Tablets & Types of Tablets

Main ideas and lessons

• The video is an introductory lecture on solid dosage forms, focusing on tablets and covering:
  • types
  • formulation and excipients
  • advantages/disadvantages
  • evaluation considerations
  • stability/destabilization issues (especially for coated and moisture-sensitive forms)
• Tablets are emphasized as a highly versatile, widely used, unit-dosage system that is:
  • precise (dose-to-dose uniformity)
  • convenient/portable
  • stable and scalable for manufacturing
• Tablet design is driven by drug properties and physicochemical behavior in the body, including how physiological factors and environmental conditions (e.g., GI pH, gastric emptying, moisture) affect performance.
• Many tablet types exist to achieve release control and targeting, including:
  • immediate vs delayed vs sustained/controlled release
  • local vs systemic effects
  • specialized routes (buccal/sublingual, vaginal, dental, implantable)

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Foundations: what tablets are and why excipients matter

Tablet definition

• Tablets are solid dosage forms containing:
  • an active pharmaceutical ingredient (API)
  • excipients

Excipients (examples mentioned)

• Diluents: increase bulk
• Binders: help hold the tablet together
• Disintegrants: promote breakup/disintegration
• Coloring agents
• Buffering agents
• Preservatives
• Odorifiers

Other functional roles are implied, such as coating polymers for release control.

General manufacturing approach

• Tablets are generally made via compression techniques:
  • combine API with excipients (binders, disintegrants, lubricants, etc.)
• Tablets may be:
  • uncoated
  • coated, for purposes like:
    • taste masking (e.g., bitter APIs)
    • protection from environment (e.g., pH extremes)
    • controlled release of medicament

Purposes of tablet formulation

• Immediate release
• Extended/sustained release
• Targeted delivery to specific tissues/regions

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Advantages vs disadvantages of tablets

Advantages

• Unit dosage form with high precision and low content variability
• Cost-effective
• Lightweight and compact
• Easy/economical packaging and transportation
• Generally stable (solids are less prone to degradation)
• Simple product identification (e.g., embossed/monogram)
• Coated tablets can:
  • be easier to swallow
  • reduce stomach sticking
  • enable specialized release (delayed/enteric)
• Strong suitability for large-scale mass production
• Better stability against chemical, physical, and microbiological degradation compared with many other dosage forms

Disadvantages / limitations

• Some drugs are not compressible (e.g., amorphous, low density, “fluffy” characteristics)
• Poorly wetting drugs (slow dissolution) are less suitable
• Drugs requiring high GI absorption may be hard to formulate with adequate bioavailability
• Bitter/odor-sensitive drugs or those sensitive to oxygen/moisture may require:
  • encapsulation/entrapment/coating
• Capsules may be a better alternative when coating/moisture sensitivity is problematic

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Tablet types (with uses, mechanisms, advantages, limitations)

Below is the structured list of tablet types described.

1) Compressed Tablets (uncoated)

Manufacturing methods (3 basics)

• Wet granulation
• Double compaction
• Direct compression

Purpose

• Rapid disintegration and quick drug release
• Often used for local GI tract effects

Mechanism (general)

• Tablet dissolves/disintegrates rapidly → drug releases locally and/or systemically

Applications/examples

• Local therapeutic categories: antacids, adsorbents
• Systemic categories: drugs with aqueous solubility → dissolve after disintegration → absorbed in GI → distributed

Advantages

• Rapid release; local/systemic effect as required

Limitations

• Mentioned more broadly: wetting/dissolution and bioavailability issues can make some drugs unsuitable

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2) Multiple Compressed Tablets (layered)

Structure

• Tablet contains multiple layers, each layer with a different component

Mechanism/processing

• Layers are sequentially added:
  1. compress first layer lightly
  2. add next powder/granules
  3. compress again
  4. repeat for additional layers
  5. final compression to target hardness

Uses

• Separate physically/chemically incompatible drugs
• Sometimes used for fixed-dose combinations
• Enable repeat-action/prolonged-action behavior

Advantages

• Functional separation of reactive ingredients for stability
• Can support sustained release via layers dissolving in different environments:
  • one layer dissolves in gastric juice
  • another dissolves in intestinal juice

Limitations

• Slower production than standard compressed tablets due to multiple precise compressions
• Repeat-action performance depends on gastric emptying, affecting release profiles

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3) Chewable Tablets

Design

• Intended to be chewed, not swallowed whole
• Often contain sugars or flavors

Uses

• For patients with swallowing difficulties (pediatric and geriatric noted)
• Common in products such as antacids

Mechanism

• Chewing increases surface area and reduces particle size in the mouth
• Enhances antacid performance by enabling faster dissolution/neutralization

Advantages

• Better acceptance by children and elderly
• Improved acid neutralization (especially for antacids)

Limitations

• Bitter-tasting drugs not suitable due to taste-masking requirements

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4) Sugar-coated / Chocolate-coated Tablets

Purpose

• Aesthetic appearance
• Easier swallowing
• Taste masking and odor masking
• Separating incompatible components (mentioned as a function)

Uses

• Historically common for multivitamins and medicines with reactive ingredients

Advantages

• Glossy “elegant” finish improves patient compliance
• Can reduce risk of degradation for sensitive ingredients
• Appealing appearance leads children to treat them like candy

Limitations / considerations

• Requires careful storage
• Traditional production is labor-intensive and time-consuming

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5) Film-coated Tablets

Design

• Thin polymer coating
• Used for:
  • taste masking
  • protection
  • controlled drug release
• Can be water-based or solvent-based depending on needs

Uses

• Works for both immediate and controlled release
• Presented as an alternative to sugar coatings (sugar coatings restricted due to diabetes risk)

Advantages

• Stronger coating with minimal weight increase
• Debossed markings remain visible; embossing/printing remains easy
• Tasteless coating reduces risk of “candy mistakes”

Limitations

• Less visually appealing than sugar coatings
• Needs advanced machinery and expertise

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6) Repeat-action Tablets

Design

• Delivers an initial dose followed by a second dose
• Often multiple compressed tablets or sugar-coated tablets

Mechanism

• Staged release in GI tract:
  • core coated with enteric polymers (e.g., shellac) to delay stomach release
  • sugar coating helps ensure second dose delivery at the right time/location

Advantages

• Better for staged GI release
• Useful when a repeat dose must occur over time

Limitations

• Subject to gastric emptying → affects release profile
• Requires interruptions during coating operations for dosage accuracy

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7) Delayed-action and Enteric-coated Tablets

Design

• Release after delay or after passing specific GI regions

Enteric-coated mechanism (most common)

• Remain intact in the stomach → release in the intestine

Uses

• For drugs unstable in gastric environment
• For drugs that can irritate gastric mucosa
• Also used in veterinary contexts to target lower GI regions (caecum/large bowel)

Advantages

• Protect drugs from gastric acid degradation (example: erythromycin)
• Minimize irritation from acidic medicaments (example: aspirin for arthritic patients)
• Deliver intestinal antibacterial agents or vermifuges undiluted at the target site

Limitations

• Requires specialized polymers such as:
  • cellulose acetate phthalate
  • polyvinyl acetate phthalate
• Requires careful evaluation of bioavailability, distribution, and pharmacokinetics due to altered release

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8) Controlled release Tablets

Design goal

• Provide sustained/controlled release over extended periods

Benefits

• Maintains therapeutic bloodstream levels longer
• Reduces dosing frequency

Mechanisms mentioned

• “Metered release” via coatings:
  • immediate release followed by sustained release
• Examples/innovations:
  • Theo-Dur: nearly linear release profiles; maintains narrow therapeutic range
  • Alza Oros: uses osmotic pressure for zero-order release
  • Film coating can enable diffusion-controlled release

Limitations

• Matrix tablets may not match particulate capsule release control
• Capsules may be preferred in controlled release due to public/marketing bias
• Requires advanced formulation techniques to achieve desired release profiles

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9) Buccal and Sublingual Tablets

Placement/route

• Buccal: cheek pouch
• Sublingual: under the tongue

Design constraints

• Typically small, flat tablets
• Dissolve over 15–30 minutes
• Require drugs with very high solubility and absorption characteristics

Mechanism

• Rapid absorption into systemic circulation
• Helps bypass first-pass metabolism
• Avoids degradation in gastric acid environment

Advantages

• Avoids first-pass metabolism → better bioavailability
• Faster onset compared with swallowed tablets (which disintegrate then dissolve)

Limitations

• Requires strong oral mucosa absorption
• Bland excipients needed to reduce salivation and support swallowing (implicit)

Examples/use cases

• Systemic delivery with rapid onset (e.g., vasodilators)
• Good for drugs that degrade in the stomach or cause nausea when swallowed

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10) Troches and Lozenges

Purpose

• Local action in mouth/throat

Dissolution/erosion

• Dissolve/erode slowly (≤ ~30 minutes mentioned)

Types

• Lozenges: flavored sugar bases
• Troches: produced by compression

Uses

• Sore throats
• Cough/colds (during cold symptoms)
• May include antiseptics, anesthetics, antitussives

Advantages

• Prolonged contact with affected area improves effectiveness
• Flavor base masks unpleasant taste

Limitations

• Not for systemic drug delivery
• May not provide immediate relief due to slow dissolution and hard nature

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11) Dental Cones

Design

• Small tablets placed in tooth extraction sockets
• Dissolve/erode over 20–40 minutes
• Release antibacterial or coagulant agents

Uses

• Prevent bacterial growth in extraction sockets
• Reduce post-extraction bleeding (via coagulant agents)

Advantages

• Localized action while avoiding systemic effects
• Provides controlled/sustained release

Limitations

• Must avoid components that promote bacterial proliferation
• Limited to dental applications

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12) Implantable Tablets

Design

• Small cylindrical or rosette-shaped tablets
• Implanted subcutaneously
• Provide prolonged release from 1 month to 1 year

Uses

• Growth hormones in food-producing animals
• Implantation locations noted: ear (to prevent tissue toxicity)

Advantages

• Very prolonged drug release
• Reduced frequency of administration
• Limited use in humans due to surgical requirements

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13) Vaginal Tablets

Design

• Ovoid or pear-shaped tablets
• Slow dissolution in the vaginal cavity
• Often buffered to maintain favorable pH

Uses

• Vaginal infections
• Steroid delivery for systemic absorption

Advantages

• Localized treatment
• Low drug release rate → higher efficacy and compatibility

Limitations

• Requires pH compatibility to avoid irritation
• Dissolution rate must match therapeutic needs/body parameters

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14) Effervescent Tablets

Design

• Rapidly dissolve in water and release CO₂
• Uses reaction of:
  • organic acids (citric or tartaric acid)
  • sodium bicarbonate

Mechanism

• Produces carbonated, pleasantly flavored clear solution
• Helps mask taste of certain drugs

Uses

• Drugs like aspirin and saline cathartics
• Suitable for drugs soluble in neutral/slightly alkaline pH

Advantages

• Allows extemporaneous preparation of accurate dosage
• Reduces gastric irritation for aspirin-like drugs
• Easy/quick administration of soluble drugs

Limitations

• Moisture-sensitive; can destabilize
• Requires hermetic packaging and specialized manufacturing

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15) Dispensing Tablets (for solution preparation)

Design

• Tablets dissolved into a specific volume of water to prepare a drug solution

Uses

• Antiseptic solutions (example: bichloride of mercury; mild silver proteinate)
• May include buffers or isotonic agents for wound contact/mucosal applications

Advantages

• Precise drug concentrations in solution form
• Easy to use

Limitations

• Not sterile
• Potential safety risk from toxic components (e.g., mercury) → needs careful labeling/packaging

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16) Hypodermic Tablets

Design

• Solid tablets containing drugs + water-soluble excipients for extemporaneous injectable solution preparation

Uses / historical context

• Historically prepared by physicians (especially in rural areas)
• Portable because solid tablets are easy to transport

Advantages

• Flexibility to prepare on-site injections in field practice

Limitations

• Risk of non-sterility
• Becoming obsolete with increasing technological advancements

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17) Tablet Triturates

Design

• Small cylindrical tablets made by molding or compression
• Often include lactose + binder like acacia
• For potent drugs requiring customized preparation by pharmacists

Uses

• Previously common for potent drugs needing individualized small-dose preparation

Advantages

• Pharmacists can prepare tailor-made formulations
• Supports individualized therapy

Limitations

• Poor content uniformity and friability (manual preparation)
• Rarely used today due to:
  • concerns about bioavailability
  • availability of pre-formulated dosage forms

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Conclusion / takeaway points

• Tablets are one of the most versatile and widely used drug delivery methods.
• Different tablet types were developed through years of research; the “type list” is not final.
• Future improvements may focus on optimized sustained/controlled release that is stable and scalable.
• Core takeaway:
  • tablets offer precise dosing, dose uniformity, and high usability compared with some semi-solid/liquid dosage forms.

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Speakers / sources featured

• No individual speakers, names, or institutions are explicitly identified in the provided subtitles.