Pharmaceutics: Dosage Forms and Drug Delivery

• Pharmaceutics is the branch of pharmacy focused on converting new chemical entities (NCEs) or existing drugs into safe and effective medications for patients.
• It can also be defined as the science behind designing dosage forms.
• Pharmaceutics encompasses the formulation, manufacturing, stability, and effectiveness of various pharmaceutical dosage forms.

Key Areas in Pharmaceutics

• Drug delivery involves designing systems to release drugs within the body.
• Drug action entails studying drug interactions with the body at a molecular level.
• Disposition investigates the absorption, distribution, metabolism, and excretion (ADME) of drugs.
• Dosage form design focuses on creating pharmaceutical products that are both effective and safe.
• Pharmacokinetics is the modeling of drug movement within the body.
• Biopharmaceutics examines the factors affecting a drug's bioavailability in humans or animals, using this to optimize the drug's therapeutic activity in clinical settings.

Dosage Forms

• Dosage forms are pharmaceutical products marketed for use, containing a specific combination of active and inactive ingredients in a particular configuration (e.g., tablet, capsule, solution, cream).
• Tablets are solid dosage forms created through compression.
• Capsules are solid dosage forms where medicinal agents are enclosed in a gelatin shell.
• Solutions are liquid preparations with one or more dissolved drug substances in a suitable solvent or miscible solvent mixture.
• Suspensions are liquid preparations with solid particles dispersed throughout a liquid phase.
• Emulsions involve a dispersion of one liquid within another immiscible liquid.
• Creams are semisolid emulsions.
• Ointments are semisolid preparations for external application on the skin.
• Gels are semisolid systems with small or large molecules dispersed in an aqueous liquid vehicle and rendered jelly-like by a gelling agent.
• Aerosols are pressurized dosage forms containing active ingredients that, upon activation, release a fine dispersion of liquid and/or solid materials in a gaseous medium.

Formulation

• Formulation includes the selection of appropriate ingredients, such as the active pharmaceutical ingredient (API) and excipients, and the determination of the manufacturing process to yield a stable and effective dosage form.
• Key considerations in formulation are drug solubility and stability.
• Key considerations in formulation are particle size.
• Key considerations in formulation are polymorphism.
• Key considerations in formulation are the compatibility of ingredients.
• Key considerations in formulation are the manufacturing process.
• Key considerations in formulation are the route of administration.
• Key considerations in formulation are the target patient population.

Manufacturing

• Pharmaceutical manufacturing involves a series of unit operations.
• Milling reduces the particle size of solid materials.
• Mixing combines multiple ingredients to achieve a homogenous mixture.
• Granulation causes powder particles to agglomerate in order to improve flow and compression characteristics.
• Drying removes moisture from solid materials.
• Coating applies a film to the surface of tablets or granules.
• Compression forms tablets by applying pressure to a powder or granular mixture.
• Filling dispenses a precise amount of a liquid or powder into a container.
• Sterilization eliminates microorganisms from a product or container.

Stability

• Pharmaceutical stability is the extent to which a product maintains its original properties within defined limits during its storage and use.
• Chemical stability refers to the degradation of the drug substance.
• Physical stability involves changes in physical properties like appearance, hardness, and dissolution rate.
• Microbiological stability involves the growth of microorganisms in the product.
• Therapeutic stability is a change in the therapeutic effect.
• Toxicological stability is any significant increase in the drug's toxicity.

Biopharmaceutics

• Biopharmaceutics studies the relationship between the drug's physical/chemical properties, dosage form, and administration route, and how they affect the rate and extent of systemic drug absorption.
• Absorption refers to the process by which a drug enters the bloodstream.
• Distribution refers to the process by which a drug spreads throughout the body.
• Metabolism refers to the process by which the body chemically modifies a drug.
• Excretion refers to the process by which the body eliminates a drug.

Pharmacokinetics

• Pharmacokinetics (PK) studies the time course of drug absorption, distribution, metabolism, and excretion (ADME).
• Bioavailability is the fraction of an administered drug dose that reaches systemic circulation.
• Volume of distribution measures the apparent space in the body available to contain the drug.
• Clearance measures the rate at which the drug is removed from the body.
• Half-life is the time required for the plasma concentration of a drug to decrease by half.

Regulatory Considerations

• Pharmaceutical products are subject to strict regulations to ensure their safety, efficacy, and quality.
• The Food and Drug Administration (FDA) is a regulatory agency in the United States.
• The European Medicines Agency (EMA) is a regulatory agency in Europe.
• Good Manufacturing Practices (GMP) are guidelines ensuring that pharmaceutical products are consistently produced and controlled according to quality standards.
• A New Drug Application (NDA) is submitted to the FDA to request marketing approval for a new drug product.
• An Abbreviated New Drug Application (ANDA) is submitted to the FDA for approval of a generic drug product.