Pharmacology: Drug Delivery Systems

Drug Delivery Systems

• The release of API is under the control of the drug delivery system (temporal control)
• Advantages of controlled release: • Avoids fluctuations of plasma drug concentration for better safety and efficacy • Decreased frequency of drug administration (often once daily) for better compliance
• Types of controlled release: • Sustained release (SR) – release of the initial API dose and further prolonged release • Controlled release (CR) – properly controlled (Zero order) release of API

Capsules

• A capsule is a medication in a gelatin container
• Advantage: masks the unpleasant taste of its contents
• Types of capsules: • Hard-shelled capsules (for dry, powdered ingredients) • Soft-shelled capsules (for oils and active ingredients dissolved or suspended in oil)

Lozenges

• Solid preparation consisting of sugar and gum
• Used to medicate the mouth and throat for slow administration of indigestion or cough remedies

Pastilles

• Solid medicated preparations designed to dissolve slowly in the mouth
• Softer than lozenges, with bases made of glycerol and gelatin, or acacia and sugar

Dental Cones

• Tablet form intended to be placed in the empty socket following a tooth extraction
• Prevents the local multiplication of pathogenic bacteria associated with tooth extractions

Pills

• Oral dosage forms consisting of spherical masses prepared from one or more medicaments incorporated with inert excipients

Granules

• Solid, dry aggregates of powder particles often supplied in single-dose sachets
• Some granules are placed on the tongue and swallowed with water, others are intended to be dissolved in water before taking

Powders (Oral)

• Two kinds of powder intended for internal use: • Bulk Powders: multidose preparations consisting of solid, loose, dry particles of varying degrees of fineness • Divided Powders: single-dose presentations of powder (e.g., a small sachet) intended to be issued to the patient as such, to be taken in or with water

Powders for Mixtures

• Mixed powders may be stored in dry form and mixture prepared by the pharmacist when required for dispensing by suspending the powders in the appropriate vehicle

Liquid Preparations

• Solutions are traditionally one of the oldest dosage forms used in the treatment of patients
• Advantages: rapid and high absorption of soluble medicinal products

Topical Dosage Forms

• Lotions: fluid preparations (aqueous) for external application without friction
• Collodion: a solution of nitrocellulose in ether or acetone, sometimes with the addition of alcohols
• Paints: liquids for application to the skin or mucous membranes
• Pressurized dispensers (aerosol sprays): several different types of pharmaceutical product may be packaged in pressurized dispensers

Vaginal Dosage Forms

• Vaginal capsules: similar to soft gelatin oral capsules, differing only in size and shape
• Vaginal ring: 'doughnut-shaped' polymeric drug delivery devices designed to provide controlled release of drugs to the vagina over extended periods of time
• Douche: a device used to introduce a stream of water into the body cavity for medical or hygienic reasons
• Intrauterine device (IUD): a birth control device placed in the uterus, also known as a coil

Parenteral Dosage Forms

• Injections: infusion methods of putting liquid into the body, usually with a hollow needle and syringe
• Types of injections: • Intravenous injection: liquid administered directly into the bloodstream via a vein

Inhaled Dosage Forms

• Nebulizer or atomizer: a device used to administer medication to people in forms of a liquid mist to the airways
• Aerosol particles: size determines the speed of penetration into the respiratory tract

Ophthalmic Dosage Forms

• Eye drops: saline-containing drops used as a vehicle to administer medication in the eye
• Ophthalmic ointment and gel: sterile semi-solid preparations intended for application to the conjunctiva or eyelid margin

Otic Dosage Forms

• Ear drops: solutions, suspensions, or emulsions of drugs instilled into the ear with a dropper
• Used to treat or prevent ear infections, especially infections of the outer ear and ear canal