Effect of Cryogrinding on Chemical Stability of the Sparingly Water-Soluble Drug Furosemide

Purpose To investigate the effect of cryogrinding on chemical stability of the diuretic agent furosemide and its mixtures with selected excipients. Methods Furosemide was ground at liquid nitrogen temperature for 30, 60, 120 and 180 min. Mixtures of furosemide-PVP and furosemide-inulin (1:1) were milled under cryogenic conditions. Materials were analyzed by XRD, UPLC, MS and NMR. Results Upon increasing the milling time, a significant build-up of an unidentified impurity 1, probably the main degradation product, was noticed. Cogrinding of furosemide with PVP and inulin worsened chemical stabilization of the pharmaceutical. The main degradation product formed upon cryomilling was subsequently identified as 4-chloro-5-sulfamoylanthranilic acid (CSA). Based on some theoretical considerations involving specific milling conditions, the milling intensity and an expected specific milling dose have been calculated. Results indicate that cryogenic grinding is capable to initiate mechanically induced decomposition of furosemide.Conclusions Cryogenic grinding can activate and accelerate not only structural changes (solid state amorphization) but also chemical decomposition of pharmaceuticals. A cryogenic milling device should be considered as a chemical reactor, where under favourable conditions chemical reactions could be mechanically initiated

Potential application enkephalns in diagnostics and treatment of various diseases

For the past few years enkephalins have been a center of appreciation and interest. Enkephalins were discovered in 1975 by Hughes, Kosterlitz and coworkers [1]. They can be described as short sequences of amino acids that are naturally produced in the central nervous system (CNS) in various glands throughout the body, such as the pituitary and adrenal glands [7, 9]. There were revealed two forms of enkephalins, one containing leucine, and the other containing methionine. Enkephalins are produced by the cleavage of a precursor protein called proenkephalin. From proenkephalin originate Met- and Leu-enkephalin, Met-enkephalin-Arg6-Gly7- -Leu8, Met-enkephalin-Arg6-Phe7 [1–3]. Enkephalins are involved in phenomena associated with modulated pain perception [13], regulation of memory and emotional conditions [21] and regulation of immunological system [29]. They also have an impact on the cardiovascular system [17], motility of the digestive system and metabolism of carbohydrates [8]. This article is a review of the current knowledge about enkephalins and their usage in the diagnostics and treatment of a variety of diseases: diseases/disorders of the central nervous system [21, 22], Parkinson’s disease [27], disease of the immune system [29], chronic pain [12], tumor diseases/cancer [33], heart and cardiovascular diseases [19] and inflammatory bowel disease [23]

In vitro activity of the lipopeptide PAL-Lys-Lys-NH2, alone and in combination with antifungal agents, against clinica isolates of Candida spp

2010 Nov 3. [Epub ahead of print

Lipopeptide Laur-CKK-NH2 dimer preserves daptomycin susceptibility and enhances its activity against Enterococcus faecalis

An experimental study was performed to evaluate both in vitro and in vivo the kind of interaction between the Laur-CKK-NH2 dimer and daptomycin using two Enterococcus faecalis strains with different patterns of susceptibilities. We evaluated whether selection for daptomycin-resistant E. faecalis could be prevented in vitro by combining daptomycin with the Laur-CKK-NH2 dimer. The strains were serially exposed in broth to 2-fold stepwise increasing concentrations of daptomycin alone or in combination with a fixed concentration (0.25×MIC) of the Laur-CKK-NH2 dimer. We also performed an in vitro synergy study. For in vivo studies, a mouse model of enterococcal sepsis was used. In vitro experiments: exposure to daptomycin alone gradually selected for enterococci with increased MICs; and the Laur-CKK-NH2 dimer showed a positive interaction with daptomycin and was able to prevent the resistance. In vivo experiments: the main outcome measures were lethality and quantitative blood cultures; and the Laur-CKK-NH2 dimer combined with daptomycin exhibited the highest efficacy for all main outcome measurements. These results highlight the potential usefulness of combining daptomycin with the Laur-CKK-NH2 dimer. The combination provides a future therapeutic alternative for the treatment of enterococcal severe infections

Efficacy of cathelicidin ll-37 in an mrsa wound infection mouse model

Background: LL-37 is the only human antimicrobial peptide that belongs to the cathelici-dins. The aim of the study was to evaluate the efficacy of LL-37 in the management of MRSA-in-fected surgical wounds in mice. Methods: A wound on the back of adult male BALB/c mice was made and inoculated with Staphylococcus aureus. Two control groups were formed (uninfected and not treated, C0; infected and not treated, C1) and six contaminated groups were treated, respec-tively, with: teicoplanin, LL-37, given topically and /or systemically. Histological examination of VEGF expression and micro-vessel density, and bacterial cultures of wound tissues, were per-formed. Results: Histological examination of wounds in the group treated with topical and intra-peritoneal LL-37 showed increased re-epithelialization, formation of the granulation tissue, collagen organization, and angiogenesis. Conclusions: Based on the mode of action, LL-37 has a potential future role in the management of infected wounds

Copper binding to chicken and human prion protein amylodogenic regions: differences and similarities revealed by Ni2+ as a diamagnetic probe

Both human (h) and chicken (Ch) prion proteins (PrP) bind copper ions within the so called ‘‘tandem repeat” N-terminal region. Outside this region, hPrP possesses two additional copper binding sites, localized at His-96 and His-111 in the so called ‘‘amylodogenic” or neurotoxic region (residues 91–126). Also ChPrP possesses a similar region (ChPrP105140) containing two His (His-110 and His-124) and an identical hydrophobic tail of 15 amino acids rich in Ala and Gly. The copper binding abilities within such region of ChPrP were investigated by NMR, CD and potentiometry using Ni2+ as diamagnetic probe. The formation of diamagnetic metal complexes allowed to monitor the chemical shift and signal intensity variations and to determine the structural and kinetic features of the His-110 and His-124 metal binding sites. Finally a comparison between the hPrP and ChPrP metal binding abilities was performed. We found that the two prion proteins exhibited different copper and nickel preferences with the favoured metal binding sites localized at opposite His: His-110 for ChPrP, and His-111 for hPrP