of sucrose and lactose is usually the diluent
Tablet triturates
▪ Originally used by physicians in extemporaneous preparation of parenteral solutions.
▪ The required number of tablets was dissolved in a suitable vehicle and sterilized, and the injection was performed.
▪ The tablets were a convenience, because they can be carried by the physicians medicine bag and injections prepared to meet the needs of the individual patients.
▪ However it is difficult to achieve sterility and the availability of prefabricated injectable products,
Hypodermic tablet
▪ The use of this has ended.
▪ Because pharmacists used them to compose prescriptions,
they might be better known as compounding pills.
▪ They were not given to patients directly.
▪ The tablets contain large amounts of highly potent drug
substances, so the pharmacist could rapidly obtain premeasured amounts for compounding multiple dosage
units.
▪ These tablets had the dangerous potential of being
inadvertently dispensed as such to patients.
Dispensing tablets
▪ It is designed to disintegrate and release their medication with no special rate-controlling features, such as special coatings and other techniques
Immediate-release tablets
▪ Characterized by disintegrating or dissolving in the mouth within 1 minute, some within 10 seconds.
▪ Tablets of this type are designed for children and the elderly or for any patient who has difficulty in swallowing tablets.
▪ It liquefies on the tongue, and the patient swallows the liquid
Rapidly disintegrating or
dissolving tablets.
▪Sometimes called CRT are designed to release their
medication in a predetermined manner over an
extended period
Extended-Release tablets
▪ Uncoated, bullet shaped, or ovoid tablets inserted into the vagina for local effects.
▪ They are prepared by compression and shaped to fit
snugly on plastic inserter devices that accompany
the product.
▪ They contain antibacterials for the treatment of nonspecific vaginitis caused by Haemophilus vaginalis or antifungals for the treatment of
vulvovaginitis candidiasis caused by Candida albicans.
Vaginal tablets
▪ Also known as fillers or bulking agents.
▪ Used for making up of required bulk for a tablet
▪ Mostly used when dose of drug is too small to formulate as a tablet. If the dose is high, bulking agents are avoided.
▪ Properties of an ideal diluent: physiologically inert, non-toxic,
physically and chemically stable, easily available, free from microbial contamination, and does not affect the bioavailability of drug.
DILUENTS
Examples of diluents:
▪ Example: Lactose, Spray dried lactose, Mannitol, Dextrose,
Starch, Sorbitol, Sucrose, and Microcrystalline cellulose
▪Most widely used diluent
▪Available in hydrous and anhydrous form
▪Preferred because of pleasant taste
▪Readily dissolvable in water
▪Low cost and less disintegration time
▪Disadvantage: Undergo discoloration when in contact
with amine drugs
Lactose
▪ Can be used for direct compression due
to its cohesive nature and good flow characteristics.
▪ In presence of moisture, it may undergo darkening
Spray dried lactose
▪ Widely used as a diluent in chewable tablet
▪ Non-hygroscopic and non-carcinogenic
▪ Disadvantage: Expensive
Mannitol
▪Available in hydrous and anhydrous form
▪When combined with spray dried lactose, its darkening can be avoided
Dextrose
▪Very occasionally used as diluent
▪USP grade of this can be used due to its free flowing nature and direct compressibility
Starch
▪Suitable for direct compression
Sucrose
▪two main grades are available but they are expensive, so used in combination with other
diluents.
Microcrystalline cellulose
- Adhesives
▪ When mixed with powders, they are used to produce granules
▪ Enhance the free flowing capacity of granules of desired size and
hardness
▪ Selection of binders depends on the type of tablets
▪ For example: Lozenges requires more binders than tablets
▪ Gum acacia
▪ Tragacanth
▪ Starch paste
▪ Sucrose solution
▪ Polyvinylpyrolidine
▪ Gelatin
Cellulose derivatives like HPMC and HEC
Binders
-used alone in a concentration of 10-25% or in combination
Gum acacia and tragacanth
-should be prepared fresh and added in warm condition to avoid solidification
Gelatin
-is prepared by dispensing starch into cold purified
water, warming the mixture by continuous stirring until a translucent paste is formed.
Starch paste
-is used as a wet binder which is cheap, produces hard but brittle granules. Disadvantage: susceptible to microbial contamination
Sucrose solution
-used in aqueous or alcoholic solution and suitable for moisture sensitive drugs
PVP
-natural polymer as binder
Cellulose derivatives