Advanced Drug Delivery Systems 2
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Questions and Answers

What factor does NOT influence the rate of mass transfer across a polymer?

  • Concentration Gradient
  • Area
  • Permeability
  • Molecular Weight of the Drug (correct)

Which mathematical model describes a constant release rate of a drug?

  • Zero Order Release (correct)
  • Logarithmic Release
  • Square Root of Time Release
  • First Order Release

What happens to the release rate in First Order Release as the amount of drug decreases?

  • It remains constant.
  • It rapidly increases.
  • It becomes erratic.
  • It decreases proportionally to the remaining drug. (correct)

In Square Root of Time Release, how does the release rate decrease over time?

<p>Linear with the square root of time (D)</p> Signup and view all the answers

Which factor will lead to a decreased flux of drug release from a polymer?

<p>Decreased Area (C)</p> Signup and view all the answers

What is the effect of a larger area on the drug release from a polymer?

<p>Faster drug release (A)</p> Signup and view all the answers

Which release model is generally considered not important for controlled release applications?

<p>First Order Release (D)</p> Signup and view all the answers

What characterizes Zero Order Release on a graph of release rate versus time?

<p>A flat line (C)</p> Signup and view all the answers

What is the primary purpose of wax matrix systems in medications like potassium chloride?

<p>To prevent GI irritation by avoiding high local concentrations. (A)</p> Signup and view all the answers

Which of the following is an example of a product that uses the Geomatrix system?

<p>Paxil CR (B)</p> Signup and view all the answers

What characteristic do swelling erodible matrix systems share?

<p>They utilize hydrophilic polymers like HPMC. (D)</p> Signup and view all the answers

How long can the AccuForm system typically retain a dosage form in the stomach?

<p>8-10 hours (C)</p> Signup and view all the answers

Which type of system is characterized by keeping the dosage form in the stomach for an extended period?

<p>Swelling systems (D)</p> Signup and view all the answers

What type of coating is NOT typically involved in coated particle systems?

<p>Completely impermeable covers (A)</p> Signup and view all the answers

What is one example of a medication that utilizes a swelling system?

<p>Metformin GR (B)</p> Signup and view all the answers

Which of the following describes the primary feature of swelling erodible matrix systems?

<p>Both components are bioerodible without leaving residue. (B)</p> Signup and view all the answers

What is the first step in the workflow for developing a biologic drug?

<p>Target identification (D)</p> Signup and view all the answers

Which factor is NOT contributing to the high production cost of biologics?

<p>Rapid manufacturing processes (A)</p> Signup and view all the answers

Which purification method is crucial for ensuring the purity of recombinant proteins?

<p>Quality control (QC) measures (A)</p> Signup and view all the answers

What type of host cells are considered the easiest and cheapest to use in biologic manufacturing?

<p>Bacteria (C)</p> Signup and view all the answers

What characteristic of prodrugs allows them to provide prolonged drug release in depot injections?

<p>They are lipophilic and dissolve slowly. (C)</p> Signup and view all the answers

Which type of antibodies tend to have the lowest immunogenicity and toxicity?

<p>Fully human antibodies (A)</p> Signup and view all the answers

What is a primary concern in mRNA-based antibody therapy?

<p>Stability of the mRNA (A)</p> Signup and view all the answers

Which is an example of a long-acting testosterone prodrug?

<p>Depo-Testosterone (B)</p> Signup and view all the answers

Which phase of clinical trials primarily focuses on safety testing?

<p>Phase 1 (C)</p> Signup and view all the answers

What are the two mechanisms through which bioerodible microspheres release drugs?

<p>Drug diffusion and polymer breakdown (B)</p> Signup and view all the answers

What type of contaminants must be removed during recombinant protein purification?

<p>Cell debris (D)</p> Signup and view all the answers

Which polymer is used in the formulation of Lupron Depot?

<p>Polylactic acid and polyglycolic acid (C)</p> Signup and view all the answers

How does the Atrogel Delivery System facilitate drug release?

<p>By solidifying upon contact with aqueous fluids (C)</p> Signup and view all the answers

Which aspect of Invega Sustenna contributes to its slow dissolution?

<p>It has a long hydrocarbon chain. (B)</p> Signup and view all the answers

What is a unique feature of SUBLOCADE in drug delivery?

<p>It uses a biocompatible solvent for injection. (B)</p> Signup and view all the answers

What is the significance of the lipophilic nature of prodrugs in depot injections?

<p>It enables storage in oily depots and slow release. (C)</p> Signup and view all the answers

What is a significant advantage of mRNA-based therapies over traditional recombinant protein therapies?

<p>Reduced immunogenicity and toxicity (A)</p> Signup and view all the answers

Which step is NOT part of the mechanism by which mRNA therapies work?

<p>The antibody is synthesized in a laboratory (A)</p> Signup and view all the answers

What is a challenge associated with mRNA-based therapies?

<p>Difficulty in expression (A)</p> Signup and view all the answers

Why is the isoelectric point (pI) important for proteins?

<p>It determines protein stability and related properties. (A)</p> Signup and view all the answers

Which statement about mRNA vaccines is correct?

<p>They are designed to carry the genetic blueprint for the spike protein. (B)</p> Signup and view all the answers

Which of the following is a potential benefit of mRNA encoding for personalized therapy?

<p>Flexibility in targeting specific conditions (B)</p> Signup and view all the answers

What is a consequence of the body's cells expressing the spike protein from an mRNA vaccine?

<p>It triggers an immune response providing immunity. (D)</p> Signup and view all the answers

How does the pH affect protein charge relative to its isoelectric point?

<p>At pH above pI, proteins are negatively charged. (C)</p> Signup and view all the answers

What characteristic distinguishes biosimilars from generic drugs?

<p>Biosimilars may have modifications in molecular structure. (C)</p> Signup and view all the answers

Which of the following statements about the administration routes of generic drugs and biosimilars is true?

<p>Biosimilars may require intravenous or subcutaneous administration. (D)</p> Signup and view all the answers

What factor contributes to the higher production costs of biosimilars?

<p>The requirement for extensive clinical studies. (A)</p> Signup and view all the answers

How does the immunogenicity of biosimilars raise safety concerns?

<p>Each biosimilar requires a separate evaluation due to potential differences in immunogenicity. (C)</p> Signup and view all the answers

In terms of testing requirements for biosimilars, which factor is essential for evaluation?

<p>Analysis of glycosylation patterns and aggregation. (A)</p> Signup and view all the answers

What is a notable difference in the half-lives between biosimilars and generic drugs?

<p>Biosimilars usually have longer half-lives compared to generic drugs. (A)</p> Signup and view all the answers

Which statement accurately describes the manufacturing process of biosimilars?

<p>Biosimilars are produced in living systems using complex biological processes. (B)</p> Signup and view all the answers

What must biosimilars demonstrate to achieve FDA approval?

<p>High similarity to the licensed reference product. (A)</p> Signup and view all the answers

Flashcards

Drug Release Rate

The speed at which a drug is released from a polymer system.

Mass Transfer

The movement of a drug across a polymer.

Flux

The rate of transport of drug through a polymer.

Zero-Order Release

Drug release at a constant rate over time.

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First-Order Release

Drug release rate proportional to remaining drug.

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Square Root of Time Release

Release rate proportional to the square root of time.

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Permeability

How easily a drug passes through a polymer.

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Concentration Gradient

Difference in drug concentration between inside and outside the polymer.

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Prodrugs

Inactive compounds that are converted into active drugs in the body.

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Depot Injections

Injections that release drugs slowly over time.

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Lipophilic

Fat-soluble and dissolves slowly.

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Bioerodible Microspheres

Advanced drug delivery systems where drugs are embedded in a biodegradable polymer.

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Drug Diffusion

Drug moving from high concentration areas to low concentration area.

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Biodegradable Polymer Breakdown

Polymer material breaking down gradually after a while.

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Atrogel Delivery System

Drug dissolved in liquid, forms matrix at injection site.

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Lupron Depot

Biodegradable microsphere formulation of a type of hormone agonist for extended release.

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Biologic Drug Manufacturing

The process of creating medicines derived from biological sources.

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Biologics' high cost

Biologics are expensive due to their complex production process, the need for extensive safety testing, and often limited patient populations.

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Monoclonal Antibody Production

Process of creating identical antibodies in a lab.

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Recombinant Protein Impurities

Unwanted materials such as cell debris, viruses, or contaminants from growth media found in produced proteins.

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Host cell type (manufacturing)

Different cell types like bacteria, yeast, or mammalian cells used for protein production, impacting cost and difficulty.

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Immunogenicity

The potential of a biologic to trigger an immune response in the recipient.

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Clinical Trial Phases

Stages of testing a drug's safety and efficacy: Phase 1 (safety), Phase 2 (efficacy and safety), Phase 3 (large-scale efficacy and safety).

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mRNA-based antibody therapy

A new approach to antibody therapy using mRNA.

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Wax Matrix Systems

A drug delivery system that prevents stomach irritation by preventing high local drug concentrations, without extending the overall release duration.

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Swelling Erodible Matrix Systems

Drug delivery systems utilizing hydrophilic polymers that create a swelling matrix in the stomach, slowly eroding and releasing the drug over time.

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Geomatrix System

A multilayer tablet with a drug matrix core that swells and increases surface area, controlling the hydration rate and allowing for prolonged drug release.

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Gastro Retentive Systems

Systems designed to keep the medication in the stomach for a prolonged time, allowing drug release in the stomach.

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Swelling Systems (Gastro retentive)

Gastro retentive systems using swelling polymers to prevent the dosage form from passing through the pylorus.

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AccuForm System

A type of swelling system that uses swelling polymers (like hypromellose) to create a gel-like substance, keeping the medication in the stomach for extended release.

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Coated Particle Systems

Drug delivery systems that involve coating drug particles, with dissolving or non-dissolving coats, releasing the drug.

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Prolonged Drug Release

Medication release that occurs over a longer period of time in the body, compared to instant release medication.

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mRNA-Based Therapy

A therapy that uses messenger RNA (mRNA) to deliver genetic instructions to cells, prompting them to produce specific protein products like antibodies.

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Isoelectric Point (pI)

The pH at which a protein molecule has a zero net charge, making it neutrally charged.

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Biologic Drug

A pharmaceutical product derived from a biological source, like living organisms or cells, typically proteins or antibodies.

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Protein Stability

The ability of a protein to maintain its 3D structure and function under various conditions.

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mRNA Vaccine

A vaccine that uses mRNA to instruct cells to produce a specific protein antigen, triggering an immune response.

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Biosimilar Drug

A biological medicine that is similar to an already approved biological medicine (referred to as the reference product).

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Protein Charge at Low pH

Proteins at low pH demonstrate a more positive charge because the amine groups are protonated.

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Protein Charge at High pH

Proteins at high pH demonstrate a more negative charge because the carboxyl groups are deprotonated.

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Generic Drug

Identical or bioequivalent to the innovator drug, matching in dosage, safety, and use.

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Biosimilar

A follow-on biologic (like protein/antibody) similar but not identical to the original.

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Biosimilar Evaluation

Thorough analysis of structure, purity, potency, and other characteristics needed for drug safety.

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Immunogenicity (Biosimilars)

The potential for the body to produce antibodies against a biosimilar, differing from generic drugs.

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Biosimilarity

Demonstrating high similarity to the original, licensed product as validated by the FDA.

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Biosimilar Production Costs

Often higher than generic drug production due to complex manufacturing processes and clinical studies.

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Key Differences: Biosimilars vs. Generics

Difference in size, complexity, molecular structure, production methods, administration routes, and half-lives, and the ability to form antibodies that affect the drug's action.

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Biosimilar Manufacturing

Uses living systems (e.g., cell cultures) for complex protein production, a difference from typical generic drugs.

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Study Notes

Advanced Drug Delivery

  • Aims to optimize drug delivery, with two main approaches:
    • Temporal control (controlling timing, e.g., extended release)
    • Spatial control (targeting to needed site)

Why Advanced Drug Delivery?

  • Benefits to patients:
    • Improved safety and efficacy (steady blood levels, avoiding spikes)
    • Increased convenience and compliance (reduced dosing frequency)
  • Repatenting drugs:
    • Creating extended-release versions to extend patent protection and generate revenue after patent expiry.

Ideal Drug Delivery System Characteristics

  • Delivers drug at the perfect time throughout treatment
  • Delivers drug only to the site of action

Advanced Drug Delivery Systems

  • Many different types, some mechanical (e.g., pumps)
  • Most are based on polymers.

Types of Carrier Particles

  • Carrier particles (e.g., liposomes, microspheres) used for:
    • Controlling drug release
    • Targeting drugs to specific sites

Polymers in Advanced Drug Delivery

  • Essential components, large molecules made up of repeating units (natural or synthetic)
  • Used to:
    • Control drug release rate
    • Target drug to specific sites

Mass Transfer Across Polymers

  • The movement of molecules across polymers.
  • The rate of drug release depends on mass transfer rate across the polymer.
  • Factors affecting rate are area of contact, permeability, and concentration gradient.

Patterns of Drug Release

  • Three main mathematical models:
    • Zero-order: Constant release rate over time.
    • First-order: Release rate proportional to remaining drug, decreasing over time.
    • Square root of time release: Rate decreases linearly with the square root of time.

Types of Polymer Systems for Controlled Release

  • Diffusion Devices: Drug release based on diffusion through the polymer, reservoir and matrix systems.
  • Reservoir systems: Drug dissolved in a saturated solution surrounded by a polymer membrane that controls release.
  • Matrix systems: Drug evenly dispersed in a polymer matrix, releasing drug as polymer degrades.
  • Swelling systems: Drug dispersed in a polymer matrix that swells upon contact with body fluids, expanding pores and increasing release rate.
  • Osmotic systems: Utilize osmotic pressure to force drug release. Semi-permeable membrane surrounding a drug compartment, water enters the compartment, creates pressure, forces drug release.

Chemical Controlled Systems (Bioerodible Polymers)

  • Drug dispersed in a polymer matrix that degrades over time, releasing the drug, typically by hydrolysis.
  • Advantages include no removal required (biocompatible breakdown products).

Depot Injectables

  • Long-term drug delivery technology, commonly administered subcutaneously or intramuscularly.

Suspensions

  • One of the oldest methods, involving gradually dissolving drug crystals in water or oil.

Prodrugs

  • Inactive compounds that are metabolized in the body to release the active drug moiety. Fat-soluble, stay in the depot, release gradually.

Bioerodible Microspheres

  • More advanced form of depot injectables, consisting of drug particles uniformly dispersed in a biodegradable polymer matrix.
  • Drug release through gradual polymer degradation.

Liquid Crystal Nanotubes

  • Newest technology, drug dissolved in a biocompatible solvent, which solidifies upon contact in body fluids.

Implants

  • Subcutaneously placed for long-term drug delivery, rich in fat, low blood perfusion and nerve density.
  • Polymer implants controlled release via biodegradability or pumps.
  • Membrane-controlled reservoir systems: Consist of a drug reservoir in a saturated solution, surrounded by a controlled-rate membrane, resulting in zero-order release. Example is Nexplanon.

Mechanical Implants

  • Use pumps for positive pressure delivery to specified sites.

External Pumps

  • Worn externally, positive pressure to deliver medication in fluid form, categorized as electronic or stored-energy.
  • Examples: Hospital infusion pumps, ambulatory infusion pumps, PCA pumps, Insulin pumps.

Spatial Control & Targeted Drug Delivery Methods

  • Specific sites within the body, methods include:
    • Liposomes: Phospholipid bilayer, capsule that protects and targets drugs, used to deliver various drugs.
    • Albumin Nanoparticles: Paclitaxel bound to albumin, delivering it intravenously, avoiding toxic excipients in conventional formulations.
    • Antibody-Drug Conjugates (ADCs): Antibody component targets specific cells while the cytotoxic drug destroys cells.

Biologics Workflow and Manufacturing

  • Long and expensive process (12-15 years, millions).
  • Steps involved (research and design).

Clinical Trials

  • Phase 1 (safety testing), 2 (efficacy/safety), 3 (efficacy/safety in larger population).

Factors Influencing Biologic Drug Cost & Safety

  • Manufacturing complexity, host cell type affects cost.
  • Immunogenicity and toxicity, choosing human sources reduces immunogenicity.

mRNA-Based Antibody Therapy

  • mRNA encoding targeted antibodies is introduced into cells in the body for expression.

Types of Oral Controlled Release Systems

  • Matrix Systems (dissolving and non-dissolving).
  • Gastro Retentive Systems (maintain drug in stomach for prolonged period).
  • Coated particle systems (encapsulating drug)
  • Membrane Controlled Systems.
  • Osmotically Controlled Systems.
  • Ion Exchange Systems
  • Delayed Release systems.

Transdermal Drug Delivery Patches

  • Patches deliver medication through the epidermis for systemic purposes

Key Concepts:

  • Biosimilars (similar versions of existing biologics)
  • Manufacturing processes of biologics
  • Challenges of delivering proteins and peptides
  • Various routes of administration and design choices
  • Factors impacting stability, biodegradability and target site effectiveness.

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Description

This quiz explores the principles and benefits of advanced drug delivery systems, focusing on both temporal and spatial control of drug release. It discusses the importance of optimizing drug delivery for improved patient compliance and safety, as well as the use of various carrier particles and polymers. Test your knowledge on these innovative drug delivery strategies.

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