Pharmacology Lab 4: Dosage Forms

Dosage Forms (DFs)

• Dosage Forms are the means of delivering a drug molecule to the action site in the biological system to get an optimum desirable effect with the lowest adverse reaction.
• DFs can be classified according to the route of administration or physical form.
• Physical form classification includes: • Solid (tablets, capsules, powder, etc.) • Semisolid (ointments, creams, pastes) • Liquid (suspension, solutions, emulsion, etc.) • Gaseous (aerosols)

Aims of Preparing Different Dosage Forms

• Getting an accurate dose
• Protecting the drug from gastric juice
• Masking taste and odor
• Placing drugs within body tissues
• Sustaining and controlling a drug release
• Optimizing a drug action
• Inserting drugs into body cavities (e.g., rectally)

Selection of a Suitable Dosage Form

• Depends on the physicochemical properties of a drug (e.g., acid or base)
• Depends on the site of desired drug action (local or systemic)
• Depends on the required onset of response (fast or slow response)
• Depends on the rate and extent of drug absorption (from different routes)
• Depends on the state of the patient (e.g., conscious or not)

Solid Dosage Forms

• Tablets: • Consist of active ingredient and excipients in a predetermined ratio • Excipients can include diluents, binders, granulating agents, flow aids, lubricants, disintegrants, sweeteners, and pigments • Can be coated to make it smoother, more resistant, control release rate, enhance appearance, or mask bitter taste
• Types of tablets: • Scored tablets • Sugar-coated tablets • Enteric-coated tablets • Slow-release tablets • Caplets • Effervescent tablets • Chewable tablets
• Capsules: • Hard gelatin capsules • Soft gelatin capsules
• Lozenges: • Solid preparations formed from sugar base • Contain drug and other flavors • Designed to dissolve slowly in the mouth and release drug topically
• Dental cones: • Tablets applied in empty sockets following tooth extraction • Contain antibiotic or antiseptic material
• Powders: • Finely ground form of an active drug
• Granules: • Consisting of solid, dry aggregates of powder particles
• Suppositories: • Solid base of glycerin or cocoa butter containing a drug • Manufactured in appropriate size for rectal and vaginal use

Semisolid Dosage Forms

• Creams: • Semisolid emulsions of water and oil
• Ointments: • Strong emollients • Contain no water • Less skin penetration than creams
• Pastes: • Mixture of powder and ointment • Less penetrating than ointment • Make a good protective barrier when placed on the skin
• Gels: • Semisolid system consisting of dispersion of small or large molecules in an aqueous liquid vehicle • Rendered to jelly-like by adding a gelling agent

Liquid Dosage Forms

• Elixirs: • Clear, sweetened hydro-alcoholic solutions • Flavoring agents can be added to enhance palatability
• Syrups: • Concentrated aqueous solution of a sugar • Usually sucrose • Contain medicaments and flavoring agents • Sweeter and more viscous than elixirs
• Suspensions: • Contain fine and undissolved particles of a drug suspended in a liquid base • Need to shake the suspension bottle well before use to evenly distribute the drug particles
• Tinctures: • Alcoholic preparations containing the active principals of vegetable drugs • Can be topically applied, e.g., tincture of iodine
• Emulsions: • Suspension of fat particles in a watery base
• Lotions: • Topically applied suspension of an active drug in a water base • Usually, some skin-moisturizing agent is added
• Injections: • Method of putting liquid into the body, usually with a syringe • Methods of injection include: • Intravenous (IV) injection • Intramuscular (IM) injection • Subcutaneous (SC) injection
• Infusion therapy: • Involves the administration of medication through a needle or catheter • Consists of a diluted solution that contains readily soluble constituents of crude drugs
• Drops: • Different types, such as eye, nasal, and ear drops
• Gargles: • Aqueous solutions used in the prevention or treatment of throat infections
• Mouthwashes: • Similar to gargles but used for oral hygiene and to treat oral infections
• Extracts: • Concentrated preparations containing the active principals of vegetable or animal drugs

Gaseous Dosage Forms

• Gaseous dosage forms can be either as liquid or powders, which are packed in a canister that gets released upon applying pressure
• The gas inside contains the active ingredient
• Valve systems with continuous or limited delivery should be used within the containers
• Used for topical application on skin and as local application into nose, mouth, and lungs
• Packed and dispensed in: • Sprays • Liquid sprays: solutions of a drug combined with water or alcohol