Ndds unit II notes b.pharmacy

 Novel drug delivery systems BP704T NOTES UNIT II

 Unit II syallabus

Microencapsulation: Definition, advantages and disadvantages, microspheres/microcapsules,

microparticles, methods of microencapsulation, applications.

Mucosal Drug Delivery system: Introduction, Principles of bioadhesion / mucoadhesion, concepts,

advantages and disadvantages, transmucosal permeability and formulation considerations of buccal

delivery systems

Implantable Drug Delivery Systems: Introduction, advantages and disadvantages, concept of implants and

osmotic pump

Some important questions from unit II

1. Define microparticles. Discuss the coaservation phase separation method for manufacturing of

microparticles.

2. What is the size range of microparticles and nanoparticles?

3. Give merits of microencapsulation. Explain detailed methodology of emulsion technique for formulation of

microcapsules.

4. Write a note on microencapsulation and give their applications.

5. Discuss the process of microencapsulation by spray drying method.

6. Describe in brief about techniques of microencapsulation.

7. Explain any one method of preparation of microparticles. Describe the following evaluation parameters of

microparticles: particle size and in vitro release.

8. Write short note on polymers for microparticles.

9. Discuss in-vitro release and release kinetics of microcapsules.

10. Describe characterization of Nano and micro particles

11. Write detailed note on any two: i) transdermal patch ii) nanoparticles iii) liposome

12. What is the principle of the working of an elementary osmotic pump? Or, Discuss osmotic pump as drug

delivery system.

Microencapsulation:

DEFINITION

Microencapsulation is a process by which very tiny droplets or particles of liquid or solid material

are surrounded or coated with a continuous film of polymeric material.

Microencapsulation may be defined as the process of surrounding or enveloping one substance

within another substance on a very small scale, yielding capsules ranging from less than one micron

to several hundred microns in size.”

 It is mean of applying thin coating to small particle of solid or droplet of liquid & dispersion.

 Microencapsulation is a process by which solids, Liquids or even gases may be enclosed in

microscopic particles by formation of thin coatings of wall material around the substances.

 Particle size: 50-5000 micron.

 2 phases: a) Core material

 b) Coating material

 The product obtained by this process is called as micro particles, microcapsules, microsphere,

coated granules, pellets.

ADVANTAGES

Multiparticulate drug delivery systems offer outstanding advantages to experts and patients, such as:

1. Choice of dosage form for the desired drug delivery route (peroral tablets, parenteral injections);

2. Modified and targeted (even site-specific) drug release and delivery;

3. More expectable pharmacokinetics with reduced intra- or inter-subject variability;

4. More homogenous distribution in the physiological environment;

5. Stable fixed-dose combinations of drugs;

6. Less dose-dumping;

7. Individual therapy (e.g., for pediatric or geriatric population);

8. Improving stability of the medicinal preparations;

9. Isolating the constituents to ensure better compatibility;

10. Innovative products with a prolonged life cycle through patient protection.

From the viewpoint of technology, microencapsulation provides several advantages:

1. Protect the core from the environment.

2. Masking an unpleasant taste.

3. Preserving volatiles or the viability of the cells.

4. Separating incompatible substances.

5. Protecting the body from the side effects.

6. Optimizing, prolonging, or targeting the effect of a drug.

DISADVANTAGES

1.Higher product costs due to:

- More expensive excipients in the formulations.

- More sophisticated equipment and processes.

- Stricter quality control.

2. Requires skill.

 Difficult to obtain continuous and uniform film.

 Some constituents may not meet the requirements for biocompatibility and biodegradation.

MICROSPHERES/MICROCAPSULES

 Microspheres are small spherical particles, with diameter 1 μm to 1000 μm.

 Microspheres can be characterized as matrix systems in which the drug is homogeneously

dispersed, either dissolved or homogenously suspended.

 Microcapsules are heterogenous particles where a membrane shell is surrounding the core forming

a reservoir.

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