Study of quercetin-loaded liposomes as potential drug carriers: in vitro evaluation of human complement activation

Liposomes have been employed as potential drug carriers. However, after their in vivo administration, they can be destabilized by proteins of complement system, contributing to the clearance of vesicles from blood circulation. Antioxidant flavonoids such as quercetin have been reported to be beneficial to human health, but their low water solubility and bioavailability limit their enteric administration. Therefore, the development of appropriate flavonoid-carriers could be of great importance to drug therapy. The aim of the present study was to evaluate the activation of human complement system proteins by liposomes composed of soya phosphatidylcholine (SPC) and cholesterol (CHOL) or cholesteryl ethyl ether (CHOL-OET) loaded with quercetin or not. The consumption of complement, via classical (CP) and alternative (AP) pathways, by different vesicles was evaluated using a hemolytic assay and quantitative determination of iC3b and natural antibodies deposited on empty liposomal surfaces by ELISA. The main results showed that empty liposomes composed of large amounts of CHOL consumed more complement components than the others for both CP and AP. Furthermore, replacement of CHOL with CHOL-OET reduced complement consumption via both CP and AP. Incorporation of quercetin did not change CP and AP consumption. Deposition of iC3b, IgG and IgM in vesicles composed of SPC: CHOL-OET at a molar ratio of 1.5:1 was lower compared to the others. Taken together, these observations suggest that liposomes composed of SPC: CHOL-OET at a molar ratio of 1.5:1 are the most appropriate among the vesicles studied herein to be used as a drug carrier system in further investigations.

Evaluation of the in vitro Activity of Dermaseptin 01, a Cationic Antimicrobial Peptide, against Schistosoma mansoni

Schistosomiasis is a neglected tropical disease that remains a considerable public health problem worldwide. Since the mainstay of schistosomiasis control is chemotherapy with a single drug, praziquantel, drug resistance is a concern. Here, we examined the in vitro effects of dermaseptin 01 (DS 01), an antimicrobial peptide found in the skin secretion of frogs of the genus Phyllomedusa, on Schistosoma mansoni adult worms. DS 01 at a concentration of 100 mg/ml reduced the worm motor activity and caused the death of all worms within 48 h in RPMI 1640 medium. At the highest sublethal concentration of antimicrobial peptide (75 mg/ml), a 100% reduction in egg output of paired female worms was observed. Additionally, DS 01 induced morphological alterations on the tegument of S. mansoni, and a quantitative analysis carried out by confocal microscopy revealed extensive destruction of the tubercles in a dose-dependent manner over the concentration range of 50-200 mu g/ml. It was the first time that an anthelmintic activity towards schistosomes has been reported for a dermaseptin.

Development of albendazole sulfoxide-loaded Eudragit microparticles: A potential strategy to improve the drug bioavailability

Albendazole sulfoxide (ABZSO), a broad spectrum anthelmintic drug extensively used in veterinary medicine, exhibits a low and erratic bioavailability due to its poor solubility in biological fluids. The aims of this study were the development, physicochemical characterization, and in vitro release profile evaluation of ABZSO-loaded Eudragit RS PO (R) microparticles (MPs) in order to improve the rate of dissolution and the dissolved percentage of the drug in pH 7.4. MPs were successfully obtained by the emulsification/solvent evaporation method, achieving entrapment efficiency and process yield of about 60% and mean size of 254 nm. The in vitro release profile study showed that dissolution of ABZSO followed a pseudo-second order kinetics and MPs were able to increase significantly (p < 0.05) the rate of dissolution of ABZSO compared to the micronized and non-micronized free drug, what could lead to an improvement in bioavailability and, consequently, in the antiparasitic activity. (C) 2011 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Interchangeability among therapeutic equivalents of lamotrigine: evaluation of quality of life

Epilepsy is the most common serious neurological disorder worldwide. Approximately 70% of patients with epilepsy have their seizures controlled by clinical and pharmacological treatment. This research evaluated the possible influence of interchangeability among therapeutic equivalents of LTG on the clinical condition and quality of life of refractory epileptic patients. The study was divided into three periods of 42 days, and an equivalent therapeutic LTG randomly dispensed for each period (two similars - formulations A and B, and the reference product - formulation C). The mean dose of LTG was 5.5 mg/kg/day. The presence of side effects tends to have a greater deleterious effect on quality of life of refractory epileptics compared to variations in number of seizures or changes in plasma concentrations. The results showed that independently of the drug prescribed, interchangeability among therapeutic equivalents can negatively impact epilepsy control.

Schistosomicidal evaluation of flavonoids from two species of Styrax against Schistosoma mansoni adult worms

Context: Schistosomiasis is a major health problem worldwide. Thus, the search for new schistosomicidal agents from natural sources can provide prototypes for drug discovery. Objective: The present study investigated the chemical composition of the EtOAc fractions of Styrax pohlii Pohl (Styracaceae) (EF-SP) aerial parts and S. camporum A. DC. leaves (EF-SC), as well as schistosomicidal activities against Schistosoma mansoni adult worms, which have not yet been studied. Materials and methods: The crude ethanol extracts of S. camporum leaves and S. pohlii aerial parts (EE-SC and EE-SP) were partitioned with n-hexane, EtOAc, and n-BuOH. The EtOAc fractions were purified by preparative HPLC. The crude extracts, EtOAc fractions and pure compounds were tested against S. mansoni adult worms in vitro. Results: The purification procedure resulted in the isolation of kaempferol-3-O-(2 '',4 ''-di-O-(E)-p-coumaroyl)-beta-D-glucopyranoside (1), kaempferol-3-O-(2 '',6 ''-di-O-(E)-p-coumaroyl)-beta-D-glucopyranoside (2), quercetin (3), and kaempferol (4). The bioassay results indicated that EE-SC, EF-SC, EF-SP, and compounds 2 and 4 are able to separate coupled S. mansoni adult worms. Additionally, EE-SC, EF-SP, and compound 4 killed the adult schistosomes in vitro at 100 mu g/mL and 100 mu M. Discussion and conclusion: This is the first time that the presence of compounds 1-2 in S. pohlii and 3-4 in S. camporum has been reported. Additionally, biological results indicated that S. pohlii and S. camporum have great potential as a source of active compounds.

On the search for potential anti-Trypanosoma cruzi drugs: Synthesis and biological evaluation of 2-hydroxy-3-methylamino and 1,2,3-triazolic naphthoquinoidal compounds obtained by click chemistry reactions

Five 2-hydroxy-3-substituted-aminomethyl naphthoquinones, nine 1,2,3-triazolic para-naphthoquinones, five nor-beta-lapachone-based 1,2,3-triazoles, and several other naphthoquinonoid compounds were synthesized and evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease, continuing our screening program for new trypanocidal compounds. Among all the substances, 16-18, 23, 25-29 and 30-33 were herein described for the first time and fifteen substances were identified as more potent than the standard drug benznidazole, with IC50/24 h values in the range of 10.9-101.5 mu M. Compounds 14 and 19 with Selectivity Index of 18.9 and 6.1 are important structures for further studies. (C) 2012 Elsevier Masson SAS. All rights reserved.

The Future REvascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease (FREEDOM) trial: Clinical and angiographic profile at study entry

Background The optimal revascularization strategy for diabetic patients with multivessel coronary artery disease (MVD) remains uncertain for lack of an adequately powered, randomized trial. The FREEDOM trial was designed to compare contemporary coronary artery bypass grafting (CABG) to percutaneous coronary intervention (PCI) with drug-eluting stents in diabetic patients with MVD against a background of optimal medical therapy. Methods A total of 1,900 diabetic participants with MVD were randomized to PCI or CABG worldwide from April 2005 to March 2010. FREEDOM is a superiority trial with a mean follow-up of 4.37 years (minimum 2 years) and 80% power to detect a 27.0% relative reduction. We present the baseline characteristics of patients screened and randomized, and provide a comparison with other MVD trials involving diabetic patients. Results The randomized cohort was 63.1 +/- 9.1 years old and 29% female, with a median diabetes duration of 10.2 +/- 8.9 years. Most (83%) had 3-vessel disease and on average took 5.5 +/- 1.7 vascular medications, with 32% on insulin therapy. Nearly all had hypertension and/or dyslipidemia, and 26% had a prior myocardial infarction. Mean hemoglobin A1c was 7.8 +/- 1.7 mg/dL, 29% had low-density lipoprotein <70 mg/dL, and mean systolic blood pressure was 134 +/- 20 mm Hg. The mean SYNTAX score was 26.2 with a symmetric distribution. FREEDOM trial participants have baseline characteristics similar to those of contemporary multivessel and diabetes trial cohorts. Conclusions The FREEDOM trial has successfully recruited a high-risk diabetic MVD cohort. Follow-up efforts include aggressive monitoring to optimize background risk factor control. FREEDOM will contribute significantly to the PCI versus CABG debate in diabetic patients with MVD. (Am Heart J 2012;164:591-9.)

US Food and Drug Administration approval of generic versions of complex biologics: implications for the practicing physician using low molecular weight heparins

Low-molecular-weight heparins (LMWHs) have shown equivalent or superior efficacy and safety to unfractionated heparin as antithrombotic therapy for patients with acute coronary syndromes. Each approved LMWH is a pleotropic biological agent with a unique chemical, biochemical, biophysical and biological profile and displays different pharmacodynamic and pharmacokinetic profiles. As a result, LMWHs are neither equipotent in preclinical assays nor equivalent in terms of their clinical efficacy and safety. Previously, the US Food and Drug Administration (FDA) cautioned against using various LMWHs interchangeably, however recently, the FDA approved generic versions of LMWH that have not been tested in large clinical trials. This paper highlights the bio-chemical and pharmacological differences between the LMWH preparations that may result in different clinical outcomes, and also reviews the implications and challenges physicians face when generic versions of the original/innovator agents are approved for clinical use.

In vivo evaluation of a metronidazole-containing gel for the adjuvant treatment of chronic periodontitis: preliminary results

The present study developed an experimental metronidazole-based gel and evaluated its efficacy for the adjuvant treatment of chronic periodontitis. Sixteen patients were randomly allocated into two groups of eight subjects according to the following proposed treatments: (1) scaling and root planing (active control) or (2) scaling and root planing and direct periodontal intrapocket application of 15% metronidazole-based gel in two sites (a parts per thousand yen5 mm in depth) (experimental group). Potential changes in the subgingival microbiota were assessed using a DNA Checkerboard method at three proposed times: baseline and following 7 or 30 days of drug administration. High-performance liquid chromatography (HPLC) monitored metronidazole concentrations in the crevicular fluid during treatment. The metronidazole experimental group presented lower bacterial counts than the control group at the three evaluated times (p < 0.01 for baseline, p < 0.001 for 7 or 30 days) when the target species were analyzed as a pool of bacteria. Samples revealed significantly lower counts 7 days after drug administration compared with baseline or after 30 days (p < 0.05). HPLC analysis detected gel 1 h after application. The metronidazole-based gel significantly decreased the total bacterial count at the three evaluated times. Periodontopathogenic species were not different after gel administration.

DETERMINATION OF DICLOFENAC SODIUM IN RABBIT PLASMA BY HPLC/UV: EVALUATION AND CHARACTERIZATION OF ITS CRYSTALLINE FORMS, ANHYDROUS AND HYDRATE, ON THE ANTIPYRETIC EFFECT

Diclofenac sodium (DS) is a non-steroidal anti-inflammatory drug that is widely prescribed for the treatment of rheumatoid arthritis and post-surgery analgesia. The active pharmaceutical ingredient is the anhydrous form; however, it can also exist in hydrate form. In this context, knowing the properties of the solid state is important and relevant in the pharmaceutical area because they have a significant impact on the solubility, bioavailability, and chemical stability of the drugs. In the present study, data from XRPD, FTIR spectroscopy, and thermal analysis were used for the identification and characterization of DS forms (anhydrous and hydrate). An HPLC method was optimized to evaluate the plasma concentration of DS in rabbits. The optimized method exhibited good linearity over the range 0.1-60 mu g/mL with correlation coefficients of >0.9991. The mean recovery was 100%. Precision and accuracy were determined within acceptable limits. Finally, to compare the pharmacological properties of anhydrous and hydrate DS forms, we investigated their effects in the febrile response induced by lipopolysaccharide from E. coli in rabbits. The results show that the antipyretic effect of anhydrous and hydrate DS forms are similar.

Evaluation of Adrenal Reserve in Children with Acute Lymphocytic Leukemia Treated with Prednisone or Dexamethasone

Background/Aims: The purpose of this study was to compare adrenal gland reserve in acute lymphocytic leukemia (ALL) patients 8 weeks after treatment with either prednisone (PRED) or dexamethasone (DEX) during the induction phase of therapy. Methods: A double-blind comparative study of patients treated with PRED and DEX was performed. Sixteen patients received PRED (40 mg/m(2)/day) and 13 patients received DEX (6 mg/m(2)/day), both for 28 days. A low-dose adrenocorticotropic hormone test (1.0 mu g/m(2), IV) was performed before and weekly for 8 weeks after abrupt cessation of glucocorticoid therapy. Sixteen children without ALL were used as controls to determine the cutoff peak cortisol level (14.2 mu g/dl). Results: Both groups (PRED and DEX) displayed similar mean peak cortisol levels before treatment and during the 8 weeks of evaluation (p = 0.652). No relationship was observed between the incidence of infection/stress and peak cortisol level within each group, nor was there a difference in the frequency of infection/stress between groups (p = 0.359). Although the patients presented variations in peak cortisol during the study period, no signs or symptoms of adrenal insufficiency were observed. Conclusion: Patients who received PRED or DEX for 4 weeks showed similar adrenal reserves and infection rates for 8 weeks after abruptly stopping glucocorticoid therapy, suggesting that DEX, which is a better antileukemic drug than PRED, has similar adrenal suppression and recovery rates. Copyright (c) 2012 S. Karger AG, Basel

Audiometric evaluation of patients treated for pulmonary tuberculosis

Objective: To evaluate the hearing status of patients being treated for pulmonary tuberculosis at referral hospitals in Brazil. Methods: This was a descriptive study involving 97 male and female inpatients/outpatients between 18 and 60 years of age who were undergoing treatment for active pulmonary tuberculosis at one of two referral hospitals in the state of Rio de Janeiro. After being interviewed, all of the patients underwent pure tone audiometry. Results: OF the 97 patients studied, 65 (67%) were male, 52 (54%) were receiving first-line treatment, and 45 (46%) were receiving second-line treatment, which included aminoglycosides. Smoking, alcohol consumption, exposure to noise, and ototoxic medication use were identified in 65 (67%), 51 (53%), 53 (55%), and 45 (46.4%) of the patients, respectively. The most common auditory and vestibular complaints were dizziness, in 28 patients (28.8%); tinnitus, in 27 (27.8%); and hypoacusis, in 23 (23.7%). Conclusions: Due to the great number of patients with hearing loss in the present study, we recommend that all patients under tuberculosis treatment be submitted to auditory monitoring.

Evaluation of HIV-1 resistance to antiretroviral drugs among 150 patients after six months of therapeutic interruption

Most of the antiretroviral (ARV) studies in Brazil have been reported in treatment-experienced and naive patients rather than in the setting of treatment interruption (TI). In this study, we analysed reasons given for TI and resistance mutations occurring in 150 HIV-1-infected patients who underwent TI. Of the patients analysed, 110 (73.3%) experienced TI following medical advice, while the remaining patients stopped antiretroviral therapy (ART) of their own accord. The main justifications for TI were: ARV-related toxicities (38.7%), good laboratory parameters (30%) and poor adherence (20%). DNA sequencing of the partial pol gene was successful in 137 (91.3%) patients, of whom 38 (27.7%) presented mutations conferring ARV resistance. A higher viral load prior to TI correlated with drug resistance (P < 0.05). Our results demonstrate that there are diverse rationales for TI and that detection of resistant strains during TI most likely indicates a fitter virus than the wild type. High viral loads coupled with unprotected sex in this group could increase the likelihood of transmission of drug-resistant virus. Thus, treating physicians should be alerted to this problem when the use of ARVs is interrupted.

Synthesis, Biological Evaluation, And Molecular Modeling of Chalcone Derivatives As Potent Inhibitors of Mycobacterium tuberculosis Protein Tyrosine Phosphatases (PtpA and PtpB)

Tuberculosis (TB) is a major infectious disease caused by Mycobacterium tuberculosis (Mtb). According to the World Health Organization (WHO), about 1.8 million people die from TB and 10 million new cases are recorded each year. Recently, a new series of naphthylchalcones has been identified as inhibitors of Mtb protein tyrosine phosphatases (PTPs). In this work, 100 chalcones were designed, synthesized, and investigated for their inhibitory properties against MtbPtps. Structure-activity relationships (SAR) were developed, leading to the discovery of new potent inhibitors with IC50 values in the low-micromolar range. Kinetic studies revealed competitive inhibition and high selectivity toward the Mtb enzymes. Molecular modeling investigations were carried out with the aim of revealing the most relevant structural requirements underlying the binding affinity and selectivity of this series of inhibitors as potential anti-TB drugs.

Solid Dispersion of Ursolic Acid in Gelucire 50/13: a Strategy to Enhance Drug Release and Trypanocidal Activity

Solid dispersions (SDs) are an approach to increasing the water solubility and bioavailability of lipophilic drugs such as ursolic acid (UA), a triterpenoid with trypanocidal activity. In this work, Gelucire 50/13, a surfactant compound with permeability-enhancing properties, and silicon dioxide, a drying adjuvant, were employed to produce SDs with UA. SDs and physical mixtures (PMs) in different drug/carrier ratios were characterized and compared using differential scanning calorimetry, hot stage microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size, water solubility values, and dissolution profiles. Moreover, LLC-MK2 fibroblast cytotoxicity and trypanocidal activity evaluation were performed to determine the potential of SD as a strategy to improve UA efficacy against Chagas disease. The results demonstrated the conversion of UA from the crystalline to the amorphous state through XRD. FTIR experiments provided evidence of intermolecular interactions among the drug and carriers through carbonyl peak broadening in the SDs. These findings helped explain the enhancement of water solubility from 75.98 mu g/mL in PMs to 293.43 mu g/mL in SDs and the faster drug release into aqueous media compared with pure UA or PMs, which was maintained after 6 months at room temperature. Importantly, improved SD dissolution was accompanied by higher UA activity against trypomastigote forms of Trypanosoma cruzi, but not against mammalian fibroblasts, enhancing the potential of UA for Chagas disease treatment.