Pharmaceutical Chemistry Concepts

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Questions and Answers

Which of the following best describes transesterification?

A reaction where esters are hydrolyzed into carboxylic acids

A reaction where esters are converted into amides

A method to synthesize phenothiazines from polyunsaturated fatty acids

A process that involves heating esters with an alcohol and an acid catalyst (correct)

What is a common method for mediating oxidation in drug compounds?

Heating with an amine

Utilizing UV light exposure

Reacting with atmospheric oxygen (correct)

Mixing with hydrolysates of esters

Which of the following drugs is known to be susceptible to photolysis?

Sodium bisulfite

Butylated hydroxytoluene

Hydrocortisone (correct)

Simvastatin

What is the primary function of commonly used antioxidants like ascorbic acid?

To protect drugs from degradation by oxidation Signup and view all the answers

What method can be employed to protect drug molecules from degradation due to light exposure?

Coating tablets with polymer film containing UV absorbers Signup and view all the answers

What does the half-life ($t_{1/2}$) of a first-order reaction indicate?

The time it takes for the concentration to halve Signup and view all the answers

In the context of drug stability, what does shelf life refer to?

The period during which a drug remains stable with NLT 90% potency Signup and view all the answers

Which statement best defines zero-order kinetics?

The reaction rate is constant regardless of the concentration of the reactant Signup and view all the answers

What is indicated by the correlation coefficient value of 0.846?

A strong positive correlation Signup and view all the answers

What is the purpose of using a non-parametric procedure like Spearman's rank correlation?

To analyze ordinal or ranked data effectively Signup and view all the answers

What does the term 'clearance' (Cl) measure in pharmacokinetics?

The amount of drug removed from the body in a specific time Signup and view all the answers

Which of the following is NOT a factor influencing the rate of reactions in chemical kinetics?

Type of container used Signup and view all the answers

What is the recommended stability testing frequency for a pharmaceutical product after the second year of study?

Once every year Signup and view all the answers

What is the significance of an expiration date on a drug preparation?

It dictates when a drug may lose its labeled potency Signup and view all the answers

Which storage temperature falls under the category of 'Warm'?

30-40°C (86-104°F) Signup and view all the answers

Which of the following factors does NOT affect the stability of a pharmaceutical product?

Branding design Signup and view all the answers

What type of stability is primarily concerned with the appearance of a pharmaceutical product?

Physical stability Signup and view all the answers

Which of the following is a common catalyst for hydrolytic degradation of drugs?

H+ ions Signup and view all the answers

Which type of incompatibility may lead to physical changes in the organoleptic properties of a drug?

Physical incompatibility Signup and view all the answers

What degradation process are drugs containing ester, amide, lactam, imide or carbamate groups most susceptible to?

Hydrolysis Signup and view all the answers

What is the significance of uniformity in product stability evaluations?

Ensures proper dosage delivery Signup and view all the answers

What is the effect of excessive heat on drug stability?

Chemical deterioration Signup and view all the answers

Which of the following factors can influence the length of time between handling, manufacture, and usage of a drug?

Transportation methods Signup and view all the answers

What is the primary purpose of dialysis in the context of colloidal particles?

To separate colloidal particles from small molecules Signup and view all the answers

Which of the following best describes a dispersed phase in a colloidal system?

The particles that are distributed within the medium Signup and view all the answers

What pore size characterizes ultrafiltration membranes used in separation processes?

1 nm to 100 nm Signup and view all the answers

In the context of colloidal dispersions, what does the term 'dispersing medium' refer to?

The external continuous phase supporting the dispersed particles Signup and view all the answers

When performing ultrafiltration, what type of pressure is typically applied?

Negative pressure (suction) Signup and view all the answers

Which of the following statements about colloidal particles is true?

Colloidal particles are larger than small molecules and ions. Signup and view all the answers

What is the effect of dialysis on the concentration of low molecular weight substances in the blood?

It reduces their concentration Signup and view all the answers

What defines a colloidal dispersion?

A heterogeneous mixture of dispersed particles in a continuous medium Signup and view all the answers

How do small molecules and ions behave in a dialysis process?

They pass through the dialysis membrane freely Signup and view all the answers

Which process is used to separate and purify colloidal material?

Ultrafiltration Signup and view all the answers

What does accelerated stability studies primarily aim to achieve?

To predict the shelf life of a product quickly Signup and view all the answers

Which of the following factors is NOT monitored during the stability studies for drug products?

Market positioning of the product Signup and view all the answers

What environmental conditions are typically used in long-term stability studies?

25C / 60% RH Signup and view all the answers

Which type of stability testing involves using elevated temperatures in increments?

Stress Tests Signup and view all the answers

What is the minimum duration for long-term stability studies?

2 years Signup and view all the answers

Which climatic zone is characterized by hot and humid conditions?

Zone 4 Signup and view all the answers

What does the retention of physical qualities in cosmetics refer to?

The elegance and appeal of the product Signup and view all the answers

Which aspect is NOT a goal of accelerated stability studies?

Establishing patient dosage levels Signup and view all the answers

What is the common temperature range for conducting accelerated stability studies?

37-40C Signup and view all the answers

In long-term stability studies, which factor does NOT change?

Active ingredient concentration Signup and view all the answers

Study Notes

Colloidal Dispersion

Colloidal dispersions are mixtures with intermediate particle sizes between true solutions and coarse dispersions.
Dispersed particles (internal phase) are discontinuous.
Dispersing medium (external phase) is continuous.
Colloids are categorized as lyophilic (solvent-loving) or lyophobic (solvent-hating).

Classification of Dispersed Systems

True solutions: homogenous mixtures with dissolved components at a molecular level, particle size <1 nm.
Colloidal dispersions: particle size intermediate (1 nm - 0.5µm).
Coarse dispersions: particle size >0.5µm, such as suspensions and emulsions.

Methods for Determining Particle Size

Microscopy: techniques like optical miscroscopy for particle size measurements to 100 micron.
Sieving: uses calibrated sieves to determine particle size based on sieving capacity.
Sedimentation: measurements of the rate of particle settling in appropriate instruments like Andreasen apparatus are methods for determining particle size based on Stokes' Law.
Particle Volume Measurement: using techniques like Coulter counter (resistance changes as particles pass through).

Stability

Stability of a drug is defined as a pharmaceutical formulation in a specific container or closure system remaining with its physical, chemical, and toxicological specifications.
Shelf life is the duration when maintaining the specified potency of the drug.
Important factors that affect stability are storage conditions, temperature, chemical degradation etc
Types of stability include chemical, physical, genotoxic, microbiological, toxicological, and therapeutic stability.

Micromertics & Fundamental and Derived Properties of Particles

Micromertics is the science and technology for determining the properties of small particles.
Micron or Micrometer is unit for particle size expressed as 10⁻⁶m, 10⁻⁴cm, 10⁻³mm.
Fundamental properties include particle size and surface area.
Derived properties include porosity, bulkiness, densities, compressibility, and flow properties.

Important parameters of Drug products

Loss of activity or potency of the active ingredient
Amount of degradation product.
Physical qualities (appearance) of freshly produced products.
Loss of elegance due to instability in the product.

Types of Stability Studies

Short-term/Accelerated Stability Studies: performed under exaggerated conditions of temperature, light, humidity, pH, humidity for a shorter time period.
Long-term/Real Time Stability Studies: determine stability under usual conditions. Assessments of different 'climatic zones' are used.
Stress Tests: use elevated temperatures to observe physical and chemical degradation of products, lasting 6-12 months.

Rheology

Rheology is the study of the deformation and flow of matter.
Types include absolute (poise, centipoise), kinematic (stoke, centistokes), and relative (unitless) units.
Common classifications include Newtonian and Non-Newtonian fluids, with some Non-Newtonian types including plastic (Bingham body), pseudoplastic (shear thinning), dilatant (shear thickening).
Thixotropy and antithixotropy describe fluids recovering from shear thinning.

Methods & Equipment For Measuring Viscosity

Capillary viscometers (Ostwald and Ubbelohde) measure flow rates.
Falling sphere viscometers measure viscosity through a ball's speed fall within a liquid.
Cup and Bob viscometers evaluate resistance of fluids to torque using a rotating bob.
Cone and Plate viscometer measures sample shearing within a narrow gap.

Importance of Rheology in Pharmaceuticals

Formulation of creams, pastes, lotions, emulsions, suspensions, suppositories, and tablet coatings.
Fluidity of injection solutions.
Mixing and flow of materials during packaging.
Physical stability of disperse systems.
Spreading and adherence of quasisolids.
Flow of powders in tabletting or encapsulation.

Product Stability Evaluations

Physical stability: drug's appearance and uniformity over time in the formulation
Chemical stability: drug's chemical composition and potential incompatibilities.
Evaluation tests should include hydrolysis, oxidation, photolysis, isomerization, and polymerization

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Description

Test your knowledge on crucial concepts in pharmaceutical chemistry, including transesterification, oxidation mediation in drug compounds, and the effects of photolysis. This quiz explores the roles of antioxidants and protective methods against light degradation. Challenge yourself and enhance your understanding of drug stability and chemical processes.