DDS-CHAPTER-4

Pharmaceutics

The general area of study concerned with the formulation, manufacture, stability, and effectiveness of pharmaceutical dosage forms.

Dosage form

The physical form in which a drug is administered, such as tablets, capsules, or liquids.

Formulation

The process of designing and creating a dosage form, taking into consideration the physical, chemical, and biologic characteristics of the drug substances and pharmaceutical ingredients.

Stability

The ability of a dosage form to maintain its physical and chemical properties over time, ensuring its effectiveness and safety.

Efficacious

Having the desired therapeutic effect.

Attractive

Appealing in appearance or taste.

QC (Quality Control)

The process of ensuring that a dosage form meets predetermined quality standards.

Fillers or diluents

Inactive substances added to a dosage form to increase its size or volume.

Gastric acid

The acid present in the stomach that can potentially degrade or alter the drug substance.

Orifices

Openings or cavities in the body, such as the mouth, nose, or rectum.

Inhalation therapy

Administering a drug through inhalation, typically for respiratory conditions.

Master formula

A detailed document that provides instructions for the formulation and manufacturing of a dosage form.

Palatability

The taste and overall acceptability of a dosage form.

Preformulation studies

Studies conducted to evaluate the physical and chemical properties of a drug substance before formulating it into a dosage form.

Crystalline structure

The arrangement of molecules in a drug substance, which can impact its stability and solubility.

Melting point

The temperature at which a solid drug substance changes from a solid to a liquid state.

Solubility

The ability of a drug substance to dissolve in a liquid, which can affect its absorption and bioavailability.1. Dosage Form Design:The process of designing the physical form of a pharmaceutical product.

Preformulation Studies

Studies conducted before the formulation of a drug to determine its physical and chemical properties.

Physical Description

The physical characteristics of a dosage form, such as its appearance, texture, and color.

Volatile

Easily evaporating or vaporizing.

Tablet Form

A solid dosage form in the shape of a flat, round or oval disc.

Sublingual Tablet

A tablet that is placed under the tongue and dissolved.

Gel Capsules

Capsules filled with a gelatinous substance.

Solid Ester or Salt Form

A solid form of a drug that is chemically modified to improve its stability or solubility.

Topically

Applied to the surface of the skin.

Microscopic Examination

The examination of a substance under a microscope to observe its particles or crystals.

Heat of Vaporization

The amount of heat required to convert a liquid into a vapor.

Vapor Pressure

The pressure exerted by the vapor of a substance.

Melting Point Depression

The lowering of the melting point of a substance when it is mixed with another substance.

Phase Rule

A rule that describes the number of phases present in a system based on the number of components and degrees of freedom.

Triangular (Three-Component) Phase Diagram

A diagram that shows the phases present in a system with three components.

Particle Size

The size of the particles in a substance, which can affect various properties of the dosage form.1. Dosage Form Design:The process of designing pharmaceutical dosage forms, taking into consideration factors such as particle size, flow characteristics, sedimentation rate, absorption, and solubility.

Preformulation Studies

Studies conducted before the formulation of a drug, which involve evaluating factors such as particle size, polymorphism, solubility, and dissolution rate.

Particle Size

The size of drug particles, which can affect factors such as flow characteristics, sedimentation rate, and dissolution rate.

Flow Characteristics

The ability of drug particles to flow freely, which can affect factors such as manufacturing processes and dosage form performance.

Sedimentation Rate

The rate at which drug particles settle in a liquid, which can affect factors such as dosage form stability and uniformity.

Absorption

The process by which a drug is taken up into the bloodstream, which can be influenced by factors such as particle size, solubility, and dissolution rate.

Polymorphism

The ability of a substance to exist in different crystal forms, which can affect factors such as melting point, solubility, and stability.

Solubility

The ability of a drug to dissolve in a solvent, which can affect factors such as therapeutic efficacy and absorption.

Equilibrium Solubility Method

A method used to determine the solubility of a drug by shaking an excess of drug with a solvent at a constant temperature over a long period of time.

pH Adjustment

The process of adjusting the pH of a solvent to enhance the solubility of a drug, which may be necessary for weak acidic or basic drugs.

Dissolution

The process by which a drug dissolves in a fluid at the absorption site, which can affect factors such as absorption rate and bioavailability.

Constant Surface Method

A method used to measure dissolution rate by eliminating surface area and surface electrical charges as variables.

Particulate Dissolution

A method used to measure dissolution rate by adding a weighed amount of powdered sample to a dissolution medium in a constant agitation system.1. Dosage Form Design:Definition of the process of designing the form in which a pharmaceutical drug will be administered to the patient.

Preformulation Studies

Studies conducted before the formulation of a drug to understand its physical and chemical properties.

Dissolution

The process by which a solid drug substance dissolves in a liquid solvent.

Particulate dissolution

The dissolution of a drug substance in the form of particles, which can be affected by surface charge and agglomeration.

Fick's Laws of Diffusion

Mathematical equations that describe the rate of diffusion of a drug through various barriers in the body.

Noyes-Whitney Equation

An equation used to calculate the rate of dissolution of a drug substance in a solvent.

Membrane Permeability

The ability of a drug molecule to cross a biological membrane.

pH Partition Theory

The theory that explains the relationship between the dissociation constant, lipid solubility, and pH at the absorption site with the absorption characteristics of various drugs.

Partition Coefficient

A measure of a molecule's preference for the hydrophilic or lipophilic phase, indicating its lipophilic character.

pKa/Dissociation Constants

The pKa value represents the pH at which a drug molecule is 50% ionized, and dissociation constants describe the extent of ionization of a drug.

Drug and Drug Product Stability

Evaluation of the physical and chemical stability of a drug substance, including its solid-state stability, solution-phase stability, and stability in the presence of excipients.

Mechanisms of Degradation

Processes such as hydrolysis and oxidation that can lead to the degradation of drugs, resulting in the formation of breakdown products.

Hydrolysis

A solvolysis process in which drug molecules interact with water molecules to yield breakdown products.

Oxidation

The loss of electrons from a molecule, which can lead to the degradation of various types of drugs.

Free Chemical Radicals

Molecules or atoms containing one or more unpaired electrons, such as molecular oxygen and free hydroxyl radicals.1. Autoxidations:Spontaneous reactions that occur under the influence of atmospheric oxygen and can lead to the degradation of drugs.

Chain reaction

A reaction in which oxygen combines with a drug molecule, leading to the destruction of other drug molecules.

Stability

The ability of a drug or drug product to maintain its chemical, physical, microbiologic, therapeutic, and toxicologic properties over time.

Rate reactions

The description of the change in drug concentration with respect to time.

Zero-Order

A reaction in which the loss of drug is independent of the concentration of reactants and constant with respect to time.

First-Order

A reaction in which the loss of drug is directly proportional to the concentration remaining with respect to time.

Half-life

The time required for the concentration of a drug to decrease by half.

Energy of Activation

The energy required to initiate a chemical reaction.

Arrhenius Equation

An equation used to project the stability of a drug over time based on temperature.

Q10 Method of Shelf Life Estimation

A method used by pharmacists to estimate the shelf life of a product under different storage conditions.

Hydrolysis

The chemical breakdown of a drug substance due to reaction with water.

Waterproof protective coating

A coating applied to solid dosage forms to protect against hydrolysis.

Nonaqueous vehicle

A liquid vehicle used to suspend liquid drugs to protect against hydrolysis.

Buffer

A solution that can resist changes in pH and is composed of a weak acid and its conjugate base or a weak base and its conjugate acid.1. Buffers:Solutions prepared by mixing a weak acid and its conjugate base or a weak base and its conjugate acid to maintain a stable pH.

Henderson-Hasselbalch equation

An equation used to calculate the pH of a buffer solution based on the pKa of the weak acid and the ratio of its conjugate base to acid.

Oxidation

The process in which a substance loses electrons, resulting in a chemical reaction that can lead to degradation or alteration of the drug product.

Antioxidants

Substances that prevent or inhibit oxidation by neutralizing free radicals and protecting the drug product from degradation.

Inert gas

A gas, such as nitrogen, that does not react with other substances and is used to replace air in packaging to prevent oxidation of oxygen-sensitive drugs.

Trace metals

Small amounts of metals that can originate from the drug, solvent, container, or stopper and can catalyze oxidation reactions.

Purification

The process of removing impurities, such as trace metals, from labile preparations to enhance stability.

Sodium Sulfite

A compound used as an antioxidant at high pH values to prevent oxidation.

Ascorbic Acid

A vitamin C derivative that acts as an antioxidant to prevent oxidation.

Sulfites

Components that can cause allergic reactions in some individuals, particularly asthmatic patients, and are regulated by the FDA.

Photostability

The ability of a drug product to resist degradation or alteration when exposed to light.

Stability Testing

The process of evaluating the stability of a drug product under various conditions, including temperature, light, and humidity, to ensure its safety and effectiveness throughout its shelf life.

Pharmaceutical Ingredients

The active and inactive components of a drug product that can influence its stability.

Container and Closure

The packaging materials used for a drug product that can affect its stability.

Manufacturing and Processing Conditions

The conditions under which a drug product is manufactured and processed, which can impact its stability.

Packaging Components

The materials used for packaging a drug product, including containers, closures, and labels, which can affect its stability.

Conditions of Storage

The environmental conditions, such as temperature, light, and humidity, in which a drug product is stored, which can impact its stability.

Conditions of Shipping

The conditions, including temperature, light, and humidity, during transportation of a drug product, which can affect its stability.1. Dosage Form Design:The process of designing the physical form of a pharmaceutical product.

Preformulation Studies

Studies conducted before the approval for marketing of a drug product to assess its stability and other formulation considerations.

Stability Testing

Testing conducted to determine the stability of a drug product under various conditions such as temperature, light, and humidity.

Accelerated Stability Studies

Studies conducted to increase the rate of chemical degradation or physical change of a drug substance or product to assess its long-term stability.

Drug Product

The dosage form of a drug in its final immediate packaging intended for marketing.

Drug Substance

The unformulated drug substance that may be formulated with excipients to produce the dosage form.

Excipient

Anything other than the drug substance in the dosage form.

Expiration Date

The approved shelf life specification of a drug product, after which it must not be used.

Shelf Life

The period of time during which a drug product is expected to remain stable and retain its effectiveness.

Stress Testing

Studies undertaken to assess the effect of severe conditions on the stability of a drug substance or product.

Photostability

The ability of a drug substance or product to remain stable when exposed to light.

Appearance and Palatability

The physical appearance and taste of a pharmaceutical preparation.

Flavoring Agent

An ingredient used to mask unwanted taste in a pharmaceutical product.