Preparation and evaluation of topical microemulsion system containing metronidazole for remission in rosacea

The aim of this study was to prepare a topical water-in-oil type microemulsion containing metronidazole and to compare its effectiveness with a commercial gel product in the treatment of rosacea. A pseudo-ternary phase diagram (K(m)=2:1) was constructed using lecithin/butanol/isopropyl myristate/water. The microemulsion was chosen from the microemulsion region in the phase diagram. The formulation was a water-in-oil type microemulsion (droplet size: 11.6 nm, viscosity: 457.3 mPa·s, conductivity: 1.5 μs/cm, turbidity: 6.89 NTU) and the addition of the metronidazole did not alter the properties of the system. The release experiment showed that the release rate of metronidazole from the commercial gel product was higher than that of the microemulsion. Stability experiments showed that the metronidazole microemulsion remained stable for at least 6 months; none of the characteristic properties of the microemulsion had changed, the system retained its clarity and there was no sign that crystallization of metronidazole has occurred. Microemulsion was compared to a gel product in a randomized, double-blind, baseline-controlled, split-face clinical trial for the treatment of patients. After the 6-week treatment period there was a statistically significant difference in reduction of the main symptoms of rosacea. Of the patients treated with the microemulsion, 17% experienced complete relief from inflammatory lesions, and 50% from erythema. The microemulsion resulted in complete relief in 38% of the patients with telangiectasia while the commercial product did not provide any relief of telangiectasia symptoms. In conclusion, the microemulsion containing metronidazole was found to be more effective in reducing the symptoms of rosacea compared to the commercial gel product.     

Variables that influence cellular uptake and cytotoxic/cytoprotective effects of macrocyclic iron complexes

Determination of the cellular uptake of macrocyclic iron(III) complexes by a facile method, accompanied by cell viability tests under both basal and induced oxidative stress, demonstrates that protection against intracellular oxidative stress requires reasonably high internalization and favorable anti/prooxidant profiles. Of the four tested complexes, only amphipolar iron(III) corrole met these criteria.     

Catalytic behavior of melamine glyoxal resin towards consecutive oxidation and oxy-Michael addition

Synthesis of melamine glyoxal resin involves a catalyst-free, one pot reaction between melamine and glyoxal in DMF. The synthesized resins have a similar morphological arrangement to that of layered materials as depicted by their XRD pattern and Raman spectra. The catalytic behavior of melamine glyoxal resin (MGR) have been studied in allylic oxidation of cyclohexene and simultaneous Michael addition. The MGR/solvent/O₂ oxidant system can be regarded as a metal-free, additive-free, cost-effective and environmentally benign catalytic system. The oxidative behavior of MGR is attributed to its ability to generate in situ organic peroxide species during the course of reaction. Generation of peroxide species is confirmed by the KI/starch test and further confirmed by the complete suppression effect of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) over oxidation. The activity for Michael addition can be attributed to the presence of a higher content of nitrogen atoms, which serves as the active site. In oxidation, 28.1% conversion of cyclohexene with 37.19 and 62.81% selectivities for cyclohexenol and cyclohexenone were observed, respectively. In consecutive oxidation and oxy-Michael addition, 31.5% conversion of cyclohexene was observed with selectivities of 61.6% for cyclohexenone and 38.4% for alkoxy product.     

Glycerol as solvent and hydrogen donor in transfer hydrogenation-dehydrogenation reactions

Glycerol is employed successfully as a green solvent and hydrogen donor in catalytic transfer hydrogenation-dehydrogenation reactions. The glycerol donates hydrogen to various unsaturated organic compounds under mild reaction conditions and as a solvent, allows easy separation of products and catalyst recycling.     

The Newton Bracketing method for the minimization of convex functions subject to affine constraints

The Newton Bracketing method [Y. Levin, A. Ben-Israel, The Newton Bracketing method for convex minimization, Comput. Optimiz. Appl. 21 (2002) 213-229] for the minimization of convex functions f:Rⁿ→R is extended to affinely constrained convex minimization problems. The results are illustrated for affinely constrained Fermat-Weber location problems.     

Constrained maximization of posynomials by geometric programming

Geometric programming is extended and applied to maximize a posynomial subject to posynomial constraints.The contribution of the senior author is part of a Ph.D. Thesis in Industrial Engineering, Northwestern University, 1969. This research was partly supported by the National Science Foundation, Project No. GP-13546. The authors are grateful to Professor R. J. Duffin for his many helpful comments and suggestions.     

Linear inequalities,mathematical programming and matrix theory

A survey is made of solvability theory for systems of complex linear inequalities.This theory is applied to complex mathematical programming and stability and inertia theorems in matrix theory.This paper was presented at the 7th Mathematical Programming Symposium 1970, The Hague, The Netherlands.     

Approximate methods for convex minimization problems with series–parallel structure

Consider a problem of minimizing a separable, strictly convex, monotone and differentiable function on a convex polyhedron generated by a system of m linear inequalities. The problem has a series–parallel structure, with the variables divided serially into n disjoint subsets, whose elements are considered in parallel. This special structure is exploited in two algorithms proposed here for the approximate solution of the problem. The first algorithm solves at most min{m, ν − n + 1} subproblems; each subproblem has exactly one equality constraint and at most n variables. The second algorithm solves a dynamically generated sequence of subproblems; each subproblem has at most ν − n + 1 equality constraints, where ν is the total number of variables. To solve these subproblems both algorithms use the authors’ Projected Newton Bracketing method for linearly constrained convex minimization, in conjunction with the steepest descent method. We report the results of numerical experiments for both algorithms.     

Chemically Crosslinked Polysaccharide of the Red Microalga Rhodella Reticulata - An Ion Exchanger for Toxic Metal Ions 1

The structure and physicochemical properties of the sulfated polysaccharides that encapsulate cells of the red microalgae have been studied in our laboratory for a number of years with the aim of evaluating their potential applications.^2-6 Exploitation of the charged groups of these heteropolymers as chelating agents could provide an environmentally friendly means of disposing of toxic metals in industrial wastes. Ion exchangers and affinity absorbents may be prepared by crosslinking polysaccharides with epichlorhydrin, for example, mucopolysaccharides can bind polyvalent ions.^7-9

     

Diastereomerically-specific zirconium complexes of chiral salan ligands: isospecific polymerization of 1-hexene and 4-methyl-1-pentene and cyclopolymerization of 1,5-hexadiene

Chiral Salan ligands were found to wrap in a highly diastereoselective manner around zirconium leading to C2-symmetric complexes of predetermined chirality at the metal. These complexes led to active polymerization of higher olefins, their activity and isospecific induction depending on the nature of the phenolate substituents.