Microencapsulation

1. Characterization of
Microcapsules
Prepared By: Kashf Rasheed
M Phil Pharmaceutics
Punjab University College of Pharmacy

2. Particle Size and Shape:
• Conventional light microscopy (CLM) and Scanning electron
microscopy (SEM): To analyze the shape and structure of
microcapsules
• Confocal laser scanning microscopy (CLSM): Reveals structure, surface
and core particle of microcapsule
• Fourier transform-infrared spectroscopy (FTIR): To analyze the
degradation of polymeric matrix of carrier system, and to check
interaction between polymer and drug system.

3. Carr's index and Hausner's ratio:
• Carr’s Index = [ρT - ρB / ρT] ×100
• Hausner's ratio (HR) = ρT/ρB
• Where, ρT is tapped density and
ρB is bulk density
• These parameters determine the
flow properties of
microcapsules.

4. Isoelectric point:
• It is the pH value at which the molecule carries no
electrical charge.
• Its value can affect the solubility of a molecule at
a given pH.
• The micro electrophoresis is an apparatus which
is used to measure electrophoretic mobility of
microsphere by which isoelectric point can easily
be calculated.
• The mobility is related with surface contained
charge, ionizable behavior or ion absorption
nature of microcapsules.

5. Determination of Microcapsule Yield:
• % Yield=
Weight of Microcapsules
Total expected weight of drug and polymer
×100
Extraction of sample
with 𝑪𝑯 𝟑 𝐎𝐇
Filtration And dilution
with 𝑪𝑯 𝟑 𝑶𝑯
Measure % Yield by
UV
Spectrophotometry

6. Determination of Drug Loading and
Encapsulation Efficiency:
• Drug Loading: Amount of drug loaded per unit weight of
microcapsule.
• Encapsulation Efficiency: % drug that is successfully entrapped
into microcapsule.
% Loading =
𝑾𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝑫𝒓𝒖𝒈
𝑾𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝑴𝒊𝒄𝒓𝒐𝒄𝒂𝒑𝒔𝒖𝒍𝒆𝒔
% Encapsulation efficiency =
% Actual drug content
% Theoretical drug content ×100

7. Angle of contact:
• To determine the wetting
property of microcapsule.
• To know about nature of
microcapsules in terms of
hydrophilicity an hydrophobicity.
• Measured at solid/air/water
interface by placing a droplet in
circular cell mounted above the
objective of inverted
microscope.

8. In Vitro Drug Release Studies:
• Carried out in various pH
conditions using USP rotating
basket and paddle apparatus.
• Sample is taken out after
particular time intervals and is
replaced by same medium.
• Release profile is determined
using the plot of amount
released vs time.

9. References
• Singh, Maninder & Menra, J.S.DuaMuse & Soni, Mansi & Prasad, Deo.
(2016). MICROENCAPSULATION AND ITS VARIOUS ASPECTS: A
REVIEW.. International Journal of Advanced Research. 4. 2094-2108.
10.21474/IJAR01/726.
• Sri, S. & Seethadevi, A. & Prabha, K. & Muthuprasanna, P. & Pavitra,
P.. (2012). Microencapsulation: A review. International Journal of
Pharma and Bio Sciences. 3. P509-P531.
• Microencapsulation: Methods and Industrial Applications, Second
Edition.