Hassan M. Ghonaim

Asymmetrical N4,N9-Diacyl Spermines: SAR Studies of Nonviral Lipopolyamine Vectors for Efficient siRNA Delivery with Silencing of EGFP Reporter Gene

Our aim is to study the effects of varying the two acyl moieties in synthesized N(4),N(9)-diacyl spermines on siRNA formulations and their delivery efficiency in cell lines. Six novel asymmetrical lipopolyamines, [N(4)-cholesteryloxy-3-carbonyl-N(9)-oleoyl-, N(4)-decanoyl-N(9)-oleoyl-, N(4)-decanoyl-N(9)-stearoyl-, N(4)-lithocholoyl-N(9)-oleoyl-, N(4)-myristoleoyl-N(9)-myristoyl-, and N(4)-oleoyl-N(9)-stearoyl]-1,12-diamino-4,9-diazadodecane, were assessed for their abilities to bind to siRNA, studied using a RiboGreen intercalation assay, and to form nanoparticles. Their siRNA delivery efficiencies were quantified in FEK4 primary skin cells and in an immortalized cancer cell line (HtTA) using a fluorescein-tagged siRNA, and compared with formulations of N(4),N(9)-dioleoyl-1,12-diamino-4,9-diazadodecane and of a leading transfecting agent, TransIT-TKO. Transfection was measured in terms of siRNA delivery and silencing of EGFP reporter gene in HeLa cells. By incorporating two different acyl moieties, changing their length and oxidation level in a controlled manner, we show efficient fluorescein-tagged siRNA formulation, delivery, and knock-down of EGFP reporter gene. N(4)-Oleoyl-N(9)-stearoyl spermine and N(4)-myristoleoyl-N(9)-myristoyl spermine are effective siRNA delivery vectors typically resulting in 89% cell delivery and gene silencing to 34% in the presence of serum, comparable with the results obtained with TransIT-TKO; adding a second lipid chain is better than incorporating a steroid moiety.

Varying the chain length in N4,N9-diacyl spermines: non-viral lipopolyamine vectors for efficient plasmid DNA formulation

The aims of this work are to study the effect of varying the chain length in synthesized N4,N9-diacyl spermines on DNA condensation and then to compare their transfection efficiencies in cell lines. The five novel N4,N9-diacyl lipopolyamines: N4,N9-[didecanoyl, dilauroyl, dimyristoyl, dimyristoleoyl, and dipalmitoyl]-1,12-diamino-4,9-diazadodecane were synthesized from the naturally occurring polyamine spermine. The abilities of these novel compounds to condense DNA and to form nanoparticles were studied using ethidium bromide fluorescence quenching and nanoparticle characterization techniques. Transfection efficiency was studied in FEK4 primary skin cells and in an immortalized cancer cell line (HtTA), and compared with a saturated (distearoyl) analogue and also with the non-liposomal transfection formulation Lipogen, N4,N9-dioleoyl-1,12-diamino-4,9-diazadodecane. By incorporating two aliphatic chains and changing their length in a stepwise manner, we show efficient circular plasmid DNA (pEGFP) formulation and transfection of primary skin and cancer cell lines. Two C14 chains (both saturated or both cis-monounsaturated) were efficient transfecting agents, even in the presence of serum, but they were too toxic. N4,N9-Dioleoyl spermine efficiently condenses pDNA and achieves the highest transfection levels with the highest cell viability among the studied lipopolyamines in cultured cells even in the presence of serum.

Optimization of Gabapentin Release and Targeting Absorption, Through Incorporation into Alginate Beads

Aims: 1) To study the effect of some formulation variables on drug load, encapsulation efficiency, swelling ratio, mucoadhesion and drug release. 2) Optimize the mucoadhesion capabilities for targeting drug absorption and releasecontrolling capabilities of algi nate beads. Methodology: Alginatebeads were prepared by dripping sodium alginate gel into calcium chloride solution and then dried overnight at ambient temperature. The effects of alginate concentration, cross linker concentration, cross linking time, vol

Efficacy and In Vitro Cytotoxicity of Nanostructured Lipid Carriers for Paclitaxel Delivery

Paclitaxel (PTX) is an anticancer drug having poor aqueous solubility and low bioavailability. Formulation of PTX into Nanostructure lipid carriers (NLC) could be a potential way to enhance PTX aqueous solubility and bioavailability hence increases efficacy and decreases side effects. Eight PTX-NLC formulae were prepared using homogenization-ultrasonication technique. Characterization of the nanoparticles was done by transmission electron microscopy and by measurement of particle size, poly dispersibility index and zeta potential. Encapsulation efficiency, drug loading, and in vitro release were measured. Particle size ranged between 172.8 ± 0.8 to 378.2 ± 1.8 nm and zeta potential between -18.6 ± 0.4 to -28.1 ± 1.2 mV. High EE and DL were obtained due to incorporation of liquid lipid and the in vitro release showed prolonged time dependent release compared to Taxol®. NLC-3 had the best results among the eight prepared formulae. In vitro cytotoxicity of NLC-3 was evaluated on MCF-7 cell line and compared to pure PTX powder and Taxol®. These findings show that NLC is a potential carrier to improve efficacy and enhance PTX delivery.

Self-assembled complex formulations of lipid-aminoglycoside conjugates:Nanoparticles for efficient gene and siRNA delivery

Purpose: To model and interpret drug distribution in the dermis and underlying tissues after topical application which is relevant to the treatment of local conditions. Methods: We created a new physiological pharmacokinetic model to describe the effect of blood flow, blood protein binding and dermal binding on the rate and depth of penetration of topical drugs into the underlying skin. We used this model to interpret literature in vivo human biopsy data on dermal drug concentration at various depths in the dermis after topical application of 6 substances. This interpretation was facilitated by our in vitro human dermal penetration studies in which dermal diffusion coefficient and binding were estimated. Results: The model shows that dermal diffusion alone cannot explain the in vivo data and blood and/or lymphatic transport to deep tissues must be present for almost all of the drugs tested. Conclusion: Topical drug delivery systems for deeper tissue delivery should recognise that blood/ lymphatic transport may dominate over dermal diffusion for certain compounds.