This document provides an overview of solid lipid nanoparticles (SLNs) including their advantages and disadvantages, principles of drug release, methods of preparation, analytical characterization, applications, and routes of administration. SLNs are submicron colloidal carriers composed of physiological lipids dispersed in water or aqueous surfactant solutions. They can be prepared using various methods such as high pressure homogenization, ultrasonication, solvent evaporation, microemulsion, and spray drying. Key advantages of SLNs include improved bioavailability, biocompatibility, stability, and ability to control drug release. Common characterization techniques include measuring particle size, zeta potential, molecular weight, and density. SLNs have applications in drug delivery for cancer, vaccines, brain

1. SOLID LIPID NANOPARTICLE
Presented By..
Mr. Wagh Pankaj N.
M.Pharm.(IInd Sem)
1
Department Of Pharmaceutics
R.C.Patel Institute Of Pharmaceutical Education and Research, Shirpur.
2015-16

2.  Introduction
 Advantages & disadvantages
 Principal of drug release
 Methods of Preparation
 Analytical characterization of SLNs
 Applications of SLNs
 Routes of administration
 References
CONTENTS:
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3. Solid lipid nanoparticles
 The solid lipid nanoparticles(SLN’s) are submicron colloidal carriers
which are composed of physiological lipid, dispersed in water or in an
aqueous surfactant solution.
 They consist of macromolecular materials in which the active principle
is dissolved, entrapped, and or to which the active principle is adsorbed
or attached.
 No potential toxicity problems as organic solvents are not used.
 SLNs are spherical in shape & diameter range from 10-1000nm.
 To overcome the disadvantages associated with the liquid state of the
oil droplets, the liquid lipid was replaced by a solid lipid shown in fig, 3

4. The reasons for the increasing interest in lipid based system are :
1. Lipids enhance oral bioavailability and reduce plasma profile variability.
2. Better characterization of lipoid excipients.
3. An improved ability to address the key issues of technology transfer and
manufacture scale-up.
Fig. 1: Structure of solid lipid nanoparticle (SLN)
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5. Advantages of SLN
1) Control and target drug release.
2) Excellent biocompatibility.
3) Improve stability of pharmaceuticals.
4) High and enhanced drug content.
5) Easy to scale up and sterilize.
6) Enhanced bioavailability of entrapped bioactive compounds.
7) Much easier to manufacture than biopolymeric nanoparticles.
8) No special solvent required. 5

6. 9) Conventional emulsion manufacturing methods applicable.
10) Raw materials essential the same as in emulsions.
11) Can be subjected to commercial sterilization procedures.
Disadvantages of SLN
1) Particle growth.
2) Unpredictable gelation tendency.
3) Unexpected dynamics of polymeric transitions.
4) Poor drug loading capacity.
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7. Principles of drug release from SLNs
The general principles of drug release from lipid nanoparticles are as
1. Crystallinization behaviour of the lipid carrier and high mobility of
the drug lead to fast drug release.
2. Higher surface area due to smaller particle size in nanometer range
gives higher drug release.
3. Slow drug release can be achieved when the drug is homogenously
dispersed in the lipid matrix. It depends on type and drug
entrapment model of SLN.
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8. Methods of preparation of solid lipid nanoparticles
1. High pressure homogenization
A. Hot homogenization
B. Cold homogenization
2. Ultrasonication
3. Solvent evaporation method
4. Microemulsion based method
5. Supercritical method
6. Spray drying method
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It is a reliable and powerful technique, which is used for the
production of SLN. High pressure homogenizers push a liquid with
high pressure (100–2000 bar) through a narrow gap (in the range of
A few microns). The fluid accelerates on a very short distance to
very high velocity (over 1000 km/H). Very high shear stress and
cavitations forces disrupt the particles down to the submicron
range. Generally 5 -10% lipid content is used but up to 40% lipid
content has also been investigated.
Two general approaches of HPH are :-
Hot Homogenization.
Cold Homogenization.
1) High Shear Homogenization:

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A) Hot Homogenization technique:
Melting of lipid
Dissolution of the drug in the melted lipid
Mixing of the preheated dispersion medium & drug lipid melt
Premix using a stirrer to form a coarse pre-emulsion
High pressure homogenization at a temp.
above the lipid melting point
o/w- nano emulsion
Solidification of nano emulsion by cooling down to room
temp.
Solid lipid nanoparticle

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Advantages:
Disadvantages:
1) temperature induce drug degradation.
2) partitioning effect.
3) complexity of the crystallization.
1) Easy to handle.
2) High concentration of surfactant and co-surfactant are not required.
3) Organic solvent free method

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B) Cold Homogenization Technique:
Melting of the lipid
Dissolution of the drug in the melted lipid
Solidification of the drug loaded lipid in liquid
nitrogen or ice
Grinding in a powder mill (50-100mm
particle)
Dispersion of the lipid in the cold aqueous
dispersion medium
Solid lipid nanoparticle

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Advantages:
1)Low capital cost.
2)Demonstrated at lab scale.
1) Larger particle sizes & broader size distribution.
2) does not avoid thermal exposure but minimizes it.
Disadvantages:

14. 2) Ultrasonication or high speed homogenization:
SLNs are also prepared by ultrasonication or high speed homogenization
techniques.
For smaller particle size combination of both ultrasonication and high
speed homogenization is required
Advantages:
1) Equipment used is very common
2) No temperature induced drug degradation
Disadvantages:
1) Potential metal contamination
2) Broader particle size distribution ranging
into micrometer range.
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3) Solvent emulsification-evaporation technique
Drug + lipid are dissolved in water immiscible
solvent (toluene, chloroform)
Emulsification in aq. Phase o/w emulsion
Solvent evaporation at room
temp.& reduced pressure.
Solid lipid nanoparticle

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Advantages:
1) Avoidance of any thermal stress.
2) Continuous process
Disadvantages:
1) Use of organic solvents.
2) Extremely energy intensive process.

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4) Micro emulsion based method:
Melting of lipid
Add aq. Solution of drug to melted lipid
Add surfactant & co-surfactant at temp.above the melting point of
lipid
Formation of clear w/o solution
Formed w/o micro emulsion is added to mixture of water
surfactant,& co-surfactant under mechanical stirring
Formation of suspension of lipid particle
Wash with dispersion medium by ultra-filtration system
Solid lipid nanoparticle

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Advantages:
1) Low mechanical energy input.
2) Theoretical stability.
Disadvantages:
1) Extremely sensitive to change.
2) Labor intensive formulation work.
3) Low nanoparticle concentration

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Can be prepared by Rapid Expansion of Supercritical Carbon dioxide
solution methods(RESS)
Carbon dioxide with 99.99% is good solvent.
5) By Using Supercritical fluid:
Advantage:-
 Solvent less processing.

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6) By Using Spray Drying Method:
Spray drying method is a cheaper method than lyophilization.
This method causes particle aggregation due to high temperature,
shear forces and partial melting of the particle. The best result by
spray drying method was obtained with SLN concentration of 1% in
solution of trehalose in water or 20% trehalose in ethanol water
mixture(10:90 v/v)
Disadvantage:-
particle aggregation due to high temperature, shear forces & partial
melting of particles.

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[I] Measurement of particle size
1) Photon correlation spectroscopy
2) Transmission electron microscopy
3) Scanning electron microscopy
[II] Measurement of Zeta Potential
 Allows predictions about the storage stability of colloidal dispersion
 Zeta potential under 30 mV are required for full electrostatic
stabilization.
Characterization of SLNs:

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[III]Molecular weight
 Gel chromatography
 Atomic force microscopy
[IV] Density
 Helium compression pychnometry
 Contact angle measurement

23. Routes of administration:
1. Parentral administration
2. Oral administration
3. Rectal administration
4. Nasal administration
5. Respiratory delivery
6. Ocular administration
7. Topical administration 23

24.  Solid lipid nanoparticle as potential new adjuvant for vaccines.
 Solid lipid nanoparticles as a targeted carrier for anticancer drug
to solid tumor.
 Solid lipid nanoparticles for delivering peptides and proteins.
 Solid lipid nanoparticles for targeted brain drug delivery.
 Solid lipid nanoparticles for parasitic diseases.
 Solid lipid nanoparticles for topical use.
 Solid lipid nanoparticle applied to the treatment of malaria.
 Solid lipid nanoparticles in tuberculosis disease.
 SLN in cosmetic and dermatological preparations.
Applications of SLN:
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Conclusion :
Lipid particle drug delivery technology present considerable
opportunities for improving medical therapeutics, but the technology
potential remains unrealized. Their applicability in the encapsulation of
various drug. In the number of research works has been successfully
carried out in this area. It would result in a simultaneous improvement in
the quality, efficacy, and safety profile of drug.

26. REFERENCES:
1) S. P. Vyas and R. K. Khar, Targeted and Controlled Drug Delivery
System, 1st Edition, 2002, CBS Publication, PP.- 249-277.
2) N. K. Jain, Controlled and Novel Drug Delivery, 1st edition, 2001,
Reprint 2003, CBS Publication, PP.- 408-423.
3) K. H. Ramteke, S. A. Joshi & S. N. Dhole, A review on Solid
Lipid Nanoparticle, IOSR Journal Of Pharmacy, Vol-2, PP. 34-44.
4) P. Ekambaram, B. Abdul Hasan Sathali and K. Priyanka, Solid
Lipid Nanoparticles: A Review, Scientific Review & Chemical
Communications, PP.- 80-102.
5) Rahul Nair, K. S. Arun Kumar, K. Vishnu Priya, M. Sevukarajan,
Recent Advances in Solid Lipid Nanoparticle Based Drug Delivery
System, Journal of Biomedicine Science and research, Volume
3(2), 2011, PP.- 368-384
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Thank you