Optimizing Nanosuspension Drug Release and Wound Healing Using a Design of Experiments Approach: Improving the Drug Delivery Potential of NDH-4338 for Treating Chemical Burns.

NDH-4338 is a highly lipophilic prodrug comprising indomethacin and an acetylcholinesterase inhibitor. A design of experiments approach was used to synthesize, characterize, and evaluate the wound healing efficacy of optimized NDH-4338 nanosuspensions against nitrogen mustard-induced skin injury. Nanosuspensions were prepared by sonoprecipitation in the presence of a Vitamin E TPGS aqueous stabilizer solution.

Derivatives of 1,2,4-triazole imines acting as dual iNOS and tumor cell growth inhibitors.

A set of 4-(R-imino)-3-mercapto-5-(R)-4H-1,2,4-triazoles derivatives were synthesized, characterized and evaluated for their ability to inhibit nitric oxide (NO) production in PAM212 mouse keratinocytes, which led to the discovery and the subsequent evaluation of their growth inhibitory cytotoxic potency toward that same mouse cell line together with a number of human cells lines (PC3, HT-29 and HeLa). Some limited SAR could be established for both NO production inhibition potency and growth inhibition cytotoxicity. Noticeably, the compounds designed to be nitrofurantoin mimics were the most potent anti-neoplastic agents.

Antioxidant/stress response in mouse epidermis following exposure to nitrogen mustard.

Nitrogen mustard (NM) is a highly reactive bifunctional alkylating agent that induces inflammation, edema and blistering in skin. An important mechanism mediating the action of NM and related mustards is oxidative stress. In these studies a modified murine patch-test model was used to analyze DNA damage and the antioxidant/stress response following NM exposure in isolated epidermis.

Phototoxicity of 7-oxycoumarins with keratinocytes in culture.

Seventy-one 7-oxycoumarins, 66 synthesized and 5 commercially sourced, were tested for their ability to inhibit growth in murine PAM212 keratinocytes. Forty-nine compounds from the library demonstrated light-induced lethality. None was toxic in the absence of UVA light.

Synthetically modified methoxsalen for enhanced cytotoxicity in light and dark reactions.

Linear furocoumarins, also known as psoralens, are clinically useful photo-activated pharmaceuticals employed to address hyperproliferative skin diseases. Seven diverse cytotoxic pharmacophores have been synthetically attached to 8-methoxypsoralen via a 5-amino functionality. The resulting unique set of compounds was evaluated for dark and light toxicity against PAM212 keratinocytes in culture.

SYNTHESIS AND EVALUATION OF WATER-SOLUBLE DIMETHYLAMINOETHYL ETHERS OF METHOXSALEN FOR PROLIFERATIVE SKIN DISORDERS.

The natural product 8-methoxypsoralen (methoxsalen or 8-MOP) in combination with long wavelength ultraviolet light (UVA, 320-400 nm), also referred to as PUVA therapy, is used for the treatment of cutaneous proliferative disorders including psoriasis, vitiligo and mycosis fungoides. The use of 8-MOP () is limited by its poor water solubility and there remains a need to develop more water-soluble psoralens to enhance bioavailability following oral administration of the drug. In the present studies a water-soluble dimethylaminoethyl ether analog of 8-MOP was synthesized and analyzed for biological activity.

Identification of a Pyranocoumarin Photosensitizer that is a Potent Inhibitor of Keratinocyte Growth.

Photosensitizers are used in the treatment of epidermal proliferation and differentiation disorders such as psoriasis and vitiligo. In these studies, a ring-expanded carbon homolog of the linear psoralen (furo[3,2-g]benzopyran-7-one) class of photosensitizers, 4,10-dimethyl-2H,8H-benzo[1,2-b:5,4-b']dipyran-2-one (NDH2476), was synthesized and analyzed for biological activity. Following activation by ultraviolet light (UVA, 320-400 nm), NDH2476 was found to be a potent inhibitor of keratinocyte growth (IC  = 9 nm).

Sulfur mustard induced mast cell degranulation in mouse skin is inhibited by a novel anti-inflammatory and anticholinergic bifunctional prodrug.

Sulfur mustard (SM, bis(2-chloroethyl sulfide) is a potent vesicating agent known to cause skin inflammation, necrosis and blistering. Evidence suggests that inflammatory cells and mediators that they generate are important in the pathogenic responses to SM. In the present studies we investigated the role of mast cells in SM-induced skin injury using a murine vapor cup exposure model.

Multi-inhibitor prodrug constructs for simultaneous delivery of anti-inflammatory agents to mustard-induced skin injury.

The molecular pathology of sulfur mustard injury is complex, with at least nine inflammation-related enzymes and receptors upregulated in the zone of the insult. A new approach wherein inhibitors of these targets have been linked by hydrolyzable bonds, either one to one or via separate preattachment to a carrier molecule, has been shown to significantly enhance the therapeutic response compared with the individual agents. This article reviews the published work of the authors in this drug development domain over the last 8 years.

Mitigation of nitrogen mustard mediated skin injury by a novel indomethacin bifunctional prodrug.

Nitrogen mustard (NM) is a bifunctional alkylating agent that is highly reactive in the skin causing extensive tissue damage and blistering. In the present studies, a modified cutaneous murine patch model was developed to characterize NM-induced injury and to evaluate the efficacy of an indomethacin pro-drug in mitigating toxicity. NM (20μmol) or vehicle control was applied onto 6mm glass microfiber filters affixed to the shaved dorsal skin of CD-1 mice for 6min.

Mustard vesicants alter expression of the endocannabinoid system in mouse skin.

Vesicants including sulfur mustard (SM) and nitrogen mustard (NM) are bifunctional alkylating agents that cause skin inflammation, edema and blistering. This is associated with alterations in keratinocyte growth and differentiation. Endogenous cannabinoids, including N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoyl glycerol (2-AG), are important in regulating inflammation, keratinocyte proliferation and wound healing.

ADAM17 Inhibitors Attenuate Corneal Epithelial Detachment Induced by Mustard Exposure.

Purpose: Sulfur mustard, nitrogen mustard (NM), and 2-chloroethyl ethyl sulfide all cause corneal injury with epithelial-stromal separation, differing only by degree. Injury can resolve in a few weeks or develop into chronic corneal problems. These vesicants induce microbullae at the epithelial-stromal junction, which is partially caused by cleavage of transmembranous hemidesmosomal collagen XVII, a component anchoring the epithelium to the stroma.

Selective Targeting of Heme Protein in Cytochrome P450 and Nitric Oxide Synthase by Diphenyleneiodonium.

Cytochrome P450 (CYP) enzymes mediate mixed-function oxidation reactions important in drug metabolism. The aromatic heterocyclic cation, diphenyleneiodonium (DPI), binds flavin in cytochrome P450 reductase and inhibits CYP-mediated activity. DPI also inhibits CYP by directly interacting with heme.

Ethynylphenyl carbonates and carbamates as dual-action acetylcholinesterase inhibitors and anti-inflammatory agents.

Novel ethynylphenyl carbonates and carbamates containing carbon- and silicon-based choline mimics were synthesized from their respective phenol and aniline precursors and screened for anticholinesterase and anti-inflammatory activities. All molecules were micromolar inhibitors of acetylcholinesterase (AChE), with IC50s of 28-86 μM; the carbamates were two-fold more potent than the carbonates. Two of the most potent AChE inhibitors suppressed 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation by 40%.

Sulfa drugs inhibit sepiapterin reduction and chemical redox cycling by sepiapterin reductase.

Sepiapterin reductase (SPR) catalyzes the reduction of sepiapterin to dihydrobiopterin (BH2), the precursor for tetrahydrobiopterin (BH4), a cofactor critical for nitric oxide biosynthesis and alkylglycerol and aromatic amino acid metabolism. SPR also mediates chemical redox cycling, catalyzing one-electron reduction of redox-active chemicals, including quinones and bipyridinium herbicides (e.g.

-NITRO--SUBSTITUTED GUANIDINES: A SIMPLE CLASS OF NITRIC OXIDE SYNTHASE INHIBITORS.

A series of N-nitro-N-substituted guanidines has been prepared as potential inhibitors of the human Nitric Oxide Synthase (NOS) isoforms. The reported utility of aminoguanidine and nitroarginine in iNOS inhibition points to a potential similar utility for analogs of nitro-guanidine. The compound library was tested against the three isoforms of Nitric Oxide Synthase (eNOS, iNOS and nNOS).

Therapeutic potential of a non-steroidal bifunctional anti-inflammatory and anti-cholinergic agent against skin injury induced by sulfur mustard.

Sulfur mustard (bis(2-chloroethyl) sulfide, SM) is a highly reactive bifunctional alkylating agent inducing edema, inflammation, and the formation of fluid-filled blisters in the skin. Medical countermeasures against SM-induced cutaneous injury have yet to be established. In the present studies, we tested a novel, bifunctional anti-inflammatory prodrug (NDH 4338) designed to target cyclooxygenase 2 (COX2), an enzyme that generates inflammatory eicosanoids, and acetylcholinesterase, an enzyme mediating activation of cholinergic inflammatory pathways in a model of SM-induced skin injury.

Pharmacokinetics and metabolism of SRX246: a potent and selective vasopressin 1a antagonist.

SRX246 is a potent, highly selective, orally bioavailable vasopressin 1a receptor antagonist that represents a novel mechanism of action for the treatment of mood disorders. The compound previously showed efficacy in animal models of mood disorders and excellent safety and tolerability in healthy volunteers in phase I clinical trials. In this study, SRX246 was further characterized in rats and dogs.

Back-scattering interferometry: an ultrasensitive method for the unperturbed detection of acetylcholinesterase-inhibitor interactions.

A series of inhibitors of acetylcholinesterase (AChE) have been screened by back-scattering interferometry (BSI). Enzyme levels as low as 100 pM (22,000 molecules of AChE) can be detected. This method can be used to screen for mixed AChE inhibitors, agents that have shown high efficacy against Alzheimer's disease, by detecting dual-binding interactions.

Synthesis and evaluation of potent and selective human V1a receptor antagonists as potential ligands for PET or SPECT imaging.

SRX246 is a potent, highly selective human vasopressin V1a antagonist that crosses the blood-brain barrier in rats. CNS penetration makes SRX246 an ideal candidate for potential radiolabeling and use in visualization and characterization of the role of the V1a receptor in multiple stress-related disorders. Before radiolabeling studies, cold reference analogs of SRX246 were prepared.

Investigation of anticholinergic and non-steroidal anti-inflammatory prodrugs which reduce chemically induced skin inflammation.

As part of a continuous effort to develop efficient counter measures against sulfur mustard injuries, several unique NSAID prodrugs have been developed and screened for anti-inflammatory properties. Presented herein are three classes of prodrugs which dually target inflammation and cholinergic dysfunction. Compounds 1-28 contain common NSAIDs linked either to choline bioisosteres or to structural analogs of acetylcholinesterase (AChE) inhibitors.

Doxycycline hydrogels as a potential therapy for ocular vesicant injury.

Purpose: The goals of this study were (1) to compare the injury at the basement membrane zone (BMZ) of rabbit corneal organ cultures exposed to half mustard (2 chloroethyl ethyl sulfide, CEES) and nitrogen mustard with that of in vivo rabbit eyes exposed to sulfur mustard (SM); (2) to test the efficacy of 4 tetracycline derivatives in attenuating vesicant-induced BMZ disruption in the 24-h period postexposure; and (3) to use the most effective tetracycline derivative to compare the improvement of injury when the drug is delivered as drops or hydrogels to eyes exposed in vivo to SM.

Methods: Histological analysis of hematoxylin and eosin–stained sections was performed; the ultrastructure of the corneal BMZ was evaluated by transmission electron microscopy; matrix metalloproteinase-9 was assessed by immunofluorescence; doxycycline as drops or a hydrogel was applied daily for 28 days to eyes exposed in vivo to SM. Corneal edema was assessed by pachymetry and the extent of neovascularization was graded by length of longest vessel in each quadrant.

Oxidants and antioxidants in sulfur mustard-induced injury.

Sulfur mustard (SM) is a chemical weapon that targets the skin, eyes, and lung. It was first employed during World War I and it remains a significant military and civilian threat. As a bifunctional alkylating agent, SM reacts with a variety of macromolecules in target tissues including nucleic acids, proteins and lipids, as well as small molecular weight metabolites such as glutathione.

Peripheral site acetylcholinesterase inhibitors targeting both inflammation and cholinergic dysfunction.

The design and study of two classes of noncompetitive acetylcholinesterase inhibitors (AChEIs) which also function as NSAID prodrugs are reported. The most potent AChEIs disclosed contain an aromatic alkyl-aryl linker between an NSAID and a lipophilic choline mimic and they inhibit acetylcholinesterase (AChE) in the submicromolar range. These agents have the therapeutic potential to dually target inflammation by releasing an NSAID in vivo and activating the cholinergic anti-inflammatory pathway via cholinergic up-regulation.

Mechanisms mediating the vesicant actions of sulfur mustard after cutaneous exposure.

Sulfur mustard (SM), a chemical weapon first employed during World War I, targets the skin, eyes, and lung. It remains a significant military and civilian threat. The characteristic response of human skin to SM involves erythema of delayed onset, followed by edema with inflammatory cell infiltration, the appearance of large blisters in the affected area, and a prolonged healing period.