Pharmacy Orientation: Dosage Forms Overview

Pharmacy Orientation

• Course code: PT101
• Credit hours: 1
• Number of lectures: 6
• Department: Pharmaceutics and pharmaceutical technology

Introduction to Different Dosage Forms

• Images of various dosage forms (pills, capsules, liquid medication, etc.)

Pharmaceutical Dosage Forms

• Definition: Dosage forms are the forms in which a drug is taken by patients (tablets, capsules, injections).

Dosage Forms Classification

• Liquid Dosage Forms:
  • Solutions
  • Suspensions
  • Emulsions
• Solid Dosage Forms:
  • Tablets
  • Capsules
• Semisolid Dosage Forms:
  • Ointment
  • Cream
  • Paste
  • Gel
• Molded Dosage Forms:
  • Suppositories
  • Pessaries
• Sterile Dosage Forms:
  • Injections
  • Ophthalmics

Liquid Dosage Forms: Solutions

• Description: Preparations where solute particles (solid, liquid, gas) are dispersed in a liquid solvent.
• Uses: For internal or external therapeutic effects.
• Classification: Based on the vehicle:
  • Aqueous (water-based)
  • Non-aqueous (other solvents)

Liquid Dosage Forms: Solutions (Advantages)

• Faster therapeutic effect compared to tablets/capsules
• Easy administration, especially to children and the elderly
• Uniform dose delivery (no shaking is needed)

Liquid Dosage Forms: Solutions (Disadvantages)

• Bulky for transportation/storage
• Less stable compared to solid forms (potential for hydrolysis and oxidation)
• Difficult to mask unpleasant taste/odour

Aqueous Solutions:

• Description: Liquid preparations with one or more soluble chemical substances dissolved in water.
• Uses: Vehicle or solvent for medicinal ingredients.
• Advantages: Tasteless, odourless, non-irritating.
• Examples:
  • Aromatic water (medicated water, e.g., peppermint)
  • Syrups (sweet, viscous solutions of sugar or other sweetening agents in water, with or without flavorings)
  • Douches (used for cleansing or antiseptics of body parts)
  • Enemas (rectal injections for bowel evacuation)
  • Gargles (aqueous solutions with antiseptics/antibiotics/anesthetics to treat the pharynx/nasopharynx)
  • Mouthwashes (aqueous solutions with antibiotics and flavouring to prevent plaque/dental caries)
  • Nasal Solutions (for reducing nasal congestion)
  • Otic Solutions (for topical administration in the ear)

Non-aqueous Solutions

• Description: Solutions containing minor quantities of toxic solvents (benzene, acetone etc).
• Types:
  • External products: methanol, isopropanol, PEG, ethers.
  • Internal products: ethanol, glycol, oils.
• Examples:
  • Elixirs (pleasant, sweetened hydroalcoholic liquids for oral use), containing ethanol and water; often glycerin and sorbitol.
  • Spirits (hydroalcoholic solutions of volatile substances, 50-90% alcohol)

Liquid Dosage Forms: Suspensions

• Description: Two-phase system: insoluble solid dispersed in a liquid (oil or water).
• Properties of a good suspension:
  • Settling should be slow and redispersion easy after shaking
  • Particles should not cake
  • Viscosity suitable for pouring
  • Chemical stability and appealing appearance
• Components:
  • Drug
  • Liquid vehicle (usually water)
  • Wetting agents
  • Flocculating agents
  • Suspending agents
  • pH adjusting agents (buffers)
  • Flavoring agents
  • Sweeteners
  • Preservatives

Liquid Dosage Forms: Suspensions (Advantages)

• Used for insoluble drugs
• Improve taste of medication
• Used when the drug is unstable in aqueous solutions

Liquid Dosage Forms: Emulsions

• Description: Two immiscible liquids (oil and water) combined with an emulsifying agent; dispersed uniformly.
• Types:
  • Oil-in-water (O/W) - oil dispersed in water
  • Water-in-oil (W/O) - water dispersed in oil
• Components:
  • Internal phase (solute)
  • External phase (dispersion medium)
  • Emulsifying agent

Liquid Dosage Forms: Emulsions (Advantages)

• Mask unpleasant taste/odor of drugs
• Improve drug solubility
• Prolong the action of the drug

Liquid Dosage Forms: Emulsions (Disadvantages)

• Physical instability due to coalescence of dispersed globules
• Creaming or cracking of emulsion