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Glutathione disulfide (GSSG) is the oxidized form of glutathione (GSH). GSH is a tripeptide present in the biological system in mM concentration and is the major antioxidant in the body. An increase in GSSG reflects an increase in intracellular oxidative stress and is associated with disease sates. The increase has also been demonstrated to lead to an increase in protein S-glutathionylation that can affect the structure and function of proteins. Protein S-glutathionylation serves as a regulatory mechanism during cellular oxidative stress. Though GSSG is commercially available, its roles in various GSSG-associated normal/abnormal physiological functions have not been fully delineated due to the reason that GSSG is not cell membrane permeable and a lack of method to specifically increase GSSG in cells. We have developed cationic liposomes that can effectively deliver GSSG into cells. Various concentrations of GSSG liposomes can be conveniently prepared. At 1 mg/mL, the GSSG liposomes effectively increased intracellular GSSG by 27.1±6.9 folds (n=3) in 4 h and led to a significant increase in protein S-glutathionylation confirming that the increased GSSG is functionally effective. The Trypan blue assay demonstrated that GSSG liposomes were not cytotoxic; the cell viability was greater than 95% after cells were treated with the GSSG liposomes for 4 h. A stability study showed that the dry form of the GSSG liposomes were stable for at least 70 days when stored at −80 °C. Our data demonstrate that the GSSG liposomes can be a valuable tool in studying GSSG-associated physiological/pathological functions., Highlights • Glutathione disulfide (GSSG) liposomes were developed to deliver GSSG into cells. • The GSSG liposomes effectively increased intracellular GSSG by 27.1±6.9 folds. • The delivered GSSG is confirmed to be functionally effective through protein S-glutathionylation.

Majority of breast cancers originate from epithelial cells in the duct and lobules in the breast. Current systemic treatments for breast cancer are associated with significant systemic side effects, thus warranting localized drug delivery approaches. The aim of this study was to investigate the influence of hydroalcoholic vehicle on topical delivery of 4-hydroxy tamoxifen (4-HT) through the mammary papilla (nipple). The in vitro permeability of 4-HT through porcine mammary papilla was studied using different hydroalcoholic vehicles (0, 33.33, and 66.66% alcohol). Nile red was used as a model lipophilic dye to characterize the drug transport pathway in the mammary papilla. The penetration of 4-HT through the mammary papilla increased with increase in alcohol concentration in the vehicle. The solubility of 4-HT was enhanced by increasing alcohol concentration in the vehicle. On the other hand, the epidermis/vehicle partition coefficient decreased with increase in alcohol concentration. The mammary papilla served as a depot and slowly released 4-HT into the receptor medium. Highest drug penetration was observed with saturated drug solution in 66.66% alcohol, and 4-HT levels were comparable to IC50 value of 4-HT. Results from this study demonstrate the possibility of using mammary papilla as a potential route for direct delivery of 4-HT to the breast.

The main objective of the present study was to investigate the influence of various formulation parameters on the preparation of zein nanoparticles. 6,7-dihydroxycoumarin (DHC) was used as a model hydrophobic compound. The influence of pH of the aqueous phase, buffer type, ionic strength, surfactant, and zein concentration on particle size, polydispersity index, and zeta potential of DHC-loaded zein nanoparticles were studied. Smaller nanoparticles were formed when the pH was close to the isoelectric point of zein. DHC-loaded zein nanoparticles prepared using citrate buffer (pH 7.4) was better than phosphate buffer in preventing particle aggregation during lyophilization. The ionic strength did not have a significant influence on the particle size of DHC-loaded zein nanoparticles. A combination of Pluronic F68 and lecithin in 2:1 ratio stabilized the zein nanoparticles. An increase in zein concentration led to increase in particle size of DHC-loaded zein nanoparticles. The use of optimal conditions produced DHC-loaded nanoparticles of 256 ± 30 nm and an encapsulation efficiency of 78 ± 7%. Overall, the study demonstrated the optimal conditions to prepare zein nanoparticles for drug encapsulation.

Purpose: Honokiol, a plant lignan isolated and purified from Magonila Officinalis has been shown to have chemopreventive effects in chemically induced and UV-B induced skin tumor development in SKH-1 mice. However poor solubility of honokiol greatly limits its clinical application. The key objectives of the present investigation are to improve the solubility and stability of honokiol by encapsulating in nanostructured lipid nanoparticles. Methods: Honokiol was incorporated into nanostructured lipid nanoparticles and cream using hot homogenization method. Compritol 888 ATO, Precirol ATO 5, and miglyol 812 as lipid matrices and poloxamer 188 as emulsifier. Lipid nanoparticles were characterized for size, zeta potential, shape and morphology using photon correlation spectroscopy (PCS) and atomic force microscopy (AFM). Honokiol was quantified by isocratic HPLC method using mobile phase of 60:40 (%v/v, acetonitrile:water) at a flow rate of 1 ml/min at a wavelength of 254 nm. Permeation studies were carried out using porcine dermatome skin in Franz diffusion cell. Honokiol concentration corresponding to 0.5 mg/ml in sesame oil, cream and lipid nanoparticles was dispersed in PBS pH 7.4. Permeation studies were performed till 24hrs; the samples (200 µl) were withdrawn at regular time intervals and replaced with fresh medium. Amount of honokiol permeated across porcine skin was quantified using HPLC method. Stability of cream and lipid nanoparticle formulations was studied at 30° C and 65 % relative humidity in a stability chamber for one month. Results: The size of the optimized honokiol loaded lipid nanoparticles was 145±7 nm with a polydispersity index of 0.24±0.02. The zeta potential and encapsulation efficiency was 0.34±0.02 mV and 97±2 %. The particle size of lipid nanoparticles measured in AFM was very close to size measured by PCS. In case of precirol cream, particle size was more than 20 µm with drug content of 89±5 %. Honokiol loaded nanostructured lipid nanoparticles, and cream were stable for about 30 days without any significant changes in particle size, and drug content at 30° C and 65 % relative humidity. Skin treated with honokiol entrapped in nanoparticles and cream has shown more retention of honokiol in the skin compared to plain honokiol in sesame oil. Proposed lipid cream and nanoparticles formulation has shown effective skin penetration of honkiol. From the data it is evident that nanoparticles has shown higher amount of honokiol in skin compared to cream formulation. Conclusions: Preliminary results of this study have shown the potential of lipid based formulations for topical delivery of honokiol. Chemopreventive potential and efficacy of honokiol encapsulated in lipid based formulations will be evaluated in UV-B induced skin cancer model. Acknowledgements: Supported by Translational Cancer Research Center funded by the South Dakota Governor's Office of Economic Development. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5709. doi:1538-7445.AM2012-5709

Skin cancer is the most prevalent of all cancers and its incidence is expected to increase substantially. UVB is major etiologic factor in the skin cancer development. Honokiol, a plant ligan isolated from bark and seed cones of Magnolia officinalis, has been shown to have chemopreventive effects on UVB-induced skin cancer development in our laboratory. The objectives of this investigation are to study chemopreventive effects of dose response of honokiol on UVB-induced skin tumor development in SKH-1mice and to prepare topical formulations of honokiol that deliver effective concentration of drug locally. Female SKH-1 mice were divided into 4 groups. Group 1 received acetone one hour before UVB treatment; Group 2, 3 and 4 received honokiol (0.2 ml of 30, 45 and 60 μg in acetone, topical) before each UVB treatment. Mice were treated with UVB dose of 30 mJ/cm2/day for 25 weeks. Tumor counts and group weights were taken weekly. Honokiol pretreated groups resulted in 36-78% reduction in tumor multiplicity compared to control. Honokiol pretreatment (60 μg) decreased tumor incidence by 40 %. Topical formulation of honokiol gel was prepared by using carbomer 940 as base and propylene glycol as penetration enhancer. Drug content and content uniformity were determined. Release studies and permeation studies were studied in detail. This study is supported by Translational Cancer Research Center funded as 2010 Research Initiative Center by the State of South Dakota Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4620. doi:10.1158/1538-7445.AM2011-4620

The purpose of this investigation is to characterize nevirapine from commercial samples and samples crystallized from different solvents under various conditions. The solid-state behavior of nevirapine samples was investigated using a variety of complementary techniques such as microscopy (optical, polarized, hot stage microscopy), differential scanning calorimeter, thermogravimetric analysis, Fourier transform infrared spectroscopy and powder X-ray diffractometry. The commercial samples of nevirapine had the same polymorphic crystalline form with an anhedral crystal habit. Intrinsic dissolution of nevirapine was similar for both the commercial batches. Powder dissolution showed pH dependency, with maximum dissolution in acidic pH and there was no significant effect of particle size. The samples recrystallized from different solvent systems with varying polarity yielded different crystal habits. Stirring and degrees of supersaturation influenced the size and shape of the crystals. The recrystallized samples did not produce any new polymorphic form, but weak solvates with varying crystal habit were produced. Recrystallized samples showed differences in the x-ray diffractograms. However, all the samples had the same internal crystal lattice as revealed from their similar melting points and heat of fusion. The intrinsic dissolution rate of recrystallized samples was lower than the commercial sample. It was found that the compression pressure resulted in desolvation and partial conversion of the crystal form. After compression, the recrystallized samples showed similar x-ray diffractograms to the commercial sample. Amorphous form showed slightly higher aqueous solubility than the commercial crystalline form.