[Audit of sterilization practices in two Tunisian hospitals: current situation and perspectives]. / Audit des pratiques de stérilization dans deux établissements hospitaliers Tunisiens: Etat des lieux et perspectives.

BACKGROUND: In most Tunisian hospitals, medical devices (MD) are sterilized at surgical or medicine departments. AIM: to overview during one month the practice of sterilization. aterial METHODS: An audit of practices through direct observation was carried out at the neonatology and gynaecology departments at the Maternity and Neonatology Center of Tunis and the surgical department at the Salah Azaïz Institute. An assessment grid has been defined and the non-compliance rates have been calculated. A score has been drawn for four evaluation categories of MD treatment. 123 criteria were assessed. RESULTS: The level of non-compliance ranges from 53% to 62% depending on the department. Scores interpretation underlines that the present situation is behind the required level of safety. Traceability stands at the most critical position. Staff and environment safety present scores of 26/54 and 28/62 respectively for the Maternity and Neonatology Center of Tunis and the Salah Azaïz Institute. The less critical situation is that of patient safety, even if it is far below the expected level. CONCLUSION: This audit has highlighted major malfunctions in the sterilization process. This is related to the absence of a strict regulation. A corrective action plan has been implemented for the short, medium and long terms.

Impact of crystal polymorphism of rifaximin on dissolution behavior.

Introduction: Rifaximin is an intestinal antiseptic which has five (pseudo) polymorphs α, ß, γ, δ and ε. These last (pseudo)polymorphs have different physicochemical properties. The objective of the study is to assess the impact of rifaximin polymorphism on its dissolution rate which could affect its bioavailability. Material and methods: The analytical validation of dissolution assay method by UV-Visible spectrophotometry was carried out according to ICH Q2. The physicochemical characterization (solubility test, FTIR, DSC, XRD) was carried out on four active pharmaceutical ingredient (MP1, MP2, MP3, MP4). MP1 and MP2 were used by the manufacturer of generic brand 1 (G1) and MP3 and MP4 were used by the manufacturer of generic brand 2 (G2). The comparative in-vitro dissolution study was carried out on the leader brand (P), G1 and G2. Results: The four MPs were analyzed by XRD. The results of analysis showed that MP1 and MP4 were a mixture of α form and amorphous form. MP2 had an amorphous form and MP3 had a crystalline form ß. The spectra of FTIR showed that the four MP had characteristics bands of rifaximin in the domain 4000-400 cm-1. The differences between the spectra of the four MPs were observed among the amorphous form (MP2), around the region 1800 to 1820 cm-1 which is attributed to the vibration of the CO group. An additional difference observed among the amorphous form (MP2) is around the region 1400 cm-1 which is attributed to the banding OH. The thermograms of MP1, MP2 and MP4 showed endothermic peaks which are probably attributed to the departure of water which indicate that MP1, MP2 and MP4 are pseudopolymoph (hydrate). For the four MPs, probably the melting points are interrupted by the phenomenon of phase transformations (Crystallization) which are reflected by exothermic peaks around 200°C-250 °C.Our results showed that the crystalline polymorphism of rifaximin influences its solubility. According to the results of the solubility test, the ß crystal form of rifaximin (MP3) had the lowest solubility (3.47 µg/ml). MP2 had the highest solubility (8.35 µg/ml) and MP1 and MP4 had intermediate solubilities (5.47 µg/ml and 6.74 µg/ml). Comparative in vitro dissolution results showed that the dissolution profile of P was not similar to that of G1 and G2 (% dissolution (P)30min = 60%; % dissolution (G1) 30 min = 100% and % dissolution (G2) 30 min = 115%; f1(P versus G1) = 44; f1(P versus G2) = 61) in M1, while G1 and G2 had comparatively similar dissolution profiles (% dissolution (G1) 30 min = 100%; % dissolution (G1) 30 min = 110%; f1 (G1 versus G2) = 14) in M1. Conclusion: This study highlighted the impact of rifaximin polymorphism on its physico-chemical properties (crystal structure, thermal behavior, solubility) and on its dissolution behavior which could affect the rifaximin bioavailability.

Application of Factorial and Doehlert Designs for the Optimization of the Simultaneous Separation and Determination of Antimigraine Drugs in Pharmaceutical Formulations by RP-HPLC-UV.

A sensitive, precise, accurate, and specific isocratic reversed-phase high-performance liquid chromatographic (RP-HPLC) method for the simultaneous separation and determination of zolmitriptan, naratriptan, dihydroergotamine, ketotifen, and pizotifen in pharmaceutical formulations has been developed and validated. An experimental design was applied for the optimization of the chromatographic parameters. A two-level full factorial 2 k was used for studying the interaction between the variables to be optimized: the percentage of acetonitrile in the mobile phase, mobile-phase pH, nature of the buffer, and column oven temperature. The most significant parameters are the percentage of acetonitrile and the mobile-phase pH. These significant parameters were optimized using the Doehlert matrix. The optimum separation was achieved by means of a Waters XBridge C18 column (250 mm × 4.6 mm, 5 µm) with a mobile phase consisting of acetonitrile and a 10 mM sodium perchlorate buffer (38 : 62, v/v) at a flow rate of 1.0 mL·min-1 and UV detection at 220 nm. The selectivity, method linearity, accuracy, and precision were examined as part of the method validation. The described method shows excellent linearity over a range of 30 to 70 µg·mL-1 for all compounds with correlation coefficients higher than 0.995. The standard deviations of the intraday and interday precision were between 0.75 and 1.94%. The validated method was successfully applied to perform routine analysis of these compounds in different pharmaceutical products such as syrups and tablets. In the presence of some preservatives, it was found that there were no peaks at the related peak locations.

Inward Glucose Transfer Accounts for Insulin-Dependent Increase in Brain Glucose Metabolism Associated with Diet-Induced Obesity.

OBJECTIVE: There is a general agreement that there are changes in brain metabolism in insulin-resistant individuals during conditions of hyperinsulinemia. However, the impact on obesity is unclear, and the metabolic constants underlying these modifications are unknown. The aim of this study was to evaluate these changes in a large animal model of diet-induced obesity. METHODS: Twenty adult miniature pigs were fed with either an obesogenic diet or a regular diet for 5 months. At that time, fat deposition was evaluated using computed tomography scanning, and 18 fluorodeoxyglucose positron emission tomography images were acquired dynamically both in the fasted state and during a euglycemic-hyperinsulinemic clamp. Glucose uptake rates and pixel-wise modeled brain volumes were calculated together with brain connectivity. RESULTS: Whole-body insulin sensitivity was reduced by more than 50% in the obesity group. During insulin stimulation, whole-brain insulin-induced increased glucose uptake was unaltered in lean animals but increased markedly in the animals with obesity. The increased glucose uptake reflected an increase in the inward transfer without changes in phosphorylation or outward brain transport. Connectivity was increased in the animals with obesity CONCLUSIONS: Diet-induced obesity is associated with an increase in insulin-stimulated brain glucose uptake as a consequence of a larger inward transfer. These changes occurred together with an increased connectivity in reference to regions associated with memory recollection.

Development of an extraction method for anabolic androgenic steroids in dietary supplements and analysis by gas chromatography-mass spectrometry: Application for doping-control.

Several studies have highlighted that nutritional supplements may contain undeclared anabolic steroids that are banned by the International Olympic Committee/World Anti-Doping Agency. Any kind of abuse with these drugs is extremely dangerous because of their side effects. Thus, the control of food additives in order to protect the best consumer health and to limit fraudulent practices in the field of sports is essential. This paper describes a simple and effective qualitative gas chromatography-mass spectrometry (GC-MS) method to detect anabolic androgenic steroids (AAS): androsterone, nandrolene, dehydroepiandrosterone, 5ɑ-androstane-3ß, 17ß-diol, dihydrotestosterone, testosterone, methenolone acetate, methandienone, boldenone and fluoxymesterone, in food supplements. Methyltestosterone was used as internal standard. Target compounds were extracted with a mixture of N-pentane and di-ethylether (7.5:2.5, v/v). A good extraction recovery was obtained by our method for all the AAS (R > 88%). Crude extract was derivatized with N-methyl-N-trimethylsilyl-trifluoracetamide. Separation was performed on a GC connected to quadrupole MS detector using a 5% phenylmethylsiloxane fused silica capillary column (30 m × 0.25 mm i.d.; film thickness, 0.25 µm). Helium was used as carrier gas with a flow rate of 0.3 µl min-1 (measured at 6.1 psi 190 °C). The MS was operated in electron ionization mode (70 eV) and in selected ion monitoring (SIM). The mass spectra of the standard compounds were acquired in full SCAN mode (50-700 m/z) by infusion of a reference solution at 50 µg/ml. Three higher diagnostic ions were monitored for each compound of interest. All AAS get separated with good peak shapes and resolution factor. The total analysis time by our optimised method was only 20 min. The developed method was validated according to Laboratories International Standard regulations for specificity, precision in both liquid and solid matrixes, and memory effect. The Tolerance Interval was judged true. The limit of detection was about 10 ng/g for solid samples and 10 ng/ml for liquid samples. The developed method was then applied to the research of steroids in nine Tunisian commercially dietary supplements using for each compound of interest SIM mode for screening then SCAN mode for confirmation. One of the monitoring samples was positive to methandienone not declared on the label. Our analytical method can be beneficial for AAS screening in dietary supplements.

The allosteric citalopram binding site differentially interferes with neuronal firing rate and SERT trafficking in serotonergic neurons.

Citalopram is a clinically applied selective serotonin re-uptake inhibitor for antidepressant pharmacotherapy. It consists of two enantiomers, S-citalopram (escitalopram) and R-citalopram, of which escitalopram exerts the antidepressant therapeutic effect and has been shown to be one of the most efficient antidepressants, while R-citalopram antagonizes escitalopram via an unknown molecular mechanism that may depend on binding to a low-affinity allosteric binding site of the serotonin transporter. However, the precise mechanism of antidepressant regulation of the serotonin transporter by citalopram enantiomers still remains elusive. Here we investigate escitalopram׳s acute effect on (1) serotonergic neuronal firing in transgenic mice that express the human serotonin transporter without and with a mutation that disables the allosteric binding site, and (2) regulation of the serotonin transporter׳s cell surface localization in stem cell-derived serotonergic neurons. Our results demonstrate that escitalopram inhibited neuronal firing less potently in the mouse line featuring a mutation that abolishes the function of the allosteric binding site and induced serotonin transporter internalization independently of the allosteric binding site mechanism. Furthermore, citalopram enantiomers dose-dependently induced serotonin transporter internalization. In conclusion, this study provides new insight into antidepressant effects exerted by citalopram enantiomers in presence and absence of a functional allosteric binding site.

Citrulline: from metabolism to therapeutic use.

Citrulline possesses a highly specific metabolism that bypasses splanchnic extraction because it is not used by the intestine or taken up by the liver. The administration of citrulline may be used to deliver available nitrogen for protein homeostasis in peripheral tissues and as an arginine precursor synthesized de novo in the kidneys and endothelial and immune cells. Fresh research has shown that citrulline is efficiently transported across the intestinal luminal membrane by a set of transporters belonging to the B°,⁺, L, and b°,⁺ systems. Several pharmacokinetic studies have confirmed that citrulline is efficiently absorbed when administered orally. Oral citrulline could be used to deliver arginine to the systemic circulation or as a protein anabolic agent in specific clinical situations, because recent data have suggested that citrulline, although not a component of proteins, stimulates protein synthesis in skeletal muscle through the mammalian target of rapamycin signaling pathway. Hence, citrulline could play a pivotal role in maintaining protein homeostasis and is a promising pharmaconutrient in nutritional support strategies for malnourished patients, especially in aging and sarcopenia.

Mechanisms and kinetics of citrulline uptake in a model of human intestinal epithelial cells.

BACKGROUND & AIMS: Citrulline is a major precursor of arginine by de novo synthesis in the kidneys. Oral citrulline supplementation may be beneficial in some clinical conditions. However, citrulline bioavailability depends on its intestinal absorption. Since the mechanism of citrulline transport across the intestine has not been established yet, this study was designed to characterize L-[(14)C]-citrulline uptake by Caco-2 cells. METHODS: Caco-2 cells were cultured in a bicameral insert system. Inhibition studies were conducted in the presence of neutral, cationic, acidic and non-metabolized amino acids. We performed control inhibition studies for arginine uptake. RESULTS: Citrulline uptake was pH-independent whereas the uptake rate was reduced in the absence of Na(+). Kinetic analysis indicated the involvement of Na(+)-dependent and Na(+)-independent saturable transport components. For competition studies, both the transport components were markedly inhibited by large, small neutral and cationic amino acids. It was also noticed that specific inhibitor of system lBCH inhibited uptake. The inhibition profile of arginine transport was different from that of citrulline transport as arginine uptake was insensitive to BCH. CONCLUSIONS: These characteristics suggest that system B(0,+) might be responsible for the Na(+)-dependent uptake of citrulline, whereas Na(+)-independent uptake may include systems L and b(0,+). Our results show that systems involved in citrulline transport are partly different from those involved in arginine transport.