2458 Despite dramatic improvements in treatment over the past 40 years, acute lymphoblastic leukemia (ALL) remains one of the most common causes of death from disease in childhood. Glucocorticoids are among the most effective agents used in the treatment of lymphoid malignancies, and patient response to treatment is an important determinant of long-term outcome in childhood ALL. In spite of its clinical significance, the molecular basis of glucocorticoid resistance is still poorly understood. The aim of this study was to develop an experimental model system to define clinically relevant mechanisms of glucocorticoid resistance in childhood ALL. An in vivo model of childhood ALL has been developed in our laboratory, using patient biopsies established as xenografts in immune-deficient nonobese diabetic severe-combined immunodeficient (NOD/SCID) mice. This model is highly representative of the human disease (Lock et al., Blood, 99: 4100-4108, 2002). The in vivo responses of these xenografts to the glucocorticoid dexamethasone (DEX) correlated significantly with patient outcome (p 1 μM) in xenografts from six patients, five of whom died of their disease. In contrast, four DEX-sensitive xenografts (IC50 values 2-fold in sensitive xenografts within 8 hours of treatment. In contrast, Bim induction was dramatically attenuated in DEX-resistant xenografts. These results have identified a clinically significant and novel mechanism of glucocorticoid resistance in childhood ALL, which occurs downstream of receptor-ligand interactions, but upstream of the signalling pathway resulting in Bim induction and apoptosis.

Novel mechanisms of glucocorticoid resistance in childhood acute lymphoblastic leukemia.

The terms 'antioxidant', 'oxidative stress' and 'oxidative damage' are widely used but rarely defined. This brief review attempts to define them and to examine the ways in which oxidative stress and oxidative damage can affect cell behaviour both in vivo and in cell culture, using cancer as an example.

Biochemistry of oxidative stress

Curcumin (diferuloylmethane) is a yellow pigment present in the spice turmeric (Curcuma longa) that has been associated with antioxidant, anti-inflammatory, anticancer, antiviral, and antibacterial activities as indicated by over 6,000 citations. In addition, over one hundred clinical studies have been carried out with curcumin. One of the major problems with curcumin is perceived to be the bioavailability. How curcumin should be delivered in vivo, how bioavailable is it, how well curcumin is absorbed and how it is metabolized, is the focus of this review. Various formulations of curcumin that are currently available are also discussed.

http://www.e-crt.org/upload/pdf/crt-46-2.pdf

Recent developments in delivery, bioavailability, absorption and metabolism of curcumin: The golden pigment from golden spice

We investigated the effects of inhibitors of clathrin-mediated endocytosis (chlorpromazine and K(+) depletion) and of caveolae-mediated uptake (filipin and genistein) on internalization of FITC-poly-l-lysine-labeled DOTAP/DNA lipoplexes and PEI/DNA polyplexes by A549 pneumocytes and HeLa cells and on the transfection efficiencies of these complexes with the luciferase gene. Uptake of the complexes was assayed by fluorescence-activated cell sorting. Lipoplex internalization was inhibited by chlorpromazine and K(+) depletion but unaffected by filipin and genistein. In contrast, polyplex internalization was inhibited by all four inhibitors. We conclude that lipoplex uptake proceeds only by clathrin-mediated endocytosis, while polyplexes are taken up by two mechanisms, one involving caveolae and the other clathrin-coated pits. Transfection by lipoplexes was entirely abolished by blocking clathrin-mediated endocytosis, whereas inhibition of the caveolae pathway had no effect. By contrast, transfection mediated by polyplexes was completely blocked by genistein and filipin but was unaffected by inhibitors of clathrin-mediated endocytosis. Fluorescence colocalization studies with a lysosomal marker, AlexaFluor-dextran, revealed that polyplexes taken up by clathrin-mediated endocytosis are targeted to the lysosomal compartment for degradation, while the polyplexes internalized via caveolae escape this compartment, permitting efficient transfection.

Role of clathrin- and caveolae-mediated endocytosis in gene transfer mediated by lipo- and polyplexes

Tyrosinase is a multi-copper enzyme which is widely distributed in different organisms and plays an important role in the melanogenesis and enzymatic browning. Therefore, its inhibitors can be attractive in cosmetics and medicinal industries as depigmentation agents and also in food and agriculture industries as antibrowning compounds. For this purpose, many natural, semi-synthetic and synthetic inhibitors have been developed by different screening methods to date. This review has focused on the tyrosinase inhibitors discovered from all sources and biochemically characterised in the last four decades.

https://northumbria-test.eprints-hosting.org/id/document/268389

A comprehensive review on tyrosinase inhibitors.

Bromelain is a mixture of proteolytic enzymes presence in all tissues of pineapple (Ananas comosus). It is known for clinical use as debridement for burn treatment. However, it is easily degraded by light, high temperature and pH. Nanoemulsion of bromelain is promising to increase its stability. In this study, we investigated the nanoemulsion of bromelain and its formulation into gel preparation in order to increase its efficacy for the burn treatment. Spontaneous or self-nanoemulsifying was applied to form nanoemulsion of bromelain (NEB). Bromelain was incorporated in various types of oil phase i.e virgin coconut oil (VCO), olive oil, vitamin E acetate and combination of both vitamin E acetate and VCO. Cremophor RH 40 was used together with polyethyleneglycol 400 to reduce oil-water interface tension. The stability of NEB in different oil phases was evaluated including particle size, polydispersity index, zeta potential, enzymatic activity and nanoemulsion morphology. Further, the most stable NEB was incorporated into hydrophilic gel matrix. An in vivo evaluation was carried out in hot plate-induced burn skin of New Zealand rabbit. Treatment of wounds was given by applying the preparations: NEB and the nanoemulsion bromelain-CMC gel (GKNB), using a standard protocol. As a control, untreated rabbit burned skin was provided. The efficacy of NEB was evaluated by observing wound contraction, eschar score, erythemic score, pus score and edema. After 14 days of storage, nanoemulsion using vitamin E acetate was found to be the most appropriate formula to encapsulate bromelain with good physical and chemical stabilities. This formula shows clear visual appearance with globule diameter of 74.37 nm, narrow size distribution, high loading efficiency of 97.96 %, and ability to maintain the enzymatic activity of bromelain compared to gel preparation using corresponding bromelain nanoemulsion. The vitamin E acetate nanoemulsion system shows better reduction in wound contraction until the 14th day of observation as well as other relevant parameters for wound healing effects. Taken together, bromelain formulated with the vitamin E acetate nanoemulsion improved the stability of bromelain and showed better activity to heal burnt skin on the animal model tested. The gel matrix retained the release of bromelain resulting in lower wound healing effect but it may have prolonged activity.

Bromelain Encapsulated in Self Assembly Nanoemulsion Exhibits Better Debridement Effect in Animal Model of Burned Skin

Objective: The formula of curcumin nanoemulsion had been established in our previous research. Encapsulation of curcumin in this nanocarrier system is expected to increase the bioavailability of the curcumin after oral administration, hence giving better effects. The objective of this study is to formulate tablet containing curcumin nanoemulsion for oral delivery. Methods: The formulation of curcumin nanoemulsion was done by using oil phase: glycerylmonooleate, cremophor RH 40 as surfactant and polyethylene glycol 400 as co-surfactant in the ratio of 1:8:1, and was dispersed in water with mild stirring. Tablet was produced by wet granulation method, using 9% PEG 6000 as lubricant, polyvinylpyrrolidone 5% as binder, mannitol as filler, 1% sodium chloride as glidant and 2% sodium lauryl sulphate as lubricant. Tablet evaluation was performed according to standard quality of tablet. Results: Curcumin nanoemulsion with particle size of 125.7± 1.029 nm and percentage of drug encapsulated of 99.52% was formed. Tablet containing this nanoemulsion has good physical characteristics with hardness of 5.95 kg/cm2 and 99.79% of curcumin dissolved in 60 minutes. Curcumin nanoemulsion formulated into tablet dosage form still maintained the particle size of 134±1.45 nm when the tablet was dispersed in water. Conclusion: Taken together, curcumin nanoemulsion was able to be formulated into solid dosage form, resulting good physical characteristic of the tablet while maintaining the nanoemulsion form when the tablet was dispersed in water. The comparison of the dissolution profile between tablet curcumin and tablet containing curcumin nanoemulsion should be done to ensure that the tablet formulation using curcumin nanoemulsion is better.

Formulation of tablet containing curcumin nanoemulsion

Electrospinning is one of techniques used for nanofiber fabrication as drug delivery systems. Curcumin possesses challenging properties as it has low solubility and poor absorption. Incorporation of curcumin into nanofiber is expected to enhance solubility and absorption. In this study, curcumin loaded nanofiber for oral delivery has been developed. Nanofibers were synthesized from curcumin and Polyvinylpyrrolidone (PVP) with mass ratio of 1:10 using electrospinning method. Various PVP concentration from 5 to 10 % (w/v) were used. To further assess the variation in the physical characteristics of fiber, the influence of Polysorbate 20, a nonionic surfactant, was studied. Electrospinning of curcumin-PVP nanofiber with the addition of Polysorbate 20 yielded fiber with overall diameter of 350-400 nm. In the absence of Polysorbate 20, the diameter was higher i.e 540-660 nm. The highest diameter was observed in highest PVP concentration at 10% (w/v). Drug release study showed that more than 50% of curcumin has been released within 45 minutes in all formulas. Initial rapid release occurred in the formula containing Polysorbate 20. As a summary, the presence of Polysorbate 20 reduced the diameter of curcumin-loaded PVP nanofiber and enhanced the release of curcumin from the fiber.

The Influence of Non-Ionic Surfactant on the Physical Characteristics of Curcumin-Loaded Nanofiber Manufactured by Electrospinning Method

Non-invasive administration of insulin is expected for better diabetes mellitus therapy. In this report, we developed intraoral preparation for insulin. Insulin was encapsulated into nanocarrier using self-assembly emulsification process. To increase lipophilicity of insulin, it was dispersed in phospholipid resulted in insulin-phospholipid solid dispersion. The microemulsion formula was established from our previous work which contained glyceryl monooleate (GMO), Tween 20, and polyethylene glycol (PEG 400) in a ratio of 1:8:1. To confirm the formation of insulin-phospholipid solid dispersion, PXRD, FTIR spectroscopy, and Raman spectroscopy were performed. Then, the microemulsion was evaluated for droplet size and distribution, zeta potential, entrapment efficiency, physical stability, and Raman spectroscopy. In addition, microemulsion with expected characteristic was evaluated for in vitro release, in vitro permeation, and in vivo activity. The droplets size of ∼100 nm with narrow distribution and positive charge of +0.56 mV were formed. The insulin encapsulated in the oil droplet was accounted of >90%. Water-soluble chitosan seems to be a promising film matrix polymer which also functioned as insulin release controller. Oral administration of insulin microemulsion to healthy Swiss-Webster mice showed hypoglycemic effect indicating the success of this protein against a harsh environment of the gastrointestinal tract. This effectiveness significantly increased by fourfold as compared to free insulin. Taken together, microemulsion seems to be a promising carrier for oral delivery of insulin.

/pdf/intraoral-film-containing-insulin-phospholipid-microemulsion-218hg4co7e.pdf

Intraoral Film Containing Insulin-Phospholipid Microemulsion: Formulation and In Vivo Hypoglycemic Activity Study

The great interest in exploring substances from plants for therapeutic purposes is growing nowadays and will be more stimulated in the future. This is due to the harmful effects of chemical compounds and toxicity challenges. As a growing trend, around 80% of people worldwide rely on herbal medicines for some aspect of their primary health care needs. Despite global concepts on safety use for such a wide range of medications, some of them are still lack in clinic evidence. Most bioactive compounds present in either crude extract, fraction, or even as a single isolate, which shows poor bioavailability and need for a large dose to demonstrate biological actions. Like synthetic drugs, the lack of clinical outcome upon using bioactive agents due to poor bioavailability is a key challenge in the drug delivery area. The biological barriers are identified as a main hindrance to the successful target of therapeutic agents. Hence, strategies to encounter them are challenging and remain a big issue to bring the active compounds to the correct site of action within the body. Nanotechnology-based drug formulation for bioactive compounds is one of the recent successful approaches in this field. Several patents and commercial FDA-approved products in the global market confirm the promise of this technology. This chapter discuss different types of nanocarriers, particularly lipid-based systems, nanosuspensions, and the safety consideration design as well as the biokinetics and the challenges for clinical translation in the future.

Heni Rachmawati

Papers

Bromelain Encapsulated in Self Assembly Nanoemulsion Exhibits Better Debridement Effect in Animal Model of Burned Skin

Formulation of tablet containing curcumin nanoemulsion

The Influence of Non-Ionic Surfactant on the Physical Characteristics of Curcumin-Loaded Nanofiber Manufactured by Electrospinning Method

Intraoral Film Containing Insulin-Phospholipid Microemulsion: Formulation and In Vivo Hypoglycemic Activity Study

Role of nanocarriers and their surface modification in targeting delivery of bioactive compounds