Controlled and Novel Drug Delivery Systems (NDDS) are advanced pharmaceutical technologies designed to deliver drugs at a controlled rate, at a specific site, or over a desired period. Unlike conventional dosage forms, which release drugs immediately after administration, controlled and novel systems improve treatment outcomes, reduce side effects, and enhance patient convenience.
Why Controlled and Novel Drug Delivery?
- To maintain steady drug levels in the blood
- To reduce frequency of dosing
- To improve patient compliance
- To minimize side effects by avoiding drug peaks
- To target drugs to specific tissues or organs
- To protect sensitive drugs from degradation
Classification of Drug Delivery Systems
1. Controlled Release Systems
These systems release the drug at a predetermined rate.
- Sustained Release (SR): Releases drug slowly over an extended period
- Controlled Release (CR): Maintains constant drug concentration
- Delayed Release: Releases drug after a lag time (e.g., enteric-coated tablets)
2. Targeted Drug Delivery Systems
Deliver the drug directly to the desired site, minimizing systemic exposure.
- Liposomes
- Niosomes
- Nanoparticles
- Monoclonal antibody–based systems
3. Novel Drug Delivery Systems
Advanced technologies designed to enhance drug delivery efficiency.
- Transdermal patches
- Osmotic pump systems
- Microneedle patches
- Implants
- Floating drug delivery systems
- Mucoadhesive drug delivery
Principles of Controlled Drug Delivery
- Diffusion-controlled systems: Drug diffuses slowly through polymer membranes
- Dissolution-controlled systems: Release depends on dissolution rate of drug or coating
- Osmotic systems: Use osmotic pressure to pump drug out at constant rate
- Bio-responsive systems: Release triggered by pH, enzymes, or temperature
Materials Used in Novel Delivery Systems
- Polymers: HPMC, ethyl cellulose, PLGA
- Lipids: Used in liposomes and nanoparticles
- Hydrogels: Used in transdermal and implant systems
- Biodegradable materials: Reduce need for surgical removal
Examples of Novel Drug Delivery Technologies
1. Transdermal Patch
A medicated patch applied to the skin that delivers drug through the skin layers into the bloodstream. Example: nicotine patch, fentanyl patch.
2. Liposomes
Small vesicles made of lipid bilayers. Used for targeted delivery of anticancer and antifungal drugs.
3. Osmotic Pump Tablets
Contain a drug core and osmotic layer. Use osmotic pressure to release drug at a constant rate.
4. Implants
Placed under the skin or in specific tissues for long-term drug release. Example: contraceptive implants.
5. Floating Tablets
Remain in the stomach for prolonged release of drugs absorbed in upper GIT.
Advantages of NDDS
- Reduces frequency of dosing
- Improves therapeutic effectiveness
- Enhances patient compliance
- Decreases side effects and toxicity
- Allows use of drugs with short half-life
- Enables site-specific drug delivery
Limitations
- Higher manufacturing cost
- Complex design and testing
- Not suitable for all drugs
- Risk of dose dumping in some systems
Applications of Novel Drug Delivery Systems
- Cardiovascular drugs
- Anticancer drugs
- Insulin delivery systems
- Pain management
- Hormonal therapies
- Vaccines
Patient Counseling
- Follow dosing instructions strictly for sustained/controlled release forms
- Do not crush or chew controlled-release tablets
- For transdermal patches, apply on clean and dry skin
- Rotate patch application sites
- Report signs of irritation or allergic reactions
Detailed Notes:
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