الفهرس 
General IntroductionOnly 14 pages are availabe for public view
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Abstract
Direction towards natural products in treating diverse diseases is very promising, especially with multitargeted agents as resveratrol (RES). RES is the most well-known natural polyphenol stilbenoid that can be isolated from more than 70 plant species as red grapes, berries and peanuts. It has gained a tremendous interest owing to its anti-oxidant, anti-inflammatory, anti-proliferative, anti-diabetic, anti-obesitic, anti-cancer and anti-microbial activities. Remarkably, the therapeutic and preventive role of RES against malfunctions occurring in idiopathic pulmonary fibrosis (IPF) could pave the way for RES intervention in management of IPF via its antioxidant and anti-inflammatory activities. Local non-invasive pulmonary delivery of RES can achieve direct access to the targeted site with fast onset of action, decrease the drug dose, reduce systemic side effects related to the drug and improve patient compliance. It can also diminish the problems associated with oral delivery of RES viz. poor water solubility and bioavailability in addition to first pass metabolism. As an attempt to maximize the therapeutic efficacy of RES, development of nanoparticle-based drug formulations for pulmonary delivery was adopted to sustain the drug release, so keeping its concentration at therapeutic level to exert its action locally and avoid rapid systemic absorption.
Chapter I dealt with formulating and optimizing RES-loaded bovine serum albumin nanoparticles (BSA NPs) using Box-Behnken design, aiming to obtain NPs with the smallest particle size (PS) and polydispersity index (PDI) in addition to the highest zeta potential (ZP), entrapment efficiency (EE%), loading efficiency (LE%) and yield% values among all the prepared formulations. The studied independent factors were BSA concentration (A), ethanol:water ratio (B), glutaraldehyde amount (C), and the drug concentration (with respect to albumin amount) (D), while the responses were PS, PDI, ZP, EE%, LE% and yield%. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), transmission electron microscope (TEM) examination and in-vitro drug release were performed on the optimized formula.
The optimized RES-loaded NPs, chosen by Design Expert software, attained suitable PS, uniform size distribution as well as high stability and entrapment efficiency. They were characterized by PS of 177.67 ± 0.95 nm, PDI of 0.046 ± 0.01, ZP of -47.27 ± 6.01 mV, EE% of 98.73% ± 0.36, LE% of 6.01% ± 0.02 and yield% of 84.14% ± 1.83. The optimized formula appeared as spherical particles with smooth surface, regular structure, and narrow size distribution. DSC analysis and XRPD confirmed the encapsulation of RES in the optimized NPs which exhibited sustained drug release, controlled by the Fickian diffusion according to Korsmeyer-Peppas model.
In Chapter II, the optimized NPs obtained in Chapter I were spray-dried with different carriers (mannitol, dextran sulfate, trehalose, leucine, glycine, aspartic acid and glutamic acid) to prepare RES-loaded spray-dried composite microparticles (SDCMs) suitable for pulmonary delivery via dry powder inhaler (DPI). The delivered spray-dried (SD) powders should be able to dissociate into their constituting NPs upon contact with lung fluids to escape alveolar macrophages (AMs) uptake. The effect of different carriers on the quality of the fabricated SD powders were assessed rigorously by determining the yield%, powder flow, particle size, aerodynamic diameter, drug content, moisture content, powder re-dispersibility, and in-vitro aerosolization properties. Scanning electron microscope (SEM) was used to reveal the morphology of the selected composite particles, while the drug system interactions were evaluated using DSC and XRPD techniques. Additionally, the in-vitro drug release from selected SD powders was evaluated by adopting the dialysis bag method. TEM analysis was used to visualize the NPs after their recovery from the selected SDCMs.
The best aerosolization behavior was attained from using leucine with fine particle fraction (FPF) of 75.74%, followed by glycine with FPF of 54.7%. The selected Leu-SD and Gly-SD powders exhibited acceptable yield% (˃ 65%), with excellent flow properties and long-term stability. They also displayed the smallest aerodynamic diameter (<4 µm) and residual moisture content (<3.5%). DSC thermograms and X-ray diffractograms confirmed the amorphization of RES and its encapsulation in the Leu-SD and Gly-SD powders that showed a biphasic sustained drug release pattern. SEM images revealed hollow doughnut-shaped particles of Leu-SD powder and smooth-surfaced particles of Gly-SD powder, while TEM images of NPs, liberated after redispersion of the Leu-SD and Gly-SD powders, confirmed the ability of the spray drying process to convert NPs into SDCMs with preservation of the desired properties of the original NPs.
The aim of Chapter III was to evaluate the therapeutic effectiveness and safety of the selected formulations. The biological activity, in terms of hydroxyproline (Hyp), tumor necrosis factor- α (TNF-α) and matrix metalloproteinase-9 (MMP-9) levels, was assessed in bleomycin (BLM)-induced mice, and it was compared with intraperitoneal (IP) administration of the RES solution. On the other hand, the safety of the formulations was evaluated in healthy non-induced mice, and the biological activity was compared to that of the negative control group.
The pharmacodynamic study strongly revealed that RES-loaded SDCMs, either Leu-SD or Gly-SD powder, showed a higher significant effect than the IP RES solution in attenuating the induced PF, indicating that targeting the site of action through the non-invasive inhalation route, in addition to sustaining the drug release by encapsulating the RES in BSA NPs could achieve higher efficacy in treating the BLM-induced PF. The safety of the prepared SD powders was also confirmed.
Altogether, these findings indicate that in addition to leucine, the glycine amino acid, which is not commonly used yet, is very promising in the formulation of DPIs. Both optimized RES-loaded SDCMs, Leu-SD and Gly-SD, are considered promising candidates for the treatment of pulmonary fibrosis.