efficiency as shown in table 5.9-5.13 was formulated

efficiency
of 89.46 ± 2.16 %. From the results it was concluded that hot homogenization
technique followed by ultrasonication was selected as a model method for
formulation of NLC in further optimizing the formulation.

6.3.
Discussion on Preoptimization

6.3.1.
Selection of variable for optimization of formulation

The formulations F1- F17c as shown in table 5.9-5.13 was formulated with hot
homogenization followed by ultrasonication method, by altering various
formulation, process variables and evaluated for Particle Size (PS) in nm, polydispersity index (PI) and Zeta potential (ZP) in mV. From the
results obtained from Table 5.9-5.13 and Figure 5.24-5.53, the reason for
selection of formulation and process variables for optimization step is as
follows.

6.3.2. Selection of Lipid

The
formulations F1- F7 as shown in table
5.9 was formulated and evaluated by using various solid lipids like Compritol
888 ATO, Dynasan 114, Witepsol H 32, Stearic acid, Acconon-C-44, Cholesterol and
liquid lipid like softigen. From
the results, formulation F3 with Compritol 888 ATO solid lipid is selected as
the best lipid for the formulation of NLC, based on least Particle size of about
265.1 ± 9.2 nm, optimal PI of about
0.401 ± 0.02 shows that the NLC particles are well dispersed in the continuous phase
and good ZP of about                    –
34.7 ± 2.64 mV shows that the NLC particles contains good surface charge
potential and better stability. So Compritol 888 ATO and Softigen are utilized as
the lipid for further formulations. The results are shown in table 5.9 and figure 5.24-5.30.

6.3.3. Selection
of surfactant

The type of surfactants influences the Particle Size and
stability of NLC. The formulation F8 – F12 as shown in Table 5.10
was formulated by using various surfactants like Tween 20, Tween 80, Span 20,
Span 80, Sodium Lauryl Sulphate and studied their impact on PS, ZP and PI. The
results shows that formulation F11 which contains Span 80 is selected as the
best surfactant for formulation of NLC, based on less Particle size of 228.5 ± 18.2
nm, Optimal PI of 0.413 ± 0.022 which shows NLC particles are well dispersed in
the phase and high ZP of -57.4±3.48 mV which shows NLC particles contains good
surface charge potential and excellent stability. So, Span 80 surfactant is
fixed as an optimized surfactant for forthcoming formulations. The results are shown in table 5.10 and figure 5.31-5.35.

6.3.4. Selection of Co-surfactants

The co-surfactant
will acts as internal emulsifier, favors the reduction of particle size, increasing
solubility and stability of particles. different
co-surfactants like Poloxamer 188 and Polysorbate 20, 60, 80 were used for the
formulation from F13-F16 as shown in table
5.11. As per the best control in Particle Size of 147.1 ± 10.4 nm, Zeta
Potential of                         -21.6
± 2.12 mV and polydispersity index
of 0.37 ± 0.026, the formulation F13 contains poloxamer
188 was selected as the optimized co-surfactant for the formulation of further
batches of formulation. The results are shown in table 5.11 and figure
5.36-5.39.

6.3.5. Selection
of Formulation Techniques

By fitting the selected Lipid,
Surfactant and co-surfactant in the
formulation from    F17-F24 and it was
prepared by using different formulation techniques like Hot Homogenization,
Cold Homogenization, Micro Emulsification, Homogenization followed by ultrasonication as shown in table 5.12. From the results obtained
it shows that the F17 formulation prepared by Hot Homogenization Technique is
selected as the best formulation technique for the formulation of NLC, based on
less Particle size of 214.1±6.6 nm,
optimal PI of 0.427±0.028 and good
ZP of -53.4±3.98 mV. The Hot Homogenization Technique, which infers the best
results, was fixed as an selected optimized technique for the formulation of
NLC. The results are shown in table 5.12 and figure 5.40-5.47.

6.3.6. Selection of Process
Variables

The
optimized formulation from Hot homogenization technique was taken for the
selection of process variable like Ultrasonication time (5, 10 and 15 min) and Homogenization
speed (5000, 10000 and 15000rpm). The impact of Ultrasonication time and Homogenization
speed on NLC was determines by comparing their effect on PS, Zp and PI. The results are shown in Table
5.13 and Figure 5.48 – 5.53. From the results obtained the impact of
homogenization time of 15000 RPM in F17c formulation shows, best reduction in particle
size as 107.7 ± 8.2 nm; best stability by expected surface charge potential as -34.9
± 4.02 mV; good PI of 0.382 ± 0.22. So
homogenization Speed of 15000 RPM
is selected as the optimized process variable for the formulation of NLC.

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