الفهرس 
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Abstract
Summary
Recent research has demonstrated that using antioxidants to overcome
the occurrence of skin pathologies is a very promising approach. Several
delivery systems have been exploited for such purpose, among which are
lipid nanoparticles as solid lipid nanoparticles (SLNs), nanostructured lipid
carriers (NLCs), as well as vesicular systems as liposomes, niosomes,
transfersomes and ethosomes.
Nanostructured lipid carriers (NLCs) are lipid nanoparticles consisting
of mixtures of solid and fluid lipids, in which the fluid lipid phase is
embedded into the solid lipid matrix. On the other hand, vesicular systems
as aspasomes consist of a bilayer of ascorbyl palmitate and cholesterol
enclosing an aqueous environment. NLCs are widely used in cosmetics
enabling drug penetration into epidermal barrier compared to other
delivery systems to prevent skin aging.
Melatonin was reported to be an effective anti-oxidant. It acts as a free
radical scavenger and it has been reported to inhibit the lipid peroxidation
in skin. Therefore, the aim of this work was to prepare a highly
antioxidant lipid based/vesicular nanosystems for the treatment of
androgenic alopecia caused by oxidative stress.
The work in this thesis is divided into three chapters:
Chapter I: Preparation and characterization of highly anti-oxidant lipid
nano particulate system of melatonin (NLCs)
This chapter deals with the formulation, and characterization of melatonin-
NLCs. These NLCs were prepared by high shear homogenization method
followed by solvent diffusion, and characterized for their entrapment
efficiency, morphology using transmission electron microscopy, particle size,
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160
zeta potential, in vitro permeation, anti-oxidant potential and ex-vivo
deposition. Stability of melatonin- NLCs stored at 2-8oC was tested through
monitoring the changes in particle size and zeta potential.
The work in this chapter included the following:
1- Preparation of melatonin-NLCs by combined solvent evaporation/high
shear homogenization. Four different oils (liquid lipids) namely evening
primrose oil, olive oil, soybean oil and almond oil were used.
Investigation of the factors influencing the EE%, particle size and the
anti-oxidant activity of melatonin-NLCs namely, the effect of the type of
solid lipid used and the type of liquid lipid (oils) used was performed.
2- characterization of the prepared NLCs through the following studies:
a) Particle size, PDI and zeta potential analysis of freshly prepared melatonin
NLCs formulations were carried out using zetasizer.
b) Determination of melatonin entrapment efficiency EE% in NLCs by
using exhaustive dialysis method.
c) Measurement of the anti-oxidant potential of NLCs formulations was
carried out using the DPPH free radical assay.
d) Physical stability study on all melatonin NLCs formulations was
conducted over a storage period of three months at 2-8° C by the assessment
of the effect of storage on the particle size, charge and PDI of the
nanoparticles.
e) In vitro permeation experiments were carried out over 6 hours on the
selected formulae.
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f) selected NLC formulation was examined for morphology by transmission
electron microscopy.
g) Ex vivo deposition/permeation of the selected NLC formula on rat skin
was carried out using Franz diffusion apparatus.
The results of this work revealed the following:
1- Melatonin NLCs were successfully prepared using combined high shear
homogenization/ solvent diffusion method.
2- The EE% of melatonin in NLCs ranged from 36 to 76% owing to its
hydrophobicity, suggesting its successful incorporation within the liquid
lipid matrix.
3- NLCs particle size ranged from 303-783 nm, depending on the type of
solid lipid and liquid lipid used.
4- All of the prepared NLCs were charged, with charges ranging from (-11.8
to -19.7 mV).
5- Melatonin NLC formulae were supposed to be a successful anti-oxidant
system.
6- The selected melatonin NLCs formulations showed sustained release of
melatonin for 6 hours, and 100% release was achieved after this period of
time.
7- Melatonin NLCs displayed good storage properties as manifested by the
slight changes in particle size, polydispersity index and zeta potential
values.
8- Transmission electron microscopy displayed coarsely and somehow
spherical shaped NLCs with smooth surface
9- Ex vivo skin deposition experiments demonstrated the high potential of
the selected NLC formula (NLC2) in accumulating the drug into the
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deeper epidermal and dermal layers of the skin, and hence it was selected
for further clinical studies.
Chapter 2: Preparation and characterization of highly anti-oxidant
vesicular system of melatonin (aspasomes)
This chapter deals with the formulation and characterization of melatonin
aspasomes prepared by thin film hydration technique. characterization of the
prepared vesicles was done through the following studies: entrapment
efficiency, particle size, zeta potential, morphology using transmission
electron microscopy, in vitro permeation, anti-oxidant potential and
deposition experiments. Stability study of melatonin-aspasomes stored at 2-
8oC was tested through monitoring the changes in particle size and zeta
potential.
The work in this chapter included the following:
1- Preparation of melatonin aspasomes by thin film hydration method using
ascorbyl palmitate (ASP) and cholesterol in varied molar ratio with a
negative charge inducer (dicetyl phosphate).
2- characterization of the prepared aspasomes was done through the
following studies:
a) Particle size, PDI and zeta potential analysis of freshly prepared
melatonin aspasomal formulations were carried out using zetasizer.
b) EE% of melatonin in aspasomes.
c) Physical stability study on all melatonin aspasomes formulations was
conducted over a storage period of three months at 2-8° C by the
assessment the effect of storage on the particle size, charge and PDI of
the nanoparticles.
d) Measurement of the anti-oxidant potential of the selected melatonin
aspasome system using DPPH assay.
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e) In vitro release study on the selected melatonin aspasomal
formulae.
f) The selected aspasomal formula was examined for morphology by
transmission electron microscopy
g) Ex vivo deposition/permeation of the selected aspasomal formula on
rat skin was carried out using Franz diffusion apparatus.
The results of this work revealed the following:
1- Melatonin aspasomes were successfully prepared using the thin film
hydration method.
2- The EE% of melatonin in aspasomes ranged from 52.23 to 91.21 %
owing to the hydrophobicity of the drug, suggesting its successful
incorporation within the lipid bilayers.
3- Aspasomes particle size ranged from 287- 950 nm, depending on the
amount of ascorbyl palmitate.
4- All of the prepared aspasomes were charged, with charges ranging from
(-37.3 to -63.3) mV.
5- selected melatonin formulae systems were supposed to be a successful
anti-oxidant system.
6- selected melatonin aspasomes’ formulations showed sustained release of
melatonin for 6 hours.
7- Melatonin aspasomes displayed good storage properties as manifested by
the slight changes in particle size, polydispersity index and zeta potential
values.
8- Transmission electron microscopy displayed spherical vesicles with
smooth surface with an evident bilayer.
9- Ex vivo skin deposition experiments demonstrated the high potential
of the selected aspasomal formula (A3) in accumulating the drug
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164
into the deeper epidermal and dermal layers of the skin, and hence it
was selected for further clinical studies.
Chapter 3: Clinical evaluation of the selected NLCs and aspasomes
formulae
In this study attempts were made to examine the clinical efficacy of the
selected melatonin NLCs and aspasomes in treatment of male AGA compared
to the conventional melatonin solution.
The work in this chapter included the following:
The clinical study was conducted on 60 male patients suffering from
AGA. Patients were divided into 3 groups: group I (20 patients) were
treated with melatonin solution in phosphate buffer saline, pH 7.4, group II
(20 patients) were treated with topically applied nanostructured lipid carriers
formula NLC2 and group III (20 patients) were treated with topically applied
aspasomal formula A3 formula. In each group, all patients were instructed to
apply the provided formula once daily on affected scalp areas for a total
period of 3 months. Assessment of the clinical response was done at 16th
week (i.e. 1 month after the end of treatment) based on demographical and
diagnostic data.
The results of this work revealed the following:
1- Regarding photographic assessment, group II patients treated with NLCs
formulation displayed significantly better improvement scores compared
to group III patients treated with aspasomal formulation and group I
treated with melatonin solution.
2- Regarding hair pull test assessment, after treatment, the extent of decrease
in hair loss was significantly higher in group II patients, followed by
group III then group I.
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3-Regarding hair shaft diameter histometric assessment, after treatment, the
extent of hair diameter increase was significantly higher for group II
patients, followed by group III patients, followed by group I patients.
4- Regarding dermoscopic evaluation, in post-treated patients of AGA, it was
found to be significantly higher for group II patients followed by group
III patients and finally group I patients.
from the previous results, it can be concluded that melatonin delivery
systems adopted in the current thesis (NLCs and aspasomes) are
promising topical delivery systems for the delivery of the