130 JOURNAL OF COSMETIC SCIENCE
(Tween 20) of cosmetic grade was acquired from Vetec Quimica Fina (Brazil), Polysorbate 80
(Tween 80) of cosmetic grade was acquired from Vetec Quimica Fina (Brazil), and glyceryl
monostearate and sesame oil, both of cosmetic grade, were acquired from Croda (Campinas,
Brazil). Capric and caprylic acid triglycerides (Captex, cosmetic grade) were purchased from
ABITEC Corporation (Ohio, USA). Mineral oil of cosmetic grade was purchased from
Penreco (Indiana, USA), and Poloxamer 188 of cosmetic grade was purchased from BASF
(Germany).
AVB QUANTIFICATION METHOD
The chromatographic method was adapted from Abid et al.,24 considering the recommended
criteria from the International Council for Harmonization of Technical Requirements
for Pharmaceuticals for Human Use (ICH) for validation of chromatographic methods
regarding linearity, precision, accuracy, and limits of detection and quantification (ICH
Q6B). Specifications: test procedures and acceptance criteria for biotechnological/biological
products—scientific guideline. The chromatographic parameters used were: Zorbax
Eclipse (Agilent) XDB – C18 column 150mm × 4.6mm, 3.5 µm, with precolumn C18
12.5 × 4.6 mm, 3.5 µm (Agilent), maintained at 30°C. Detection was carried out using a
photodiode array at 360 nm. The mobile phase was composed of acetonitrile (ACN) and
water (90:10 v/v), at a 1 mL/min−1 flow. The injection volume was 10 µL.
SELECTION OF EXCIPIENTS FOR NLC DEVELOPMENT
AVB SOLUBILITY
The solubility of AVB was evaluated in liquid lipids: oleic acid, sesame oil, mineral oil,
isopropyl myristate, capric acid triglycerides, and caprylic acid triglycerides. Excess amount
of AVB was weighed (150 mg) and transferred to amber glass bottles, where 1 mL of each oil
was added. Each oil was tested in triplicates. The samples were each vortexed for 1 minute
and then placed in an orbital shaker (KS 4000, IKA®, Germany) at a speed of 150 rpm,
at 37°C, for 24 hours. The samples were then filtered through 0.45 µm polyvinylidene
fluoride (PVDF) microfiltration membranes, were diluted with 10 mL ACN, and AVB
solubility was then quantified by high-performance liquid chromatography (HPLC).
THERMOGRAVIMETRY AND DIFFERENTIAL THERMAL ANALYSIS
The thermal evaluation of AVB and raw lipid excipients, as well as the AVB:excipients physical
mixture (1:1 m/m), was carried out in a DTG-60 thermobalance (Shimadzu, Kyoto, Japan),
with simultaneous measurement of mass loss (TG/DTG) and melting events (DTA), under a
nitrogen atmosphere (50 mL/min−1), with a heating rate of 10 °C.min−1, and a temperature
range of 25–500°C. Platinum crucibles were used for the analysis of 5 mg of each sample.
FOURIER TRANSFORM INFRARED SPECTROSCOPY
Attenuated total reflectance Fourier transform infrared spectra were obtained on a
Varian 640-IR (Varian Medical Systems Inc., Jundiaí, Brazil). AVB, lipid excipients, and

131 ImprovedPROVED AVB PhotostabilityOTOSTABILITY UsingING NLCs
AVB:lipid-based excipients binary mixtures (1:1 m/m) were analyzed at wavelengths of
4,000–600 cm−1 with a resolution of 4 cm−1, using attenuated total reflection (ATR).
Around 2 ± 1 mg were used to evaluate the solid excipients and 20 uL (about a drop) of
the liquids. Each sample was subjected to 64 scans to obtain the spectra.
DEVELOPMENT AND IN VITRO CHARACTERIZATION OF THE
NANOSTRUCTURED LIPID CARRIERS
NANOSTRUCTURED LIPID CARRIER OBTAINING
After the evaluation of AVB compatibility with NLC excipients, the formulations were
obtained by the phase inversion method previously described by Shinoda et al.25 Water
and oil phase components were weighed separately. The lipid, surfactant, and AVB were
weighed and then added to the same container. For the water phase, water was weighed in a
separate container. Both phases were heated to a temperature of 80–90°C and, subsequently,
the water phase was poured into the oil phase under mechanical stirring at 400 rpm and
then left to stabilize for 10 minutes. The formulation (Table 1) was submitted to high-
pressure homogenization at 400 bar in a LV1 Microfluidizer (Microfluidics Corporation,
Massachusetts, USA). 0.5% AVB was added to the oil phase.
PHYSICOCHEMICAL CHARACTERIZATION OF NLCS
The formulations were evaluated regarding their macroscopic aspect, average particle
diameter, polydispersity index (PdI), zeta potential, and encapsulation efficiency (EE%).
Color, homogeneity, presence, or absence of coalescence or precipitate were visually
evaluated. The average diameter and PdI were evaluated by dynamic light scattering using
a ZetaSizer Nano S (Malvern Instruments Ltd., Worcestershire, UK) using a 1/40 dilution
in ultrapure water. Zeta potential was evaluated by electrophoretic mobility in a ZetaPlus
equipment (Brookhaven, New York, USA) using a 1/40 dilution in ultrapure water. The
EE% was evaluated by the indirect method, in which 1 mL of the NLC dispersion was
centrifuged (SIGMA 3-18K Centrifuge®, SciQuip, Shrewsbury, UK) at 12,000 rpm for 20
minutes. The collected supernatant was diluted with ACN, homogenized, and quantified
by HPLC. Drug EE was calculated according to Eq. 1.
EE (%)Amount of AVB in the NLC
Amount of AVB add in the formulation. 1000 =× (Eq. 1)
Table I
Percentual Composition of NLC Formulations Evaluated for the
Encapsulation of AVB
Composition F1 F2 F3
Carnauba wax 3.5 3.5 2.5
Isopropyl myristate 1.5 1.5 2.5
Sorbitane trioleate (Span 85) 1.25 1.75 1.89
Polysorbate 80 (Tween 80) 3.75 5.25 5.11
Water qs 100 qs 100 qs 100