Transcript ti̇tanyum di̇oksi̇t kati li̇pi̇t nanoparti̇külleri̇

Ebru BAŞARAN, Müzeyyen DEMİREL, Yasemin YAZAN
Anadolu University, Faculty of Pharmacy, Department of Pharmaceutical Technology 26470 Eskişehir- TURKEY
Cyclosporine A (CsA) is a powerful immunosuppressive active agent mainly used for
Particle sizes (Figure 1) and the zeta potentials (Figure 2) of the formulation remained unchanged during
autoimmune diseases and graft rejections after organ transplantations [1]. Topical
the storage at different conditions (25ºC±1ºC, 40ºC±1ºC, 4ºC±1ºC) for a period of 6 months.
application of CsA is preferred for the ocular treatment of disorders after corneal
Stability of the lipid structure analyzed by XRD (Figure 3), FT-IR (Figure 4) and 1H-NMR (Figure 5) showed
transplantation and dry eye syndrome [2].
that these data support the DSC data (Figure 6) indicating the stability of the formulations for 6 months.
Solid lipid nanoparticles (SLN) were introduced as alternative carrier systems for
controlled release of pharmaceutical and cosmetic active compounds [3]. Particles
of the system remain in the solid state at room temperature and therefore the
mobility of incorporated drug is reduced which is a prerequisite for controlled drug
release [4]. Possibility of controlled drug release and drug targeting, increased drug
stability, high drug payload, incorporation of both lipophilic and hydrophilic drugs,
avoidance of organic solvents and no problem with respect to large scale production
and sterilization were the proposed advantages of SLNs [5].
Figure 1. Particle size measurements of FD4 formulation
Figure 2. Zeta potential measurements of FD4 formulation
during the storage time
during the storage time
Systemic absorption of CsA is quite low and there is interindividual variation in
plasma concentrations depending on the dosage form applied and the story of the
patient [6]. Therefore, in this study, cationic SLNs were prepared, aiming the ocular
delivery of CsA with an attempt to decrease the interindividual variation and thus to
increase its topical absorption.
MATERIALS
Cyclosporine-A
Novartis, Switzerland
Active agent (Gift)
Dynasan® 116
Condea, Germany
Solid lipid
Stearylamine
Fluka, USA
Cationic agent
Benzalconium chloride
Fluka, Denmark
Antimicrobial agent
Tween® 80
Merck, Germany
Surfactant
Figure 5. 1H-NMR spectra of
Figure 3. XRD spectra of FD4 formulation
Figure 4. FT-IR spectra of FD4 formulation
METHODS
FD4 formulation
SLN formulation (Table 1) was prepared by hot homogenization technique [4].
Homogenization was achieved with Ultraturrax (T25, IKA) at a stirring rate of 13500
rpm for 5 minutes, at 85ºC±1ºC.
Table 1. Composition of the formulation
Dynasan® 116
CsA
Stearylamine
Benzalconium chloride
[a]
Tween® 80
Code
FD4
[b]
[c]
Figure 6. DSC thermograms of FD4 formulation during the storage time at 25ºC±1ºC [a], 40ºC±1ºC [b] and 4ºC±1ºC [c]
(%)
(%)
(%)
(%)
(%)
6
0.1
1.5
0.01
4
In Vivo Studies
CsA was determined in the aqueous and vitreous
As the sterility of the ocular formulations is necessary, the formulation was sterilized
by autoclaving at 121°C for 20 minutes.
humour samples for 48 hours (Figure 7). Detection of
CsA in the vitreous humour showed the efficient
Particle size and zeta potential measurements were carried out by Malvern Nano ZS
penetration of the drug to the deeper layers of the
and the structure of the solid lipid was analyzed using differential scanning
eyes. Similarity in the analysis results demonstrated
calorimetry (DSC-60, Shimadzu), X-Ray Diffractometry (XRD) (RIKAGU D/Max-3C),
that interindividual variance did not affect the
Fourier Transform Infrared Spectrophotometry (FT-IR) (Perkin Elmer Spektrum 2000)
absorption level of CsA.
Figure 7. CsA concentrations in aqueous and vitreous humour samples
and solid state NMR Spectrophotometry (1H-NMR).
Stability of the formulation was monitored for 6 months at different conditions
(25ºC±1ºC, 40ºC±1ºC, 4ºC±1ºC).
In vivo studies were carried on the sheep. Formulation was applied topically to one
According to the in vitro tests results, cationic SLN formulation remained stable during the storage
of the eyes and the other eye remained untreated as a reference. At appropriate time
period of 6 months. After the topical application of the formulation to the eyes, detection of CsA at the
intervals, sheep were sacrificed and the aqueous and vitreous humour samples were
deeper layers, and no existence of interindividual variance in the CsA concentrations showed the
collected and analyzed by enzyme immune assay analyzer.
efficiency of SLN formulation on the absorption of such a problematic drug.
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