INTRODUCTION
 Oral Solid Dosage Forms
The drug therapeutic indices could be maximized while indices of adverse reactions or side
effects could be minimized by regulating the drug release in body in a well-defined controlled
manner. This would eliminate the haphazard and uncontrolled blood plasma profiles of drugs
usually associated with conventional dosage forms. Tablets are solid medications that are
compacted into small, formed shapes. The mouth for oral administration usually takes tablets.
Tablets consist of several components. These components work together to ensure that the
tablet is properly digested in the body, is easy to swallow, has flavorings or sweeteners for
taste, and controls the timed release of the drug to produce the desired effect. All of the
ingredients except the active drug are called inactive or inert ingredients.
 Classification and Types of Tablets
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Oral Tablets for Ingestion
Compressed tablets
Multiple compressed tablets
Layered tablets
Compression-coated tablets
Repeat-action tablets
Delayed-action and enteric-coated tablets
Sugar and chocolate-coated tablets
Film coated tablets
Chewable tablets
2.
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Tablets Used in the Oral Cavity
Buccal tablets
Sublingual tablets
Troches and lozenges
Dental cones
3. Tablets Administered by Other Routes
 Implantation tablets
 Vaginal tablets
4.
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Tablets Used to Prepare Solutions
Effervescent tablets
Dispensing tablets
Hypodermic tablets
Tablet triturates
 DEFINITION [3]
Immediate release tablets are invented to disintegrate and release their dosage form with no
special rate controlling features, such as special coatings and other techniques. Immediate
release tablets are those, which disintegrate swiftly and get dissolved to release the
medicaments. The oral bioavailability of drug dependent on disintegration, dissolution and
various physiological factors. An immediate release dosage form helps a manufacturer to
diversify market and simultaneously offering patients a convenient dosage form or dosage
regimen.
 DIFFICULTIES WITH EXISTING ORALDOSAGE FORM [5][6][7]
1. Patient may suffer from tremors therefore they have difficulty to take powder and liquids. In
dysphasia physical obstacles and adherence to an oesophagus may cause gastrointestinal
ulceration.
2. Swallowing of solid dosage forms like tablet and capsules and produce difficulty for young
adult of incomplete development of muscular and nervous system and elderly patients suffer
from dysphasia.
3. Buccal and sublingual formation may cause irritation to oral mucosa, so patients refused to use
such medications.
4. Cost of products is main factor asparenteral formulations are most costly and discomfort.
 DESIRED CRITERIA FOR IMMEDIATE RELEASE DRUG DELIVERY SYSTEM
[4][5]
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Immediate release dosage form should In the case of solid dosage it should disintegrate or
dissolve in the stomach within a very less period.
In case of liquid dosage form the test masking is required
It should not leave less or no residue in the mouth after the oral administration.
Exhibit less sensivity to atmospheric condition as humidity and temperature.
Be manufactured using conventional processing and packaging equipment at low cost.
fast dissolution and absorption of drug, which may undergoes rapid onset of action.
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Advantages of Immediate Release Drug Delivery System [8]
Improved compliance / added convenience, solubility, stability, bioavailability.
Allows high drug loading, cost-effective.
Ability to provide advantages of liquid medication in the form of solid preparation.
Adaptable and amenable to existing processing and packaging machinery.
Decreased dissolution and disintegration times for immediate release oral dosage forms.
 Disadvantages of Immediate Release Tablets [9]
 Frequent dosing is necessary for a drug with a short half-life.
 Drug release at a time may produce high plasma concentration which may produce toxicity.
 Pharmaceutical Composition of Immediate release tablets [11][12][13]
 Binder
Binder is a material used to bind other materials together. Microcrystalline cellulose (MCC) is
commonly used as a filler-binder in direct compression because of its good bonding properties.
Other commonly used binders in direct compression include starches and their derivatives,
such as pregelatinised and granulated starches.
 Surfactants
One very useful class of excipients is surfactants, preferably present from 0 to 10 % w/w.
Suitable surfactants include fatty acid and alkyl sulfonates; commercial surfactants such as
benzalkonium chloride, dioctyl sodium sulfosuccinate, polyoxyethylene sorbitan fatty acid
esters, natural surfactants such as sodium taurocholic acid, lecithin, and other phospholipids
and mono and diglycerides; and mixtures thereof. Such materials can advantageously be
employed to increase the rate of dissolution by, for example, facilitating wetting, or otherwise
increase the rate of drug release from the dosage form.
 pH Modifiers
Inclusion of pH modifiers such as acids, bases, or buffers may also be beneficial in an amount
of from 0 to 10 % w/w. Acidic pH modifiers (e.g., acids such as citric acid or succinic acid)
retard the dissolution of the pharmaceutical composition when the dispersion polymer is
anionic. Alternatively, basic pH modifiers (e.g., sodium acetate or amines) enhance the rate of
dissolution of the same types of pharmaceutical composition.
 Diluents
Examples of other matrix materials, fillers, or diluents include lactose, mannitol, xylitol,
dextrose, sucrose, sorbitol, compressible sugar, microcrystalline cellulose (MCC), powdered
cellulose, starch, pregelatinized starch, dextrates, dextran, dextrin, dextrose, maltodextrin,
calcium carbonate, dibasic calcium phosphate, tribasic calcium phosphate, calcium sulfate,
magnesium carbonate, magnesium oxide, poloxamers, polyethylene oxide, hydroxypropyl
methyl cellulose (HPMC) and mixtures thereof.
 Lubricants
Examples of lubricants include calcium stearate, glyceryl monostearate, glyceryl
palmitostearate, hydrogenated vegetable oil, light mineral oil, magnesium stearate, mineral oil,
polyethylene glycol, sodium benzoate, sodium lauryl sulfate, sodium stearyl fumarate, stearic
acid, talc and zinc stearate.
 Glidants
Examples of glidants include silicon dioxide, talc and cornstarch. A glidant is a substance that
is added to a powder to improve its flowability. A glidant will only work at a certain range of
concentrations. Above a certain concentration, the glidant will in fact function to inhibit
flowability (which means that there's a critical concentration to be used if increasing powder's
flowability is intended with respect to the glidant and the powder properties). In tablet
manufacture, glidants are usually added just prior to compression.
 Disintegrants:
As disintegrants sodium starch glycolate, sodium carboxymethyl cellulose, calcium
carboxymethyl cellulose, croscarmellose sodium, Crospovidone, polyvinyl polypyrrolidone,
methyl cellulose, microcrystalline cellulose, powdered cellulose, lower alkyl-substituted
hydroxypropyl cellulose, polacrilin potassium, starch, pregelatinized starch, sodium alginate,
and mixtures thereof. The amount of disintegrant included in the dosage form will depend on
several factors, including the properties of the dispersion, the properties of the porosigen and
the properties of the disintegrants selected. Generally, the disintegrant will comprise from 1%
w/w to 25% w/w of the dosage form.
 EXCIPIENTS USED IN IMMEDIATE RELEASE DRUG DELIVERY SYSTEM [6][10]
Excipients balance the properties of the actives in immediate release dosage forms. This
demands a thorough understanding of the chemistry of these excipients to prevent interaction
with the actives. Determining the cost of these ingredients is another issue that needs to be
addressed by formulators. The role of excipients is important in the formulation of fast-melting
tablets. These inactive food-grade ingredients, when incorporated in the formulation, impart
the desired organoleptic properties and product efficacy.
 SUPER DISINTEGRANTS [14]
A disintegrant is an excipient, which is added to a tablet or capsule blend to aid in the breakup
of the compacted mass when it is put into a fluid environment.
1. Sodium Starch Glycolate (Explotab, primogel): used in concentration of 2-8 % & optimum
is 4%. Mechanism of Action: Rapid and extensive swelling with minimal gelling.
Microcrystalline cellulose (Synonym: Avicel, celex) used in concentration of 2- 15% of tablet
weight. And Water wicking
2. Cross-linked Povidone (crospovidone) (Kollidone): used in concentration of 2-5% of weight
of tablet. Completely insoluble in water. Mechanism of Action: Water wicking, swelling and
possibly some deformation recovery. Rapidly disperses and swells in water, but does not gel
even after prolonged exposure. Greatest rate of swelling compared to other disintegrants.
Greater surface area to volume ratio than other disintegrants.
3. Low-substituted hydroxyl propyl cellulose: which is insoluble in water. Rapidly swells in
water. Grades LH-11 and LH-21 exhibit the greatest degree of swelling. Certain grades can
also provide some binding properties while retaining disintegration capacity. Recommended
concentration 1-5% .
4. Cross linked carboxy methyl cellulose sodium: (i.e. Ac-Di-sol) Croscarmellose sodium:
Mechanism of Action: Wicking due to fibrous structure, swelling with minimal gelling.
Effective Concentrations: 1-3% Direct Compression, 2-4% Wet Granulation.
 Conventional Technique Used in the Preparation of Immediate Release Tablets
 EVALUATION PARAMETERS OF IMMEDIATE RELEASE TABLETS
 Compatibility studies
The proper design and formulation of a dosage form requires consideration of the physical,
chemical and biological characteristic of the ingredients used in fabricating the formulation i.e.
the drug and all the excipient used in the formulation. The drug and the excipients should be
compatible with one another to produce stable, efficacious, attractive and easy to administer
and safe dosage form.
 CONCLUSION