Microspheres are small spherical particles, with a diameter of 1µm to 1000 µm These are spherical free-flowing particles consisting of proteins or synthetic polymers which are biodegradable in nature. Microcapsules are those in which entrapped substance is distinctly surrounded by a distinct capsule wall. Micromatrices are those in which entrapped substance is dispersed throughout the matrix. Gelatin is a natural polymer obtained either by partial acid or alkaline hydrolysis or by thermal or enzymatic degradation of structural animal collagen protein. Gelatin is non-expensive and does not express antigenicity in vivo and could be readily dissolved in aqueous solutions. Gelatin’s crosslinking with several agents is essentially aiming to increase its mechanical and thermal stability. Therefore, based on its unique characteristics, gelatin is widely used in the preparation of depot microsphere formulations. Screening Plackett-Burman DoE trials were employed to identify materials attributes and process parameters. Morphological analysis via SEM revealed the formation of spherical particles with smooth surface, while FTIR analysis showed the presence of strong molecular interaction between API and gelatin matrix. Leading, to formation of amorphously dispersed drug-loaded microspheres (verified via DSC and pXRD). Finally, dissolution studies showed a biphasic release profile for optimum microsphere formulation , which extended API’s release for up to 30 days following a Fickian diffusion release mechanism.

1. Formulation and Evaluation
of Gelatin Microspheres
DEPARTMENT OF PHARMACEUTICS
Presented By
Nagabhushan Shet
M. Pharm 1st Year (semester II)
BHARATI VIDYAPEETH (DEEMED UNIVERSITY) POONA COLLEGE OF
PHARMACY, PUNE

2. CONTENTS
1 4 5
Introduction
2 3
Advantages and
Disadvantages
Types of
microspheres
Method of
preparation
Case study
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Poona College of
Pharmacy
Tuesday,
March 28,
2023

3. Microspheres
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Pharmacy
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2023
 Microspheres are small spherical particles, with a diameter of 1µm to 1000 µm
 These are spherical free-flowing particles consisting of proteins or synthetic polymers
which are biodegradable in nature.
Microsphere
Microcapsules Micromatrices
 Microcapsules are those in which entrapped substance is distinctly
surrounded by a distinct capsule wall.
 Micromatrices are those in which entrapped substance is dispersed
throughout the matrix.

4. 4
Poona College of
Pharmacy
Tuesday,
March 28,
2023
Advantages Disadvantages
• Improve bioavailability.
• Provide constant and prolonged therapeutic
effect.
• Provide constant drug concentration in blood.
• Decrease dose and toxicity.
• Protect the drug from enzymatic and photolytic
cleavage so it is best for drug delivery of
protein.
• Reduce the dosing frequency and thereby
improve patient compliance.
• The cost is more.
• Reproducibility is less.
• Process conditions like change in temperature,
pH, solvent addition, and evaporation may
influence the stability of core particles.
• Degradation of product due to heat, hydrolysis,
oxidation, solar radiation or biological agents.

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Poona College of
Pharmacy
Tuesday,
March 28,
2023
Bio adhesive
microspheres
Floating
microspheres
Radioactive
microspheres
Magnetic
microspheres
Polymeric
microspheres
• Biodegradable
polymeric
microsphere
• Synthetic polymeric
microsphere
Types of
microspheres

6. Methods of preparation
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Pharmacy
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March 28,
2023
 Single emulsion technique
 Double emulsion technique
 Solvent evaporation
 Phase separation coacervation technique
 Spray drying and spray congealing
 Solvent extraction
 Polymerization

7. Gelatin Microsphere
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Poona College of
Pharmacy
Tuesday,
March 28,
2023
 Gelatin is a natural polymer obtained either by
partial acid or alkaline hydrolysis or by thermal or
enzymatic degradation of structural animal
collagen protein.
 Gelatin is non-expensive and does not express
antigenicity in vivo and could be readily dissolved
in aqueous solutions.
 Gelatin’s crosslinking with several agents is
essentially aiming to increase its mechanical and
thermal stability. Therefore, based on its unique
characteristics, gelatin is widely used in the
preparation of depot microsphere formulations.

8. Case study
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Poona College of
Pharmacy
Tuesday,
March 28,
2023
 Full Journal Title – American
Association of Pharmaceutical
Scientists
 Publisher – Springer Nature
 Scope of the journal –
pharmacology, toxicology, and
pharmaceutics, pharmaceutical
science
 Cite score – 6.7
 Impact factor – 4.8

9. Aim: Development and Evaluation of Diclofenac Sodium Intra-articular Gelatin Microsphere.
Objective:
 To develop a mechanically and thermally stable gelatin microsphere.
 To develop a targeted drug delivery system.
 Risk assessment analysis using Plackett – Burman screening experimental design.
Method of preparation: Emulsion crosslinking procedure based on a single water-in-oil emulsion.
Materials:
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Pharmacy
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March 28,
2023
Chemicals Functions
Gelatin type A and B Natural polymer
Phosphate buffer saline tablets Buffer
Micronized DCL API
Glutaraldehyde Cross-linking agent
Olive oil / sesame oil Base
Span 60 and Span 80 Surfactant
Sodium metabisulfite Antioxidant
Acetone Solvent

10. Drug profile
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Pharmacy
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March 28,
2023
Drug Diclofenac
IUPAC sodium;2-[2-(2,6-
dichloroanilino)phenyl]acetate
Molecular formula C14H10Cl2NNaO2
Molecular weight 318.1
Nature Crystalline solid
Category NSAID
Log P 4.51
pKa 4.15

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2023
Evaluation
Table no. 1 : Experimental domain according to the Placket- Burman screening experimental design applied in the study

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Pharmacy
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2023
Table no.2: Results of particle size distribution (PSD), polydispersity index
(PDI), and Drug loading according to the Placket-Burman screening
experimental design.
Table no.3 : ANOVA results for the employed screening
Plackett-Burman experimental design.
Results and discussions

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Pharmacy
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2023
Fig. 1. Main effect plots for the screening Plackett-Burman experimental
design
Table no. 4: Control stratergy for the production of Intra-articular gelatin
DCL microspheres, Along with the proposed optimum formulation.

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Pharmacy
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March 28,
2023
Fig.2. SEM morphological analysis of
the optimum DCL-loaded gelatin
microsphere at 100µ𝑚 𝑎𝑛𝑑 50 µ𝑚
Fig. 3, a) DSC , b) pXRD and c) ATR-FTIR analysis of optimum DCL-loaded gelatin microspheres
285.6
4

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Pharmacy
Tuesday,
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2023
Fig no. 4 Drug release profile of optimum DCL-
loaded gelatin microspheres compared to pure API.
Table no.4 Dissolution data model fitting results for the
employed drug release kinetic model.

16. Conclusion
Screening Plackett-Burman DoE trials were employed to identify materials attributes and process
parameters.
Morphological analysis via SEM revealed the formation of spherical particles with smooth surface,
while FTIR analysis showed the presence of strong molecular interaction between API and gelatin
matrix.
Leading, to formation of amorphously dispersed drug-loaded microspheres (verified via DSC and
pXRD).
Finally, dissolution studies showed a biphasic release profile for optimum microsphere formulation ,
which extended API’s release for up to 30 days following a Fickian diffusion release mechanism.
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Pharmacy
Tuesday,
March 28,
2023

17. References
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Pharmacy
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2023
Theory:
 N.K.Jain, controlled and Novel Drug Delivery, CBS Publishers and Distributors,
NewDelhi, First edition 1997.
 Dong Z, Meng X, Yang W, Zhang J, Sun P, Zhang H, Fang X, Wang DA, Fan C.
Progress of gelatin-based microspheres (GMSs) as delivery vehicles of drug and cell.
Materials Science and Engineering: C. 2021 Mar 1;122:111949.
Case study:
 Nakas A, Dalatsi AM, Kapourani A, Kontogiannopoulos KN, Assimopoulou AN,
Barmpalexis P. Quality risk management and quality by design for the development of
diclofenac sodium intra-articular gelatin microspheres. Aaps Pharmscitech. 2020
May;21:1-7.