Pharmaceutics Exam 3 + Cumulative Stuff

1. Define pharmaceutics and its importance in pharmaceutical sciences.

Pharmaceutics is the science of designing, developing, and formulating drugs into dosage forms that are safe, effective, and convenient for patient use. It bridges the gap between drug discovery and drug delivery to patients.

Importance:

• Ensures proper drug formulation for desired therapeutic effects.

• Improves drug bioavailability, stability, and patient compliance.

• Addresses issues like solubility, dosage, and delivery routes.

2. Explain the pharmaceutical formulation process and how it differs from compounding.

Formulation Process:

• Involves designing a drug product with active pharmaceutical ingredients (APIs) and excipients to ensure stability, efficacy, and patient acceptability.

• Steps include preformulation, dosage form design, stability testing, and quality control.

Compounding:

• The preparation of individualized medications tailored to specific patient needs.

• Often done in pharmacies, whereas formulation occurs at a manufacturing scale.

Key Difference:

• Formulation: Large-scale, standardized for commercial use.

• Compounding: Small-scale, patient-specific.

3. Stages of Drug Development and FDA Approval

1. Preclinical Studies:

   • Laboratory and animal testing to assess safety and efficacy.

2. Investigational New Drug (IND) Application:

   • Submitted to the FDA to begin clinical trials.

3. Clinical Trials:

   • Phase 1: Safety and dosage testing on healthy volunteers.

   • Phase 2: Efficacy and side effects testing on a small patient group.

   • Phase 3: Large-scale testing for effectiveness and monitoring adverse reactions.

4. New Drug Application (NDA):

   • Comprehensive submission to the FDA for approval to market the drug.

5. Post-Marketing Surveillance (Phase 4):

   • Monitoring the drug's safety and effectiveness in real-world use.

4. Importance of Pharmaceutics in New Drug Development

• Ensures drugs are formulated for optimal absorption, distribution, metabolism, and excretion (ADME).

• Overcomes challenges like poor solubility or stability of APIs.

• Enhances patient adherence through innovative dosage forms.

5. Purpose of the United States Pharmacopeia (USP) and National Formulary (NF)

• USP: Sets standards for the quality, purity, strength, and consistency of medicines, food ingredients, and dietary supplements.

• NF: Focuses on excipients and inactive ingredients.

• Together, they ensure drug safety, efficacy, and compliance with regulatory requirements.

6. Composition of a Typical Drug Monograph

• Name: Official drug name.

• Description: Physical and chemical properties.

• Identification Tests: Methods to confirm drug identity.

• Assay: Quantitative measurement of API.

• Impurities: Permissible levels of contaminants.

• Storage Conditions: Guidelines for stability.

• Dosage Forms: Approved preparations.

7. Compare and Contrast USP <797> and <795> Chapters

• <797>: Standards for sterile compounding (e.g., injections).

  • Focuses on preventing contamination and ensuring sterility.

• <795>: Standards for non-sterile compounding (e.g., capsules, creams).

  • Covers stability, potency, and preparation hygiene.

8. Reasons for Incorporation of Drugs into Various Dosage Forms

1. Improve stability (e.g., converting liquids into solid forms).

2. Enhance bioavailability (e.g., nanoparticles for poorly soluble drugs).

3. Ensure controlled release (e.g., sustained-release tablets).

4. Improve patient compliance (e.g., chewable tablets for children).

9. Principles of Dosage Form Design

1. Safety: Minimize toxicity and side effects.

2. Efficacy: Ensure therapeutic effect.

3. Stability: Maintain drug potency over time.

4. Acceptability: Enhance patient compliance.

5. Convenience: Simplify administration.

10. Importance of Pre-Formulation Studies

• Physical Properties: Particle size, crystallinity, and melting point.

• Chemical Properties: Solubility, pH stability, and compatibility with excipients.

• Biopharmaceutical Properties: Permeability and absorption.

11. Consideration of the Route of Administration

• Determines dosage form (e.g., oral tablets for systemic effects, topical creams for local effects).

• Impacts formulation requirements (e.g., sterility for injections).

12. Principal Objective of Dosage Form Design

• To ensure the safe, effective, and consistent delivery of the active ingredient to achieve the desired therapeutic outcome.

13. Properties of a Drug in Dosage Form Design

1. Solubility: Affects bioavailability.

2. Stability: Resistance to degradation.

3. Permeability: Ability to cross biological membranes.

4. Particle Size: Influences dissolution rate.

5. Taste/Odor: Impacts patient compliance.

14. Five Qualities of an Ideal Dosage Form

1. Efficacy: Delivers the intended therapeutic effect.

2. Safety: Minimal side effects.

3. Stability: Maintains effectiveness over its shelf life.

4. Convenience: Easy to use/administer.

5. Cost-effectiveness: Affordable and accessible.

15. Define Excipients and Their Importance

• Excipients: Inactive substances used in formulations to support drug delivery.

• Importance:

  • Improve stability, taste, and solubility.

  • Facilitate manufacturing (e.g., flow agents).

  • Enhance patient experience (e.g., sweeteners).

16. Reference Book for Excipients

• Handbook of Pharmaceutical Excipients:

  • Details on physicochemical properties, compatibility, and safety.

17. Properties of Excipients

1. Physical: Particle size, density, hygroscopicity.

2. Chemical: Stability, pH, reactivity.

3. Functional: Binding, disintegration, taste masking.

18. Functions of Excipients

• Binders: Help tablets stay intact (e.g., microcrystalline cellulose).

• Disintegrants: Facilitate breakdown in the GI tract (e.g., starch).

• Preservatives: Prevent microbial growth (e.g., parabens).

19. Safety Issues with Excipients

• Allergic reactions (e.g., lactose in intolerant patients).

• Toxicity at high doses (e.g., polyethylene glycol).

20. Flavoring, Sweetening, and Coloring

• Improves patient compliance, especially for pediatric populations.

• Sweeteners: Sucrose, aspartame.

• Colorants: Natural (caramel) vs. synthetic (FD&C dyes).

21. Compare and Contrast Dyes and Lakes

• Dyes:

  • Water-soluble coloring agents.

  • Used in solutions and syrups.

  • Examples: FD&C Blue No. 1, Red No. 40.

• Lakes:

  • Insoluble pigments created by adsorbing dyes onto substrates (e.g., aluminum salts).

  • Used in tablets, capsules, and coatings.

  • More stable than dyes in light and heat.

22. Levels of Flavors and Colorants in Pharmaceuticals

• Flavors: Typically used at 0.1% to 1% of the formulation.

• Colorants: Typically used at 0.001% to 0.01%, depending on the dosage form.

23. Four Key Processes of Pharmacokinetics (ADME)

1. Absorption: Drug enters systemic circulation.

2. Distribution: Drug disperses into tissues and organs.

3. Metabolism: Drug undergoes biochemical modification (primarily in the liver).

4. Excretion: Drug and metabolites are eliminated (via kidneys, bile, etc.).

Importance: Determines the drug's bioavailability, efficacy, and dosing frequency.

24. Chemical Bonding Fundamentals

• Covalent Bonds: Strong, stable bonds formed by sharing electrons.

• Ionic Bonds: Attraction between oppositely charged ions.

• Hydrogen Bonds: Weak interactions involving hydrogen and electronegative atoms.

25. Intermolecular vs. Intramolecular Forces

• Intermolecular Forces:

  • Between molecules (e.g., van der Waals, hydrogen bonding).

  • Influence solubility, boiling points, and drug-receptor interactions.

• Intramolecular Forces:

  • Within a molecule (e.g., covalent and ionic bonds).

  • Determine molecular structure and stability.

26. Dipoles and Intermolecular Bonds

• A dipole is a separation of charges within a molecule due to differences in electronegativity.

• Dipoles contribute to intermolecular bonds such as hydrogen bonding and dipole-dipole interactions, affecting solubility and drug interactions.

27. Types of Attractive Forces

1. Van der Waals Forces: Weak interactions.

2. Dipole-Dipole Interactions: Between polar molecules.

3. Hydrogen Bonds: Strong dipole interactions involving hydrogen.

4. Ionic Bonds: Between charged particles.

28. Repulsive Forces and Molecular Distance

• As molecules come closer, repulsive forces (due to electron cloud overlap) increase.

• Equilibrium between attractive and repulsive forces determines molecular stability.

29. States of Matter

1. Solid: Fixed shape and volume (e.g., crystalline or amorphous drugs).

2. Liquid: Fixed volume but variable shape (e.g., suspensions).

3. Gas: Neither fixed shape nor volume (e.g., inhalers).

30. Advantages of Solid Dosage Forms

1. Stability: Less prone to degradation.

2. Convenience: Portable and easy to store.

3. Controlled Release: Modifications for extended-release formulations.

4. Cost-Effective: Easier to manufacture in bulk.

31. Amorphous vs. Crystalline Solids

• Amorphous Solids:

  • Disordered arrangement of molecules.

  • Higher solubility but less stable.

• Crystalline Solids:

  • Ordered molecular structure.

  • More stable but lower solubility.

32. Melting Point and Heat of Fusion

• Melting Point: Temperature at which a solid becomes a liquid.

  • Indicator of drug purity.

• Heat of Fusion: Energy required to melt a solid.

  • Affects drug processing and stability.

33. Polymorphism

• The existence of a substance in multiple crystalline forms.

• Different forms have varying solubility, stability, and bioavailability.

34. Solvates

• Crystals that incorporate solvent molecules into their structure.

• Challenges: Reduced stability and altered dissolution rates.

35. Cocrystals

• Crystals formed by combining the API with a co-former.

• Roles:

  • Enhance solubility, stability, and bioavailability.

36. Particle Sizes for Various Dosage Forms

• Tablets: 50–500 µm.

• Inhalation Powders: 1–5 µm.

• Suspensions: 10–50 µm.

37. Advantages of Particle Size Reduction

1. Improves dissolution and bioavailability.

2. Enhances uniformity in mixing.

3. Increases stability by reducing sedimentation.

38. Definitions

• Solution: Homogeneous mixture of solute and solvent.

• Solubility: Maximum amount of solute dissolved in a solvent.

• Saturated Solution: Solvent holds the maximum solute.

• Supersaturated Solution: Solvent holds more solute than its saturation point.

39. Importance of Water Solubility for APIs

• Affects absorption, bioavailability, and therapeutic efficacy.

40. USP Solubility Expressions

• Soluble: 1–10 parts solvent for 1 part solute.

• Sparingly Soluble: 30–100 parts solvent for 1 part solute.

41. Noyes-Whitney Dissolution Model

• Describes dissolution rate: Rate=DA(Cs−C)h\text{Rate} = \frac{DA (C_s - C)}{h}Rate=hDA(Cs​−C)​

  • DDD: Diffusion coefficient.

  • AAA: Surface area.

  • CsC_sCs​: Saturation concentration.

  • hhh: Thickness of diffusion layer.

42. Factors Affecting Dissolution Rate

1. Particle size (smaller is faster).

2. Temperature (higher increases rate).

3. Solvent viscosity (lower viscosity enhances rate).

43. Tablet Dissolution Process

1. Disintegration into smaller particles.

2. Dissolution of particles.

3. Absorption into systemic circulation.

44. Particle Size and Dissolution Rate

• Smaller particles → Larger surface area → Faster dissolution.

45. Lowry-Bronsted Definition of Acids/Bases

• Acid: A substance that donates a proton (H⁺).

• Base: A substance that accepts a proton (H⁺).

46. Ionization of Strong Acids vs. Weak Acids

• Strong Acids:

  • Fully ionized in aqueous solution.

  • Example: HCl.

• Weak Acids:

  • Partially ionized in aqueous solution.

  • Example: Acetic acid (CH3COOHCH_3COOHCH3​COOH).

47. Degree of Ionization of Acid and Base Drugs

• Acid Drugs: Ionization increases as pH rises above their pKa.

• Base Drugs: Ionization increases as pH decreases below their pKa.

48. Various Charges on Acids and Bases

• Acids: Neutral (unionized) or negatively charged (ionized).

• Bases: Neutral (unionized) or positively charged (ionized).

49. Conjugate Acid-Base Pair Concept

• A conjugate pair consists of an acid and its corresponding base, differing by one proton.

  • Example: NH3/NH4+NH_3/NH_4^+NH3​/NH4+​.

50. Effect of pH on Ionization

• Acids: Ionization increases in basic environments (higher pH).

• Bases: Ionization increases in acidic environments (lower pH).

51. Henderson-Hasselbalch Equation for Degree of Ionization

• For acids: pH=pKa+log⁡[A−][HA]pH = pKa + \log \frac{[A^-]}{[HA]}pH=pKa+log[HA][A−]​

• For bases: pH=pKa+log⁡[B][BH+]pH = pKa + \log \frac{[B]}{[BH^+]}pH=pKa+log[BH+][B]​

52. Ionization Curves of Acids and Bases

• Acids: Gradual increase in ionization as pH exceeds pKa.

• Bases: Gradual decrease in ionization as pH exceeds pKa.

53. Importance of Ionization in ADME and Formulation

• Affects:

  • Absorption: Unionized forms cross membranes more readily.

  • Distribution: Ionized forms may localize in aqueous environments.

  • Excretion: Ionized forms are excreted more efficiently.

54. Ionization of Amphoteric Drugs

• Contain both acidic and basic groups.

• Example: Amino acids (can act as acid or base depending on pH).

55. Salt Formation for Acidic and Basic Drugs

• Acids: React with bases to form salts (e.g., sodium acetate).

• Bases: React with acids to form salts (e.g., hydrochloride salts).

56. Identifying Acidic and Basic Salts by Names

• Acidic Salts: Sodium acetate, potassium citrate.

• Basic Salts: Ammonium chloride, calcium gluconate.

57. Advantages of Salt Formation

1. Improves solubility.

2. Enhances stability.

3. Aids in better absorption.

4. Simplifies manufacturing.

58. Varying Properties of Salt Forms

• Different salts can have unique solubility, dissolution, and stability profiles, affecting bioavailability.

59. Definition of Buffers and Buffered Solutions

• Buffer: A solution that resists pH changes when small amounts of acid or base are added.

• Components: A weak acid and its conjugate base (or vice versa).

60. Preparation of Acidic and Basic Buffers

• Acidic Buffer: Mixture of a weak acid (e.g., acetic acid) and its salt (e.g., sodium acetate).

• Basic Buffer: Mixture of a weak base (e.g., ammonia) and its salt (e.g., ammonium chloride).

61. Mechanism of Buffer Action

• Buffers neutralize added H⁺ or OH⁻ to maintain pH by shifting equilibrium:

  • HA↔H++A−HA \leftrightarrow H^+ + A^-HA↔H++A− (acid buffer).

  • B+H+↔BH+B + H^+ \leftrightarrow BH^+B+H+↔BH+ (basic buffer).

62. Henderson-Hasselbalch Equation for Buffer pH

• pH=pKa+log⁡[Salt][Acid] pH = pKa + \log \frac{[Salt]}{[Acid]}pH=pKa+log[Acid][Salt]​

63. Applications of Buffers in Pharmaceutical Sciences

1. Maintain stability of formulations.

2. Optimize drug solubility.

3. Enhance patient comfort (e.g., pH-adjusted ophthalmic solutions).

64. Five Forms of Drug Stability

1. Physical: Appearance, dissolution.

2. Chemical: API degradation.

3. Microbial: Growth prevention.

4. Therapeutic: Maintenance of efficacy.

5. Toxicological: Avoiding formation of harmful degradation products.

65. Major Types of Chemical Instability

1. Hydrolysis.

2. Oxidation.

3. Photolysis.

4. Racemization.

66. Hydrolysis Mechanism

• Involves cleavage of chemical bonds by water.

  • Example: Ester bonds breaking to form alcohol and acid.

67. Functional Groups Susceptible to Hydrolysis

• Esters, amides, lactones, and lactams.

68. Strategies to Minimize Hydrolysis

1. Use of desiccants.

2. Formulation at optimal pH.

3. Use of non-aqueous solvents.

69. Drug Oxidation Mechanism

• Involves the loss of electrons (e.g., Fe2+→Fe3+Fe^{2+} \to Fe^{3+}Fe2+→Fe3+).

• Initiators: Oxygen, light, metal ions.

70. Strategies to Control Oxidation

1. Use of antioxidants (e.g., ascorbic acid).

2. Packaging in oxygen-impermeable containers.

3. Storage in low-temperature conditions.

71. Photolysis and Minimization

• Photolysis: Degradation due to light exposure.

  • Minimized by:

    • Using amber glass containers.

    • Incorporating UV blockers.

72. Examples of Microbial Preservatives

• Parabens, benzalkonium chloride, sorbic acid.

73. Shelf Life and Expiration Date

• Shelf Life: Time during which a drug maintains potency within acceptable limits.

• Expiration Date: End of the drug’s shelf life.

74. Order of Chemical Reaction

• Zero-Order: Constant rate, independent of concentration.

• First-Order: Rate depends on concentration.

75. Calculations for Zero and First Order Kinetics

• Zero-Order: C=C0−ktC = C_0 - ktC=C0​−kt

  • t1/2=C02kt_{1/2} = \frac{C_0}{2k}t1/2​=2kC0​​.

• First-Order: C=C0e−ktC = C_0 e^{-kt}C=C0​e−kt

  • t1/2=0.693kt_{1/2} = \frac{0.693}{k}t1/2​=k0.693​.

76. Zero-Order Kinetics in Suspensions

• Occurs because the drug concentration in solution is replenished by solid dissolution, maintaining a constant rate.

77. Shelf Life for Zero and First Order Kinetics

• Zero-Order: t90=0.1C0kt_{90} = \frac{0.1C_0}{k}t90​=k0.1C0​​

• First-Order: t90=0.105kt_{90} = \frac{0.105}{k}t90​=k0.105​

78. Identify Dosage Forms Associated with a Particular Route of Administration

1. Oral:

   • Tablets, capsules, syrups, solutions, suspensions.

2. Parenteral:

   • Intravenous (IV): Solutions, emulsions.

   • Intramuscular (IM) and Subcutaneous (SC): Solutions, suspensions.

3. Topical:

   • Creams, ointments, gels, patches.

4. Inhalation:

   • Aerosols, dry powder inhalers (DPIs), nebulizers.

5. Rectal/Vaginal:

   • Suppositories, creams, foams.

6. Ophthalmic/Otic:

   • Drops, ointments.

79. Associate the Steps of ADME with a Blood Plasma Concentration-Time Curve

1. Absorption:

   • Initial rise in plasma concentration until CmaxC_{max}Cmax​.

2. Distribution:

   • Plateau or slight decline as drug disperses into tissues.

3. Metabolism:

   • Decline in concentration due to liver enzyme activity.

4. Excretion:

   • Terminal phase as drug is eliminated.

80. Key Data Points in Blood Plasma Concentration-Time Curve Following Oral Administration

1. Lag Time:

   • Time before drug appears in plasma.

2. CmaxC_{max}Cmax​:

   • Peak plasma concentration.

3. TmaxT_{max}Tmax​:

   • Time to reach CmaxC_{max}Cmax​.

4. AUC (Area Under Curve):

   • Represents total drug exposure.

5. Elimination Phase:

   • Declining curve indicates metabolism and excretion.

81. Differentiate Between Biopharmaceutics, Bioavailability, and Bioequivalence

1. Biopharmaceutics:

   • Studies the effects of formulation and physiologic factors on ADME.

2. Bioavailability:

   • Fraction of administered drug reaching systemic circulation.

3. Bioequivalence:

   • Comparison of bioavailability between two formulations.

82. Impact of Formulation on Absorption Rate

1. Excipients like disintegrants enhance dissolution.

2. Modified-release formulations control TmaxT_{max}Tmax​ and CmaxC_{max}Cmax​.

3. Particle size reduction increases surface area for faster absorption.

83. Connection Between Absorption and First-Pass Effect

• Drugs absorbed via the GI tract pass through the liver via the portal vein.

• Extensive liver metabolism reduces systemic bioavailability.

84. Concentration Gradients and Time

• Drug diffusion rate is proportional to the concentration gradient.

• Over time, as equilibrium is reached, the gradient and diffusion slow down.

85. One-Compartment Pharmacokinetic Model Assumptions

1. The body acts as a single, uniform compartment.

2. Drug distribution is instantaneous.

3. Elimination follows first-order kinetics.

86. Common Algebraic Forms in Pharmacokinetics

1. Zero-Order Kinetics: C=C0−ktC = C_0 - ktC=C0​−kt

2. First-Order Kinetics: C=C0e−ktC = C_0 e^{-kt}C=C0​e−kt

87. Relationships Between Pharmacokinetic Parameters

1. Clearance (CLCLCL) affects half-life (t1/2t_{1/2}t1/2​).

   • t1/2∝VdCLt_{1/2} \propto \frac{V_d}{CL}t1/2​∝CLVd​​.

2. Volume of Distribution (VdV_dVd​) affects drug tissue penetration.

88. Interpreting Data and Graphs to Calculate Pharmacokinetic Parameters

1. AUC:

   • Measured using the trapezoidal rule.

2. Elimination Rate Constant (kek_eke​):

   • Slope of the log-linear elimination phase.

3. Clearance: CL=DoseAUCCL = \frac{\text{Dose}}{\text{AUC}}CL=AUCDose​

89. Clearance

• Volume of plasma cleared of drug per unit time.

• Includes renal, hepatic, and other pathways.

90. Relationships Between Clearance and Other Parameters

• CL∝ke×VdCL \propto k_e \times V_dCL∝ke​×Vd​.

• Higher CLCLCL leads to faster elimination.

91. Predicting Half-Life Changes

• Increased clearance (CLCLCL) reduces half-life.

• Increased VdV_dVd​ prolongs half-life.

92. Factors a Pharmacist Must Consider for Dosage Regimen

1. Patient Factors:

   • Age, weight, kidney/liver function.

2. Drug Properties:

   • Half-life, therapeutic index.

3. Clinical Goals:

   • Maintain therapeutic plasma levels.

93. Q10 Method for Shelf Life Determination

• Predicts the change in degradation rate with temperature. Q10=(k2k1)10T2−T1Q_{10} = \left( \frac{k_2}{k_1} \right)^{\frac{10}{T_2 - T_1}}Q10​=(k1​k2​​)T2​−T1​10​

• Typical Q10Q_{10}Q10​: 2–3.

94. Drug Stability Testing Process

1. Real-Time Testing:

   • Storage at recommended conditions.

2. Accelerated Testing:

   • High temperature/humidity to predict long-term stability.

95. Estimation of Shelf Life Using Q10

• Shelf life ratio: tnew=told/Q10ΔT10t_{\text{new}} = t_{\text{old}} / Q_{10}^{\frac{\Delta T}{10}}tnew​=told​/Q1010ΔT​​

96. Stability Testing Protocols

• Conducted at various intervals (e.g., 6, 12, 24 months).

• Assesses:

  • Physical stability (appearance, dissolution).

  • Chemical stability (API integrity).

97. Types of Containers by Material

1. Glass:

   • Type I (borosilicate) for injectables.

   • Type III (soda lime) for oral liquids.

2. Plastic:

   • Lightweight but may allow permeability.

3. Metal:

   • Used for aerosols.

98. Single vs. Multiple Dose Containers

• Single-Dose:

  • No preservatives; one-time use.

• Multiple-Dose:

  • Contains preservatives; reusable.

99. Well-Closed vs. Tight-Closed Containers

• Well-Closed:

  • Protects from contamination.

• Tight-Closed:

  • Prevents entry of air or moisture.

100. Sorption and Leaching

• Sorption: Adsorption or absorption of drug into the container material.

• Leaching: Migration of container components into the drug formulation.

101. Closure and Child-Resistance Packaging

• Ensures safety by preventing access to hazardous substances by children while remaining user-friendly.

102. Importance of Biotechnology in Pharmaceutical Sciences

• Enables production of biologics (e.g., insulin, monoclonal antibodies).

• Facilitates development of personalized therapies.

103. Small Molecule vs. Biotech Drugs

1. Small Molecule:

   • Low molecular weight.

   • Chemically synthesized (e.g., aspirin).

2. Biotech Drugs:

   • Large, complex molecules.

   • Produced using living systems (e.g., monoclonal antibodies).

104. Examples of Biotech Products

1. Recombinant insulin.

2. Monoclonal antibodies (e.g., adalimumab).

3. Vaccines (e.g., mRNA-based COVID-19 vaccines).

105. DNA and RNA Structures

• DNA:

  • Double-stranded helix.

  • Bases: A, T, G, C.

• RNA:

  • Single-stranded.

  • Bases: A, U, G, C.

106. Central Dogma

• Describes the flow of genetic information: DNA→RNA→Protein\text{DNA} \to \text{RNA} \to \text{Protein}DNA→RNA→Protein

107. Procedures and Enzymes in Recombinant DNA Technology

1. Procedures:

   • Isolation of DNA.

   • Cutting DNA using restriction enzymes.

   • Insertion into vectors (e.g., plasmids).

   • Transformation into host cells (e.g., E. coli).

   • Selection of transformed cells.

   • Amplification and expression of desired proteins.

2. Key Enzymes:

   • Restriction Endonucleases: Cut DNA at specific sequences.

   • Ligases: Join DNA fragments.

   • Polymerases: Amplify DNA during PCR.

108. Difference Between Antigen and Epitope

• Antigen:

  • Any molecule capable of inducing an immune response.

  • Examples: Proteins, polysaccharides, lipids.

• Epitope:

  • The specific region on an antigen recognized by antibodies or T-cell receptors.

109. Structure and Components of an Antibody

• Structure:

  • Y-shaped glycoprotein.

  • Two heavy chains and two light chains.

• Components:

  • Fab Region: Antigen-binding site (variable region).

  • Fc Region: Constant region; mediates immune responses.

110. Antibody Production Process

1. Immunization of animals with the antigen.

2. Collection of spleen cells producing antibodies.

3. Fusion of spleen cells with myeloma cells to create hybridomas.

4. Selection and cloning of hybridomas producing desired antibodies.

5. Purification of antibodies.

111. Polyclonal vs. Monoclonal Antibodies

• Polyclonal:

  • Mixture of antibodies targeting multiple epitopes on an antigen.

  • Produced by multiple B-cell clones.

• Monoclonal:

  • Single type of antibody targeting one epitope.

  • Produced by a single B-cell clone.

112. Challenges in Protein Drug Development

1. Poor stability (susceptible to denaturation and degradation).

2. High production costs.

3. Limited oral bioavailability due to enzymatic degradation in the GI tract.

113. Types of Instabilities in Protein Drugs

1. Physical: Aggregation, denaturation.

2. Chemical: Deamidation, oxidation, hydrolysis.

114. Reasons for Protein Drug Instability

• Sensitive to temperature, pH, and enzymatic degradation.

• Tertiary structure disruption affects functionality.

115. Spray Drying Process

• A solution or suspension is sprayed into a hot drying chamber.

• The solvent evaporates, leaving behind fine dry particles.

• Used for producing inhalable powders or stabilized formulations.

116. Freeze-Drying Process (Lyophilization)

1. Freezing the solution containing the drug.

2. Sublimation of ice under vacuum.

3. Desorption of bound water to obtain a stable dry product.

117. Importance of Lyophilization in Protein Drug Formulation

• Enhances stability by removing water, which reduces degradation.

• Facilitates storage and transport at room temperature.

118. Sterilization of Biotech Products

1. Filtration: For heat-sensitive proteins.

2. Autoclaving: For heat-stable components.

3. Gamma Radiation: For packaging and surfaces.

119. Proteins and Oral Administration

• Cannot be administered orally due to:

  • Enzymatic degradation in the GI tract.

  • Poor permeability through intestinal membranes.

120. Use of Antibodies for Targeted Delivery Systems

• Antibodies are engineered to target specific cells or receptors, delivering drugs directly to diseased tissues while sparing healthy ones.

121. Antibody-Drug Conjugates (ADCs)

• Composed of:

  • Antibody: Targets specific antigens.

  • Drug: Cytotoxic agent.

  • Linker: Connects the drug to the antibody and ensures stability until reaching the target.

122. Virus-Based vs. mRNA-Based Vaccines

• Virus-Based:

  • Use inactivated or attenuated viruses to elicit immune response.

  • Examples: Influenza, polio vaccines.

• mRNA-Based:

  • Use mRNA coding for viral proteins.

  • Examples: COVID-19 mRNA vaccines.

123. Basic Concepts of Polymers

• Definition: Large molecules formed by repeating units (monomers).

• Classifications:

  • Natural (e.g., collagen).

  • Synthetic (e.g., polyethylene glycol).

124. Degree of Polymerization (DP)

• Number of monomer units in a polymer chain.

  • DP=Molecular Weight of PolymerMolecular Weight of Monomer\text{DP} = \frac{\text{Molecular Weight of Polymer}}{\text{Molecular Weight of Monomer}}DP=Molecular Weight of MonomerMolecular Weight of Polymer​.

125. Applications of Polymers in Pharmaceutical Sciences

1. Controlled-release drug delivery.

2. Bioadhesive systems.

3. Stabilizers in formulations.

126. Pharmaceutical Nanotechnology

• Application of nanotechnology for drug delivery and diagnostics.

• Focuses on designing nanoparticles for improved drug targeting and efficacy.

127. Nano-Based Drug Delivery Systems

1. Liposomes: Vesicles with lipid bilayers.

2. Nanoparticles: Solid colloidal particles.

3. Micelles: Aggregates of surfactant molecules.

128. Advantages of Nano-Based Delivery Systems

1. Enhanced drug solubility.

2. Targeted drug delivery.

3. Reduced side effects.

129. Phospholipids and Liposomes

• Phospholipids: Amphiphilic molecules with hydrophilic heads and hydrophobic tails.

• Liposomes: Spherical vesicles formed by phospholipid bilayers, used for drug delivery.

130. Advantages of Liposome Formulation

1. Biocompatibility and biodegradability.

2. Protection of drugs from degradation.

3. Controlled release.

131. Enhanced Permeation and Retention (EPR) Effect

• Exploited in tumor targeting, where nanoparticles accumulate due to leaky vasculature and poor lymphatic drainage.

132. Preparation of Liposomes

1. Hydration of lipid films.

2. Sonication or extrusion for size reduction.

3. Loading of drugs.

133. Types of Liposomes

1. Conventional: Basic phospholipid vesicles.

2. Stealth: PEG-coated for prolonged circulation.

3. Immunoliposomes: Functionalized with antibodies for targeted delivery.

134. Properties of Stealth Liposomes

• PEGylation reduces immune recognition, increasing circulation time.

135. Immunoliposomes in Drug Delivery

• Antibody-functionalized liposomes target specific antigens for precise delivery.

136. Polymeric vs. Lipid Micelle Systems

• Polymeric Micelles:

  • Formed by block copolymers.

  • Stable in aqueous environments.

• Lipid Micelles:

  • Composed of phospholipids.

  • Less stable than polymeric systems.

137. Construction of Dendrimers

• Highly branched, tree-like macromolecules with a central core.

• Multiple functional groups for drug conjugation.

138. Applications of Dendrimers in Drug Delivery

1. Targeted drug delivery.

2. Gene therapy.

3. Solubilization of poorly soluble drugs.

139. Types of Solid Nanoparticles

1. Nanospheres: Solid matrix systems.

2. Nanocapsules: Drug enclosed within a shell.

140. Nanospheres vs. Nanocapsules

• Nanospheres:

  • Matrix-type particles where drug is dispersed throughout.

• Nanocapsules:

  • Core-shell structure where drug is confined in the core.