Stabilized phosphorus ylides, versatile intermediates in synthetic organic chemistry can be prepared by the novel reaction of dialkyl acetylenedicarboxylates (DAAD), triphenylphosphine (TPP) and acids such as phenols, imides, amides, enols, oximes and alcohols. The reaction involves an intermediate formed by the 1:1 conjugate addition reaction of the TPP to DAAD and concomitant protonation of the intermediate by an acid leads to vinyltriphenylphosphonium salts. The salts are unstable intermediates and converted to stabilized phosphorus ylides via Michael addition reaction. The stabilized phosphorus ylides are able to take part in the normal intramolecular Wittig reactions but they are not generally able to participate in the normal intermolecular Wittig reactions. The intermolecular Wittig reactions of the ylides are observed only with highly electron-poor carbonyl groups such as indane-1,2,3-trione. The ylides are converted to electron-poor alkenes via elimination of TPP in solvent-free conditions. Almost all of the final products are valuable families of compounds. †Dedicated to Professor Issa Yavari on the occasion of his 59th birthday.

High drug loading is one of the important issues in the drug delivery research, especially the drug delivery system by oral administration. If high drug loading carriers are utilized the times of drug intake could be significantly reduced. Accordingly in this study, ordered mesoporous SBA-15 modified with (3-aminopropyl) triethoxysilane (APTES) was used as a carrier for nonsteroidal anti-inflammatory drug and optimization of the loading process was done. SBA-15 silica material with rope-like morphology was synthesized and modified by post-synthesis method with APTES. The synthesized SBA-15 and modified SBA-15 were characterized by XRD, SEM, thermal analysis and FT-IR spectroscopy. Loading optimization experiments were performed by changing the factors affecting the drug loading, such as temperature, time, stirring rate, Ibuprofen/SBA-15 ratio. The results of drug delivery experiments showed that the surface modification of SBA-15 with amino groups significantly increases the drug loading and decreases the drug delivery rate.

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Methotrexate is one of the most effective drugs that is commonly used in the treatment of cancer. However, its application is limited due to low solubility, high toxicity and rapid metabolism. Therefore, in the present study, worm-like polymeric nanoparticles as carrier of methotrexate were prepared using biodegradable copolymers (mPEG-PCL). The impact of nanoparticles' geometry on the loading, delivery and drug's anti-cancer activity was investigated. The di-block copolymer mPEG-PCL was being synthesized by a ring opening polymerization of ɛ-caprolactone in the presence of mPEG as the initiator and Sn(oct) as the catalyst. It was used for the preparation of worm-like micelles and coated with silica, so that their structures are stable after drying. The synthesized copolymers and nanoparticles were characterized by FTIR, HNMR, GPC, XRD, TGA, DLS, and FE-SEM analyses. The efficiencies of drug loading and release of nanoparticles as in vitro, was studied by high performance liquid chromatography. The MTT method was used to estimate the toxicity on MCF-7 cell category. The obtained results showed that the nanoparticles were worm-like particles with less than 150 nm diameter and about 1 µm length. The loading and encapsulation efficiencies of drug by the worm-like nanoparticles were 3.5 ± 0.14% and 65.6 ± 0.12%, respectively, while they were obtained as 2.1 ± 0.08% and 26 ± 0.10%, respectively, for spherical nanoparticles. The methotrexate diffusional behavior of worm-like nanoparticles was compared with that of the spherical ones. On the other hand, the anti-cancer activity of MTX-loaded nanoparticles was more than the free drug. The results of the MTT assay showed strong and dose-dependent inhibition of cell (MCF-7 category) growth by the nanoparticles compared with MTX. The inhibitory concentrations (IC i.e. reduction viability of cell to 50%) obtained for worm-like, spherical nanoparticles and free drug (incubation times 72 h) were 8.25 ± 0.20, 9.15 ± 0.17, 12.28 ± 0.15 µg/mL, respectively. It can be concluded that application of non-spherical nanoparticles is a better and more effective strategy for controlled and slow release of methotrexate in the treatment of cancer.

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Hyaluronic acid (HA), as a safe biomaterial with minimal immunogenicity, is being employed in a broad range of medical applications. Since unmodified HA has a high potential for biodegradation in the physiological condition, herein, an HA-based cross-linked hydrogel was formulated using polydimethylsiloxane-diglycidyl ether terminated (PDMS-DG) via epoxide-OH reaction. The formation of HA-PDMS hydrogel was confirmed using FTIR, NMR, and FESEM. Temperature demonstrated a critical role in the physicochemical properties of the final products. Gel-37, which formed at 37 C, had a higher modification degree (MD) and more stability against hyaluronidase and oxidative stress than the hydrogel formulated at 25 C (Gel-25). In addition, the swelling ratio, roughness, and porous network topology of Gel-25 and Gel-37 were different. The rheology measurement indicated that HA-PDMS hydrogel had a stable viscoelastic character. The hydrogel was also biocompatible, noncytotoxic, and considerably stable during 7-months storage. Overall, various determined parameters confirmed that HA-PDMS hydrogel is worth using in different medical applications.

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