Microparticles or microspheres are defined as small, insoluble, free flowing spherical particles consisting of a polymer matrix and drug. and sized from about 50 nm to about 2 mm. The term nanospheres is often applied to the smaller spheres (sized 10 to 500 nm) to distinguish them from larger microspheres.

1. MICROCAPSULE/ MICROSPHERES:- TYPES, PREPARATION & EVALUATION
PRODIPTA CHAKRABORTY
19HMPS06, M1
DEPARTMENT OF PHARMACEUTICS
HIMALAYAN PHARMACY INSTITUTE

2. Microparticles or microspheres are
defined as small, insoluble, free
flowing spherical particles consisting
of a polymer matrix and drug. and
sized from about 50 nm to about 2
mm. The term nanospheres is often
applied to the smaller spheres (sized
10 to 500 nm) to distinguish them
from larger microspheres.

3.  Microcapsule:
consisting of an encapsulated core
particle. Entrapped substance
completely surrounded by a distinct
capsule wall.
 Micromatrix:
Consisting of homogenous
dispersion of active ingredient in
particle. Microcapsule Micromatrix

4.  Bioadhesive microspheres
 Magnetic microspheres
 Floating microspheres
 Radioactive microspheres
 Polymeric microspheres
 Biodegradable polymeric
microspheres
 Synthetic polymeric microspheres

5.  Controlled release for longer
period of time (like 1-3 months).
 Frequency is reduced and hence
patient compliance is increased.
 Constant release and hence no
peaks and troughs in concentration
of drug.
 Low dose and hence toxic effect is
less.
 Targeting the tissue is possible.
 Other organ toxicity is less.
 No distribution through out the
body (no dilution effect)

6.  Intended mainly for parenteral
route which causes pain.
 Forms a depot in tissue or muscle
for longer period and hence may
produce pain when muscle
activities are done.
 Once administered, it is difficult to
take back the dose.
 Polymer may produce toxic
effects.
 High cost.

7. Polymers used in the Microsphere
preparation:
Synthetic Polymers :
Non-biodegradable –
 PMMA
 Acrolein
 Epoxy polymers
Biodegradable-
 Lactides and Glycolides copolymers
 Polyalkyl cyanoacrylates
 Polyanhydrides

8.  Natural Materials 
 Proteins
 Albumins
 Gelatin
 Collagen
 Carbohydrates
 Starch agarose
 Carrageenan
 Chitosan  Chemically modified
carbohydrates
 Poly(acryl)dextran
 Poly(acryl)starch

9.  Single Emulsion techniques
 Double emulsion techniques
Polymerization techniques:
Normal polymerization
Interfacial polymerization
 Coacervation phase separation
techniques
 Emulsification-solvent evaporation
method
 Spray drying and spray congealing
 Brace process

10.  ORAL DELIVERY
 PARENTERAL DELIVERY

11.  PARTICLE SIZE.
 PARTICLE SHAPE.
 DENSITY DETERMINATION.
 ISOELECTRIC POINT.
 CAPTURE EFFICIENCY.
 RELEASE STUDIES.
 ANGLE OF CONTACT.

12.  The prepared batches of microspheres were characterized for their micromeritic
properties (Particle size, angle of repose, bulk density, tapped density and Carrs
index) and encapsulation efficiency as per the standard procedures reported in
literatures.The in vitro dissolution of batch EC5 was carried out in 900 ml of pH 1.2
Buffer as the dissolution medium using USP Type II apparatus apparatus at 75 rpm.
The temperature was maintained at 37 ± 0.5°C. The dissolution was carried out for
24 hours. The sampling volume was 5 ml. The time points included were 10 mins to
2 hrs. The absorbance’s of the sample at different time intervals were carried out
using UV visible spectrophotometer (UV 1800, Shimadzu) at λmax of 242 nm. The
drug release was calculated using calibration curve subjected to various kinetic
models such as zero order and first order to study the mechanism of release of drug
from microspheres.

13.  MICROSPHERES IN VACCINE
DELIVERY. Eg ; Diphtheria toxoid ,
Tetanus toxoid.
 TARGETED DRUG DELIVERY. Eg ;
ocular, eye (cornea).etc
 CONTROLLED RELEASE. Eg ; GI
tumors, Bone tumors.
 CHEMOEMBOLIZATION.
 IMMUNO MICROSPHERES

14. Review: Radioactive Microspheres
for Medical Applications,
International journal of
Pharmaceutics 282 (2004) 1-
18,Review polymer microspheres
for controlled drug release.
https://pharmawiki.in/wp-
content/uploads/2014/01/Formula
tion-and-evaluation-of-
microspheres.pdf
N.K.Jain ,Controlled and novel drug
delivery edited by reprint 2007
pg.no.236-255.

15. Thank you