الفهرس 
Preparation and optimization of magnolol loaded ufasomesOnly 14 pages are availabe for public view
 |  | from | 279 |  |  |
| | | from | 279 | | |
Abstract
Summary
Skin cancer is the most widely diagnosed type of cancer in Caucasian populations. Basal cell carcinoma (BCC) represents 70% while squamous cell carcinoma (SCC) represent 25% of non-melanoma skin cancer. Nanotechnology-mediated approach has been considered one of the most powerful strategies to enhance skin penetration of various small as well as large molecular weight drugs for the treatment of various skin disorders including skin cancer. Nanocarriers could achieve a sustainment in drug release, hence reduce adverse effects such as skin irritation, skin scaling, swelling and inflammation caused by repetitive application of topical medications previously reported for topical skin cancer treatment such as 5-fluorouracil which limited their use in management of disease.
The aim of work in this thesis was to provide a new treatment option with a natural product such as Magnolol (Mag) with no reported side effects for controlling non-melanoma skin cancer. Mag is a lignan, an organic compound isolated from the stem bark and root of Magnolia officinalis or Magnolia grandiflora. Mag ability to enhance apoptosis, affect different signaling pathways and cause cell cycle arrest at G2/M phase are the possible mechanisms responsible for its activity in skin cancer. The poor aqueous solubility, low oral bioavailability due to extensive first pass metabolism and high binding to plasma protein resemble a challenge for delivery to Mag. Therefore, topical delivery of Mag to its site of action through tailored nanocarriers such as ufasomes was suggested to insure its efficacy for the treatment of skin cancer.
In this context, a vesicular delivery system such as ufasomes was adopted for Mag loading to enhance its stability and allow for better permeation and skin deposition. Ufasomes were prepared by the unsaturated fatty acids; oleic acid and HDA- based vesicles were prepared using 10-hydroxydecanoic acid (HDA) by thin film hydration technique. Organogels were also selected for topical delivery of the optimized Mag-ufasomal suspensions. Full characterization, ex vivo drug permeation and skin deposition studies of both developed systems were conducted accordingly. In vivo assessment of the chosen Mag-loaded formulae using DMBA induced skin cancer in animal model was also performed.
The thesis is divided into three chapters:
Chapter 1: Preparation and optimization of magnolol loaded ufasomes
Chapter 2: Preparation and characterization of organogel formulations for topical delivery of magnolol loaded ufasomes.
Chapter 3: In vivo anti-cancer evaluation of magnolol loaded ufasomes and organogel formulations.
Chapter 1: Preparation and optimization of magnolol loaded ufasomes
In this chapter, Mag-loaded ufasomes and vesicles were prepared by thin film hydration method using OA as the commonly used carrier compared to HDA as a novel naturally derived fatty acid. Different formulations were prepared and statistically evaluated according to a Box-Behnken design in terms of PS, PDI, ZP, and EE. Morphology of the selected ufasomal formulae were visualized using HR-TEM. Moreover, the in-vitro drug release, ex-vivo permeation and skin deposition were assessed for efficient Mag skin delivery.
from the results obtained it was found that:
• Thin film hydration technique was successfully employed for preparation of both OA and HDA based vesicles.
• Preliminary studies were conducted to initially optimize the process parameters and formulation conditions by assessing the physical description, PS and PDI of the prepared formulae.
• A Box-Behnken design was implemented to statistically optimize the formulation variables; the concentrations of fatty acid, surfactant, and drug, each at three levels, for each fatty acid type either OA or HDA. The PS, PDI, ZP and EE were the measured responses.
• The prepared ufasomes were successfully formed where their PS and PDI ranged between 156.40 ± 1.56 and 836.60 ± 397.90 nm, 0.168 ± 0.014 and 0.790 ± 0.231. High negative magnitudes of ZP values were attained varying from – 44.1 ± 7 to – 90.1 ± 3 mV. All Mag-loaded ufasomal formulations showed high EE of more than 63% to almost complete drug loading (” " ~ " ”97%).
• TEM imaging confirmed the spherical morphology of the produced vesicles. DSC guaranteed the encapsulation of Mag within ufasomal formulations.
• In vitro release studies showed complete release of Mag within 24 h from F-O1 and F-O2 and controlled release pattern from F-O3.
• Ex-vivo permeation studies revealed the enhanced permeation of Mag from all ufasomal formulations F-O1 > F-O2 > F-O3 compared to drug suspension.
• Skin deposition experiments demonstrated that F-O2 provided the highest drug retention, which confirms its choice as a successful nanocarrier for topical delivery of Mag.
• All optimized formulations were stable under refrigeration up to 4 months.
Chapter 2: Preparation and characterization of organogel formulations for topical delivery of magnolol loaded ufasomes.
In this chapter, Pluronic lecithin OGs were selected for topical delivery of Mag-loaded ufasomes. All OG formulations were characterized for organoleptic, rheological properties, morphology imaging using SEM and drug content. The effect of OG on Mag release, permeation and skin deposition was evaluated and compared to free drug in OG and non-OG formulations.
from the results obtained it was found that:
• Plain and loaded organogels were successfully prepared where they constituted of an oil phase composed of lecithin, jojoba oil and isopropyl myristate and an aqueous phase containing Pluronic® F-127 and water/ufasomal dispersion, both adjusted at a ratio of 20:80 (w/w).
• On characterization, the prepared OGs were opaque, white in color, odorless with homogenous consistency and good spreadability.
• The produced OG formulations attained a reasonable gelation time ranged from 58 ± 5.65 to 124.00 ± 1.41 sec. and a gelation temperature from 20.3 ± 0.38 to 22.4 ± 0.1°C.
• All OG formulations showed uniform drug distribution with drug content ranging from 92.22 ± 0.91 to 100.45 ± 0.77%.
• The pH range of all OG preparations were within acceptable range of 6.20 ± 0.14 to 8.00 ± 0.07 indicating good skin tolerability.
• Rheological studies confirmed that the OG exhibited shear thinning flow where the viscosity decreased on increasing the rate of shear which is important for topical application.
• SEM imaging was representative to OG showed irregular network structures with wrinkled surfaces.
• The DSC confirmed the drug amorphization and its entrapment and internal arrangement within the OG.
• In vitro release studies across dialysis membrane showed complete release of Mag within 24 h from all OG formulations compared to drug suspension.
• Ex-vivo permeation studies revealed the enhanced permeation of Mag from all OG formulations; OG-F-O1 > OG-F-O2 > OG-F-O3 compared to OG-D.
• Skin deposition studies showed that Mag retention was higher for ufasomal dispersions compared to its corresponding OG formulations.
• OG-F-O3 was selected for delivery of Mag during in vivo studies due to its high enhancement ratio relative to its vesicles suspension (F-O3), It was also used for comparison to test the anti-cancer effect of HDA compared to OA
Chapter 3: In vivo anti-cancer evaluation of magnolol loaded ufasomes and organogel formulations.
In this chapter DMBA induced skin cancer mice model was employed to evaluate the effect of the prepared Mag-loaded formulations and particularly the impact of HDA as anti-cancer agent in skin cancer treatment. The three ufasomal suspensions (F-O1, F-O2, F-O3) were evaluated in comparison to OGs (OG-D and OG-F-O3). Also, a prophylactic treatment using F-O2 was also tested as it showed promising results of permeation and skin deposition in Chapter 1. Hence, the in vivo study was performed on 8 groups distributed as follows; group I: Negative control, group II: Positive control, group III: F-O1, group IV: F-O2, group V: F-O3, group VI: OG-F-O3, group VII: OG-D, group VIII: prophylactic treatment with F-O2. The prophylactic treatment with F-O2 was started one week prior to induction. The induction of skin cancer with DMBA was continued for groups II to VII for 4 weeks till the observation of papillomas > 1 mm; then treatment started and continued for one more month.
During cancer induction, the mice body weights, tumor size and number of papillomas were assessed. After treatment, GSH and LDH assays were analyzed along with Ki67 immunohistochemistry for the different treatment groups compared to negative and positive controls. Histopathological examinations of skin tumor samples were also performed.
from the results obtained it was found that:
• The lowest average number of papillomas was observed in group VIII receiving prophylactic treatment of (F-O2) followed by group VI, V and IV which received treatments with the respective formulae; OG-F-O3, F-O3 and F-O2.
• The groups IV, V and VI treated with F-O2, F-O3 and OG-F-O3 respectively also showed significant increase of GSH levels and significantly low MDA levels which indicate low oxidative stress.
• The least expression of Ki-67 was detected in group VIII receiving prophylactic treatment of (F-O2) followed by group VI and V treated with OG-F-O3 and F-O3.
• Histopathological studies confirmed that groups V, VI and VIII demonstrated the best antitumor activities.
• The chemo-preventive effect was successfully achieved in group VIII treated with F-O2 as prophylaxis.
• The formulations OG-F-O3 and F-O3 were considered the best treatment options for skin cancer.
• The superiority of HDA-based formulations; F-O3, OG-F-O3 as well F-O2 as prophylaxis in attenuating DMBA induced skin cancer was proven.