Identification of novel inhibitors of Plasmodium falciparum Heat Shock Protein 90 (HSP90) for the treatment of malaria

Onychomycosis is a fungal infection that affects the nail apparatus. Treating a nail infection like onychomycosis is challenging, as the human nail plate acts as a formidable barrier against all drug permeation. Available oral and topical treatments have several setbacks. Terbinafine hydrochloride (TBH), belonging to the allylamine class, is a broad spectrum antifungal that is mainly used for treatment of onychomycosis. Colloidal carriers have been investigated as drug delivery systems for the past 30 years in order to achieve specific drug targeting, facilitate the drug transfer through biological membranes, improve bioavailability, control release characteristics, and reduce or prevent side effects. This study aims to formulate TBH in a nanobased spanlastic vesicular carrier that enables and enhances the drug delivery through the nail. The nanovesicles were formulated by ethanol injection method, using either Span 60 or Span 65, together with Tween 80 or Sodium deoxycholate as an edge activator. A full factorial design was implemented to study the effect of different formulation and process variables on the prepared TBH-loaded spanlastic nanovesicles. TBH entrapment efficiency percentages, particle size diameter, percentage drug released after 2 hrs and 8 hrs were selected as dependent variables. Optimization was performed using Design-Expert software to obtain an optimized formulation with high entrapment efficiency (62.35±8.91%), average particle size of 438.45±70.5 nm, and 29.57±0.93% and 59.53±1.73% TBH released after 2 and 8 hrs, respectively. The optimized formula was further evaluated using differential scanning calorimetry and X-Ray diffraction after lyophilization and was also morphologically examined using transmission electron microscopy. An ex-vivo study was conducted to determine the permeation and retainment of the optimized formulation in a human cadaver nail plate and confocal laser scanning microscope was used to show the extent of formulation permeation. In conclusion, the results confirmed that spanlastics exhibit promising results for the trans-ungual delivery of Terbinafine Hydrochloride. Enantiospecific interactions of selected calcium channel antagonists with human cytochrome P450 CYP3A4 in vitro Kristyna Krasulova*, Pavel Anzenbacher, Zdenek Dvorak 1 Department of Pharmacology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic 2 Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Olomouc, Czech Republic Amlodipine, benidipine, felodipine and isradipine, members of a class of dihydropyridine calcium channel antagonists (CCBs), are widely prescribed drugs for the treatment of hypertension and ischemic heart disease. The key of their effect is their inhibition of entry of calcium ions via a subset of channels, thereby leading to impairment of contraction. All these chemical entities have an asymmetric carbon atom in their structures and they are used as racemic mixtures. In the most cases, calcium channel blockers are coadministered with other drugs. Therefore, the interactions between them and other drugs should be well explained. Single enantiomers may act differently in the body as a consequence of stereoselectivity of the interactions with three dimensional structures of proteins acting as enzymes, receptors or ion channels. These dihydropyridine calcium channel antagonists, which are mainly metabolized by CYP3A4, have been already described as possible inhibitors of human liver microsomal drugmetabolizing enzymes, cytochromes P450 (CYP). The aim of this study was to examine the difference in the inhibitory potency of individual enantiomers of selected CCBs towards catalytic activity of individual cytochromes P450, especially of the CYP3A4 enzyme. The 6βhydroxylation of testosterone, and midazolam 1 ́-hydroxylation, specific substrates for CYP 3A4, were used to evaluate the influence of (+)form and (-)form of individual drugs on the CYP 3A4 enzyme activity in human liver microsomes in vitro. There are in the literature data indicating the interactions of amlodipine, benidipine and felodipine with the CYP3A4 enzyme suggesting also the possibility of drug interactions in vivo [1, 2]. In the study presented here, the enantiospecific manner of the inhibitory effect of dilution series of selected CCBs enantiomers on the CYP3A4 activity is presented. The Ki values and IC50s have been calculated to evaluate the differences in the inhibition of CYP by individual enantiomers. Financial support from Czech Science Agency GACR 13-01809S project and IGA UPOL_LF_2015_004 is acknowledged. [1] Katoh M et al. Inhibition of human cytochrome P450 enzymes by 1,4-dihydropyridine calcium antagonists: prediction of in vivo drug-drug interactions. Eur J Pharmacol (2000)