Video summary

Week 01: Lecture 01: Fundamentals of Drug Delivery Systems-I

Main summary

Key takeaways

Educational

Main ideas / concepts covered

  • Purpose of the course/lecture

    • Introduces Novel Drug Delivery Systems (NDDS/NDDDS) within an online certification course on novel drug delivery systems.
    • Focus of Lecture 1: Fundamentals of Drug Delivery Systems – I.

  • Drug development pipeline (high-level overview)

    • Drug discovery and development occur before clinical trials.
    • Steps described:
      1. Identify a right target / pathological system to stop disease.
      2. Design/discover molecules using different scientific approaches.
      3. Perform in vitro studies and preclinical (animal) safety/toxicity.
      4. Conduct Phase 1, Phase 2, Phase 3 trials to determine safety, efficacy, and other parameters in humans.
      5. Seek regulatory approval (described as NDA: new drug approval process).
      6. After review (noted as ~2–3 years), approval leads to marketing—yet drug delivery challenges persist even after the molecule is created.

  • Why drug delivery systems are needed

    • Developing new molecules is difficult and slow, and even after an API is found, formulation challenges remain.
    • BCS (Biopharmaceutics Classification System) link:
      • Class 2 and Class 4 drugs tend to have low solubility.
      • They may require conversion into forms with improved solubility/permeability, leading to better bioavailability.
    • Beyond solubility:
      • A major challenge is delivering the drug to the target site.
      • Conventional formulations (tablets, capsules, syrups, ointments) may be insufficient for diseases like brain diseases, cancer, and infectious diseases due to:
        • Poor biodistribution
        • Low efficacy
        • Side effects
        • Lack of selectivity

  • Core concept of NDDS/NDDDS

    • Drug delivery systems are technologies/formulation approaches/methods/materials used to transport pharmaceutical compounds in the body to achieve a therapeutic effect in a safe and controlled manner.
    • Main aim:
      • Improve efficacy, safety, bioavailability, and patient compliance through:
        • Controlled release
        • Targeted delivery
        • Sustained release

  • What NDDS changes compared to conventional formulations

    • The active ingredient may remain the same, but:
      • Dose can be reduced
      • Efficacy increases
      • Safety improves
    • Mechanisms mentioned:
      • Use polymers, carriers, and formulation modifications to control release.
    • Examples of NDDS platforms listed:
      • Polymeric systems
      • Micro-needles for target-specific delivery
      • Nanoforamulations via nanotechnological approaches (enhanced solubility/permeability)
      • Long-acting injectables using polymers/ingredients
      • Site-specific transdermal systems and nanocarriers in patches
      • Pulsatile delivery systems

  • Conventional vs novel drug delivery systems (comparisons described)

    • Release profile
      • Conventional tablets/capsules: immediate release; shorter effect.
      • Novel systems: controlled/sustained/targeted release via engineering and modification; targetability is emphasized as difficult but achievable with the right materials/strategies.
    • Targeting / selectivity
      • Novel systems aim to reduce non-specific distribution.
      • Example concept:
        • Tumor targeting using pH-sensitive/temperature-sensitive polymers
        • Ligand example: folate targeting folate-overexpressed cancer cells (e.g., breast cancer).
    • Dose frequency and patient compliance
      • Conventional: frequent dosing required → lower compliance.
      • NDDS: reduced frequency → improved patient compliance.
    • Side effects and exposure
      • Conventional: more systemic exposure → higher risk of toxicity/side effects.
      • NDDS: reduced dose and better targeting → reduced side effects.
    • Duration
      • Conventional: typically shorter duration per dose.
      • NDDS: can extend activity from hours (example given ~12 hours for a capsule technology) to months (long-acting injectables/implants).
    • Stability
      • Conventional: biological molecules/temp/pH-sensitive drugs may degrade.
      • NDDS: polymers/carriers can protect drugs from enzymatic, pH, and other degradations, improving stability and bioavailability.
    • Limitations (trade-offs) mentioned for NDDS)
      • Higher cost, complexity, and regulatory hurdles
      • Reproducibility issues
      • Regulatory guidelines may be less established than for conventional dosage forms.
    • Example products/formulations mentioned:
      • Conventional: paracetamol tablets and injection
      • Novel: pegylated liposomal doxorubicin, transdermal patches, mra lipid nanoparticles (as stated)

  • Evaluation/considerations

    • Mentions evaluation of drug delivery systems and suggests references for detailed evaluation methods (no full methodology steps provided).
    • Mentions types of systems/materials:
      • PEGylated proteins
      • PEGylated liposomes
      • PEGylated nanoparticles
      • Biological molecules such as mRNA vaccines (COVID example) → suggests next generation may rely on small biological molecules.
    • Development emphasis:
      • Consider physicochemical properties of drugs/biomolecules.
      • Select appropriate materials and right technologies/processes.
    • Key development requirement stated:
      • Safety and improvement in patient compliance.

Terminology and definitions taught (detailed list)

Common release-action terminology (treated as synonymous/overlapping)

  • Control release
  • Prolonged release
  • Sustained / slow release
  • Long-acting release
  • Delayed release
  • Delayed action
  • Gradual release
  • Modified release
  • Prolonged action
  • Pulsatile release

Defined terms: Controlled vs Sustained drug delivery

  • Sustained drug delivery (definition given)

    • Delivers the drug at a predetermined/programmed rate.
    • Maintains delivery for a specific period of time.
    • Contrasts it with concentration dependence by describing:
      • Release continues to support therapeutic levels over time.
      • It is not directly dependent on the current drug concentration in the system (as described).
    • Associated concept: transcript links this behavior to zero-order release.
    • Intended effect:
      • Maintain drug concentration within therapeutic range.

  • Controlled drug delivery / zero-order controlled release (as described in the lecture)

    • Described as:
      • Drug releases at a predetermined rate for a specific period.
      • Release is independent of drug concentration.
    • Called zero-order release in the transcript.

  • Sustained / delayed/prolonged release mechanism (as described using concentration-dependence concept)

    • Drug release:
      • Begins with an initial dose for prompt therapeutic effect (loading/initial release concept).
      • Then continues as maintenance dose released more slowly.
    • Transcript describes that:
      • The sustained release behavior is dependent on concentration, associating it with first-order release (as stated).
    • Result:
      • Achieves and maintains therapeutic levels for longer duration.

Method/logic used in the lecture to explain importance (conceptual “steps”)

  • Graph concept introduced

    • A theoretical plot of:
      • X-axis: time
      • Y-axis: plasma drug concentration

  • Key concentration thresholds defined

    • Minimum effective concentration (MEC):
      • Below MEC → no efficacy.
      • Above MEC → therapeutic effect possible.
    • Minimum safe concentration:
      • Below this level → drug is safe.
      • Above it → potential toxicity (transcript mentions toxicity example with paracetamol at high dose/long duration).
    • Therapeutic range:
      • Between MEC and the minimum safe/toxic threshold.

  • Comparison of dosing strategy

    • Conventional / immediate release (single dose)
      • Drug concentration peaks and then drops.
      • Requires repeated dosing to stay within therapeutic range.
      • Repeated doses can increase patient non-compliance and toxicity risk due to exposure.
    • Zero-order controlled release
      • Drug is released at a predetermined rate for a set period.
    • Sustained release
      • Provides an initial release quickly to reach therapeutic level.
      • Then releases more slowly to maintain therapeutic concentration.
      • Leads to reduced dosing frequency and improved patient compliance.

Conclusion of the lecture

  • Summarized that the lecture covered:
    • What drug delivery systems are
    • Conventional vs novel drug delivery systems and their differences
    • Terminologies used in drug delivery systems
  • The lecture ends with a note that later lectures will cover further fundamentals.

Speakers / sources featured

  • Speaker: Dr. Satish Dawanabelli (Assistant Professor, Institute of Chemical Technology, Department of Pharmaceutical Sciences and Technology, Mumbai)

  • Sources referenced (general, not cited as documents):

    • BCS (Biopharmaceutics Classification System)
    • Regulatory approval concept: NDA (New Drug Application) / regulatory body review (no specific agency named in the transcript)

  • Named example referenced:

    • COVID-19 mRNA vaccine (mentioned as an example of next-generation biological molecules)
    • Paracetamol (example for toxicity concept)
    • Folate targeting example for cancer cells (e.g., breast cancer)
    • Example brand/product mentioned: “Spans” (described as providing ~12-hour release; brand name as stated in transcript)

Original video