Synergistic interaction between trazodone and gabapentin in rodent models of neuropathic pain.

Neuropathic pain is a chronic debilitating condition caused by injury or disease of the nerves of the somatosensory system. Although several therapeutic approaches are recommended, none has emerged as an optimal treatment leaving a need for developing more effective therapies. Given the small number of approved drugs and their limited clinical efficacy, combining drugs with different mechanisms of action is frequently used to yield greater efficacy. We demonstrate that the combination of trazodone, a multifunctional drug for the treatment of major depressive disorders, and gabapentin, a GABA analogue approved for neuropathic pain relief, results in a synergistic antinociceptive effect in the mice writhing test. To explore the potential relevance of this finding in chronic neuropathic pain, pharmacodynamic interactions between low doses of trazodone (0.3 mg/kg) and gabapentin (3 mg/kg) were evaluated in the chronic constriction injury (CCI) rat model, measuring the effects of the two drugs both on evoked and spontaneous nociception and on general well being components. Two innate behaviors, burrowing and nest building, were used to assess these aspects. Besides exerting a significant antinociceptive effect on hyperalgesia and on spontaneous pain, combined inactive doses of trazodone and gabapentin restored in CCI rats innate behaviors that are strongly reduced or even abolished during persistent nociception, suggesting that the combination may have an impact also on pain components different from somatosensory perception. Our results support the development of a trazodone and gabapentin low doses combination product for optimal multimodal analgesia treatment.

Management and Treatment of Patients With Major Depressive Disorder and Chronic Diseases: A Multidisciplinary Approach.

In patients with physical chronic diseases, the prevalence of major depressive disorder (MDD) is approximately 2- to 3-fold higher than in the general population, and it can reach up to 20-40%. The comorbidity of MDD with chronic medical diseases is associated with poorer quality of life, increased medical symptom burden, poor adherence to self-care regimens, increased risk of functional impairment, morbidity, and mortality, and also higher medical costs. Despite this evidence, in routine practice, psychological issues and concerns are frequently inadequately managed. This consensus document proposes that a proper diagnosis, a multidisciplinary approach, and a personalized treatment plan would allow patients with MDD and chronic comorbidities to be more compliant, to improve the outcomes, to reduce possible relapses in the long term, and to prevent or better manage complications and adverse events. This proposal might be useful for any health professionals who deal with patients with chronic diseases, as it can help to pay more attention to the emotional impact of these conditions, in particular in terms of depressive symptoms.

Acute Low Dose of Trazodone Recovers Glutamate Release Efficiency and mGlu2/3 Autoreceptor Impairments in the Spinal Cord of Rats Suffering From Chronic Sciatic Ligation.

We investigated whether chronic sciatic ligation modifies the glutamate release in spinal cord nerve endings (synaptosomes) as well as the expression and the function of presynaptic release-regulating mGlu2/3 autoreceptors and 5-HT2A heteroreceptors in these particles. Synaptosomes were from the spinal cord of animals suffering from the sciatic ligation that developed on day 6 post-surgery a significant decrease of the force inducing paw-withdrawal in the lesioned paw. The exocytosis of glutamate (quantified as release of preloaded [3H]D-aspartate, [3H]D-Asp) elicited by a mild depolarizing stimulus (15 mM KCl) was significantly increased in synaptosomes from injured rats when compared to controls (uninjured rats). The mGlu2/3 agonist LY379268 (1000 pM) significantly inhibited the 15 mM KCl-evoked [3H]D-Asp overflow from control synaptosomes, but not in terminals isolated from injured animals. Differently, a low concentration (10 nM) of (±) DOI, unable to modify the 15 mM KCl-evoked [3H]D-Asp overflow in control spinal cord synaptosomes, significantly reduced the glutamate exocytosis in nerve endings isolated from the injured rats. Acute oral trazodone (TZD, 0.3 mg/kg on day 7 post-surgery) efficiently recovered glutamate exocytosis as well as the efficiency of LY379268 in inhibiting this event in spinal cord synaptosomes from injured animals. The sciatic ligation significantly reduced the expression of mGlu2/3, but not of 5-HT2A, receptor proteins in spinal cord synaptosomal lysates. Acute TZD recovered this parameter. Our results support the use of 5-HT2A antagonists for restoring altered spinal cord glutamate plasticity in rats suffering from sciatic ligation.

The mood stabilizing properties of AF3581, a novel potent GSK-3ß inhibitor.

Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzymeand highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients.

Antibacterial activity of novel dual bacterial DNA type II topoisomerase inhibitors.

In this study, a drug discovery programme that sought to identify novel dual bacterial topoisomerase II inhibitors (NBTIs) led to the selection of six optimized compounds. In enzymatic assays, the molecules showed equivalent dual-targeting activity against the DNA gyrase and topoisomerase IV enzymes of Staphylococcus aureus and Escherichia coli. Consistently, the compounds demonstrated potent activity in susceptibility tests against various Gram-positive and Gram-negative reference species, including ciprofloxacin-resistant strains. The activity of the compounds against clinical multidrug-resistant isolates of S. aureus, Clostridium difficile, Acinetobacter baumannii, Neisseria gonorrhoeae, E. coli and vancomycin-resistant Enterococcus spp. was also confirmed. Two compounds (1 and 2) were tested in time-kill and post-antibiotic effect (PAE) assays. Compound 1 was bactericidal against all tested reference strains and showed higher activity than ciprofloxacin, and compound 2 showed a prolonged PAE, even against the ciprofloxacin-resistant S. aureus BAA-1720 strain. Spontaneous development of resistance to both compounds was selected for in S. aureus at frequencies comparable to those obtained for quinolones and other NBTIs. S. aureus BAA-1720 mutants resistant to compounds 1 and 2 had single point mutations in gyrA or gyrB outside of the quinolone resistance-determining region (QRDR), confirming the distinct site of action of these NBTIs compared to that of quinolones. Overall, the very good antibacterial activity of the compounds and their optimizable in vitro safety and physicochemical profile may have relevant implications for the development of new broad-spectrum antibiotics.

A randomized, double-blind study comparing the efficacy and safety of trazodone once-a-day and venlafaxine extended-release for the treatment of patients with major depressive disorder.

This double-blind, randomized study evaluated the efficacy and safety of trazodone OAD (once-a-day) in comparison with venlafaxine XR (extended-release) in 324 patients (166 trazodone and 158 venlafaxine) with major depressive disorder (MDD). The primary efficacy endpoint was the mean change from baseline in the 17-item Hamilton Depression Rating Scale (HAM-D) at week 8. Both treatments were effective in reducing the HAM-D-17 total score at week 8 vs. baseline (intent-to-treat: trazodone -12.9, venlafaxine -14.7; per protocol: trazodone -15.4, venlafaxine -16.4). Patients in the venlafaxine group achieved better results after 8 weeks, whereas the trazodone group achieved a statistically significant reduction in HAM-D-17 following only 7 days of treatment. The most frequent adverse events (AEs) were dizziness and somnolence in the trazodone group, and nausea and headache in the venlafaxine group. Most AEs were mild-to-moderate in severity. This study confirmed that both venlafaxine XR and trazodone OAD may represent a valid treatment option for patients with MDD.

Estimation of an Appropriate Dose of Trazodone for Pediatric Insomnia and the Potential for a Trazodone-Atomoxetine Interaction.

There is a paucity of clinical trials for the treatment of pediatric insomnia. This study was designed to predict the doses of trazodone to guide dosing in a clinical trial for pediatric insomnia using physiologically-based pharmacokinetic (PBPK) modeling. Data on the pharmacokinetics of trazodone in children are currently lacking. The interaction potential between trazodone and atomoxetine was also predicted. Doses predicted in the following age groups, with exposures corresponding to adult dosages of 30, 75, and 150 mg once a day (q.d.), respectively, were: (i) 2- to 6-year-old group, doses of 0.35, 0.8, and 1.6 mg/kg q.d.; (ii) >6- to 12-year-old group, doses of 0.4, 1.0, and 1.9 mg/kg q.d.; (iii) >12- to 17-year-old group, doses of 0.4, 1.1, and 2.1 mg/kg q.d. An interaction between trazodone and atomoxetine was predicted to be unlikely. Clinical trials based on the aforementioned predicted dosing are currently in progress, and pharmacokinetic data obtained will enable further refinement of the PBPK models.

In vitro time-kill kinetics of dalbavancin against Staphylococcus spp. biofilms over prolonged exposure times.

Staphylococcus aureus and Staphylococcus epidermidis are leading pathogens of biofilm-related infections and represent the most common cause of osteomyelitis and biomedical implants infections. Biofilm-related infections usually require long-term antibiotic treatment, often associated to surgical interventions. Dalbavancin is a newer lipoglycopeptide approved for the treatment of acute skin and skin-structure infections caused by Gram-positive pathogens. In addition, dalbavancin has recently been considered as a potential option for the treatment of staphylococcal osteomyelitis and orthopedic implant infections. In this study, time-kill kinetics of dalbavancin against S. aureus and S. epidermidis biofilms were determined over prolonged exposure times (up to 7 days), using both a standardized biofilm susceptibility model and biofilms grown onto relevant orthopedic biomaterials (i.e. titanium and cobalt-chrome disks). Dalbavancin (at concentrations achievable in bone and articular tissue) showed a potent activity against established staphylococcal biofilms in both tested models, and was overall superior to the comparator vancomycin.

Juvenile rat and pediatric trazodone studies: how to gain extra sensitivity to overcome bioanalytical challenges.

AIM: Trazodone (TZD) is used for the treatment of depression in adults and, off-label, as a sleep medication in adult and pediatric populations. The off-label use is well documented, however further clinical studies are needed to confirm its efficacy and safety for the treatment of sleep disorders. In this scenario, we developed a bioanalytical method to quantify low TZD concentrations in samples collected by capillary microsampling (CMS) to support dose finding, Good Laboratory Practice juvenile rat toxicokinetic and upcoming pediatric studies. METHODOLOGY: A method using only 8 µl of plasma was developed and successfully used for analyzing CMS samples from juvenile rats throughout toxicokinetic study. CONCLUSION: By harmoniously maximizing each analytical step, we achieved a sensitive method to quantify TZD in CMS samples.

New Insights on the Pharmacokinetics of Ulifloxacin After Administration of Prulifloxacin in Patients with Mild, Moderate and Severe Renal Impairment.

BACKGROUND: The antibacterial agent prulifloxacin, a prodrug of ulifloxacin, is indicated in the treatment of acute lower urinary tract infections, acute exacerbation of chronic bronchitis and acute bacterial rhinosinusitis. OBJECTIVE: We aimed to provide new insights on the pharmacokinetics (PK) of ulifloxacin in patients with different degrees of renal impairment. METHODS: A two-site, international, open-label, parallel-group, single- and repeated-dose study was performed. The drug was administered as a single dose of 600 mg to subjects with normal renal function and patients with mild, moderate and severe renal impairment. Subsequently, the same dose was administered daily for 7 days to subjects with normal renal function and patients with mild and moderate renal impairment, while a dose of 300 mg was administered daily for 7 days to patients with severe renal impairment. Plasma and urine ulifloxacin levels were measured. Complete safety evaluation was performed. RESULTS: Exposure to ulifloxacin increased as renal function decreased due to a lower ulifloxacin clearance. Ulifloxacin PK were significantly changed only in patients with severe renal impairment. The amount of ulifloxacin excreted in urine over a 24-h dosing period was similar in subjects with normal renal function and patients with mild impaired renal function, but lower in those with moderate and severe renal impairment. CONCLUSION: Our data show that prulifloxacin is a safe quinolone and is well tolerated in both subjects with normal renal function and patients with impaired renal function, requiring a minimal dosage adjustment only in patients with severe renal impairment.

5-HT2A-mGlu2/3 receptor complex in rat spinal cord glutamatergic nerve endings: A 5-HT2A to mGlu2/3 signalling to amplify presynaptic mechanism of auto-control of glutamate exocytosis.

Presynaptic mGlu2/3 autoreceptors exist in rat spinal cord nerve terminals as suggested by the finding that LY379268 inhibited the 15 mM KCl-evoked release of [3H]D-aspartate ([3H]D-Asp) in a LY341495-sensitive manner. Spinal cord glutamatergic nerve terminals also possess presynaptic release-regulating 5-HT2A heteroreceptors. Actually, the 15 mM KCl-evoked [3H]D-Asp exocytosis from spinal cord synaptosomes was reduced by the 5-HT2A agonist (±)DOI, an effect reversed by the 5-HT2A antagonists MDL11,939, MDL100907, ketanserin and trazodone (TZD). We investigated whether mGlu2/3 and 5-HT2A receptors colocalize and cross-talk in these terminals and if 5-HT2A ligands modulate the mGlu2/3-mediated control of glutamate exocytosis. Western blot analysis and confocal microscopy highlighted the presence of mGlu2/3 and 5-HT2A receptor proteins in spinal cord VGLUT1 positive synaptosomes, where mGlu2/3 and 5-HT2A receptor immunoreactivities largely colocalize. Furthermore, mGlu2/3 immunoprecipitates from spinal cord synaptosomes were also 5-HT2A immunopositive. Interestingly, the 100 pM LY379268-induced reduction of the 15 mM KCl-evoked [3H]D-Asp overflow as well as its inhibition by 100 nM (±)DOI became undetectable when the two agonists were concomitantly added. Conversely, 5-HT2A antagonists (MDL11,939, MDL100907, ketanserin and TZD) reinforced the release-regulating activity of mGlu2/3 autoreceptors. Increased expression of mGlu2/3 receptor proteins in synaptosomal plasmamembranes paralleled the gain of function of the mGlu2/3 autoreceptors elicited by 5-HT2A antagonists. Based on these results, we propose that in spinal cord glutamatergic terminals i) mGlu2/3 and 5-HT2A receptors colocalize and interact one each other in an antagonist-like manner, ii) 5-HT2A antagonists are indirect positive allosteric modulator of mGlu2/3 autoreceptors controlling glutamate exocytosis.

Preactivated thiolated glycogen as mucoadhesive polymer for drug delivery.

The purpose of this study was to synthesize and characterize a novel thiolated glycogen, so-named S-preactivated thiolated glycogen, as a mucosal drug delivery systems and the assessment of its mucoadhesive properties. In this regard, glycogen-cysteine and glycogen-cysteine-2-mercaptonicotinic acid conjugates were synthesized. Glycogen was activated by an oxidative ring opening with sodium periodate resulting in reactive aldehyde groups to which cysteine was bound via reductive amination. The obtained thiolated polymer displayed 2203.09±200µmol thiol groups per gram polymer. In a second step, the thiol moieties of thiolated glycogen were protected by disulfide bond formation with the thiolated aromatic residue 2-mercaptonicotinic acid (2MNA). In vitro screening of mucoadhesive properties was performed on porcine intestinal mucosa using different methods. In particular, in terms of rheology investigations of mucus/polymer mixtures, the S-preactivated thiolated glycogen showed a 4.7-fold increase in dynamic viscosity over a time period of 5h, in comparison to mucus/Simulated Intestinal Fluid control. The S-preactivated polymer remained attached on freshly excised porcine mucosa for 45h. Analogous results were obtained with tensile studies demonstrating a 2.7-fold increase in maximum detachment force and 3.1- fold increase in total work of adhesion for the S-preactivated polymer compared to unmodified glycogen. Moreover, water-uptake studies showed an over 4h continuing weight gain for the S-preactivated polymer, whereas disintegration took place for the unmodified polymer within the first hour. Furthermore, even in the highest tested concentration of 2mg/ml the new conjugates did not show any cytotoxicity on Caco-2 cell monolayer using an MTT assay. According to these results, S-preactivated glycogen represents a promising type of mucoadhesive polymers useful for the development of various mucosal drug delivery systems.

Natural dendrimers: Synthesis and in vitro characterization of glycogen-cysteamine conjugates.

The aim of this study was to synthesize, characterize and evaluate the mucoadhesive properties of the first thiolated hyperbranched natural polysaccharide with biodegradability and biocompatibility features. In detail, glycogen-cysteamine conjugates were synthesized through a first step of oxidative ring opening applying increasing concentrations of sodium periodate, to obtain polymers with different degrees of oxidation, and a second step of reductive amination with a constant amount of cysteamine. The obtained glycogen-cysteamine conjugates were characterized regarding their content of free and total thiol groups by Ellman's assay, biocompatibility, swelling/erosion behavior, rheological synergism and mucoadhesive properties in comparison to the unmodified glycogen. The higher the concentration of periodate was, the higher was the content of total thiol groups being in the range of 255.7±12-1194.5±82µmol/g, biocompatibility remained unaffected by these structural changes. On the contrary, the mucoadhesive properties, evaluated by tensile, rheological synergism and rotating cylinder studies, appear to be influenced by the thiol groups concentration on the glycogen. In particular the glycogen-cysteamine conjugate exhibiting the highest degree of thiolation showed a 79-fold increase in viscosity over a time period of 8h, as well as, remained attached on freshly excised porcine mucosa 32-fold longer than the unmodified polymer. The higher was the amount of conjugated thiol groups, the higher was the water absorption capacity of glycogen-cysteamine tablets in Simulated Intestinal Fluid pH 6.8 (SIF). The introduction of thiol moieties on polymer changed the characteristics of the polysaccharide by improving mucoadhesion properties. Therefore, this work represents the first study describing thiolated natural dendrimers as potential platform useful to realize appropriate mucoadhesive nanocarrier systems suitable to prolong mucosal residence time.

A New Acid-oxidizing Solution: Assessment of Its Role on Methicillin-resistant Staphylococcus aureus (MRSA) Biofilm Morphological Changes.

OBJECTIVE: Biofilms represent a key challenge in the treatment of chronic wounds, as they are among the main reasons for delays in chronic wound healing. This in vitro study was aimed at evaluating the activity of a new acid-oxidizing solution (AOS) on biofilm formation. Acid-oxidizing solution contains free chlorine species with stabilized hypochlorous acid in high concentration (> 95%) and is characterized by acidic (pH less than 3) and super-oxidizing (Redox greater than 1000mV) features. MATERIALS AND METHODS: A 3-dimensional in vitro model of reconstructed human epidermis was used to compare the activity of AOS vs 2 reference products (RP) containing betaine and polyhexanide (RP1) and sodium hypochlorite and hypochlorous acid (RP2). Different approaches were used to assess the prevention and eradication of methicillin-resistant Staphyloccocus aureus biofilm by the study products. Xylitol and chlorhexidine were used as positive controls. The activity of the study products on the biofilm structure was evaluated analyzing the ultrastructural modification by scanning electron microscopy, while skin compatibility was assessed on noncolonized tissues measuring the metabolic activity of the cells. RESULTS: In all experiments, AOS showed to be active on the biofilm matrix, modifying its structure and allowing bacterial release from the matrix. In all experiments, no cytotoxicity was observed in the tissues treated with the product suggesting a good compatibility of AOS with skin tissues. Reference product 1 affected the biofilm, suggesting a disruption effect; RP2 was slightly less active than AOS in modifying the biofilm structure. CONCLUSION: Treatment with AOS affects biofilm by modifying its structure and therefore facilitating local bacteria accessibility to bactericidal agents, with consequent potential clinical benefits in the treatment of chronic wounds.

New ethanol and propylene glycol free gel formulations containing a minoxidil-methyl-ß-cyclodextrin complex as promising tools for alopecia treatment.

New topical totally aqueous formulations that improve the low water solubility of minoxidil and realize an adequate permeability of drug in the skin are proposed. These formulations are lacking in propylene glycol and alcohol that are the principal irritant ingredients present in minoxidil commercial solutions. In order to enhance poor water solubility of minoxidil randomly methyl-ß-cyclodextrin was used, and four hydrogels such as, calcium alginate, sodium alginate, carbopol 934 and hydroxyethylcellulose were utilized to ensure a prolonged time of contact with the scalp. The inclusion complex minoxidil/methyl-ß-cyclodextrin with a molar ratio 1:1 was obtained by freeze drying and evaluated by NMR, FT-IR and DSC analysis. An apparent stability constant of formed inclusion complex was calculated by phase solubility diagram and its value was 400 M(-1). The solid inclusion complex was used to prepare gel formulations with similar dose to minoxidil commercial solution. The gels were evaluated for various technological parameters including rheological behavior, in vitro drug release and ex vivo permeation through pig skin. The best performance was observed for the calcium alginate formulation.

Characterization and release studies of liposomal gels containing glutathione/cyclodextrins complexes potentially useful for cutaneous administration.

The aim of this work is to develop and characterize a formulation intended for the cutaneous administration of glutathione (γ-glutamylcysteinylglycine, GSH), potentially useful for cellular defense against UV-induced damage. For this purpose, liposomes containing GSH or GSH/cyclodextrins(CDs) inclusion complexes as well as liposomes dispersed within a hydrophilic gel, were evaluated. These formulations were designed in order to obtain a system combining the advantages of liposomes as vehicles for topical drug delivery with those of CDs as penetration enhancers. The studied CDs were the natural (ß-CD) and chemically modified (i.e., HP-ß-CD and CH3 -ß-CD) cyclodextrins. The prepared liposomes showed homogeneous size distribution, mean diameter in the range 622-1435 nm, small positive charge (+3.1 to +6.6 mV), and encapsulation efficiency of the peptide in the range 13.6%-23.7%. Release studies showed that the presence of the oligosaccharide may influence to some extent the amount of drug released, whereas stability studies clearly point out that the incorporation in a hydrophilic gel of 2-hydroxyethylcellulose insures a stable formulation maintaining unchanged the characteristics of liposomal vesicles.

Sulfobutyl ether-alkyl ether mixed cyclodextrin derivatives with enhanced inclusion ability.

The aim of this work was to study the complexation capability of new sulfobutyl ether-alkyl ether (SBE-AE-CD) mixed beta- and gamma-cyclodextrin derivatives with a series of structurally related steroids (6alpha-methylprednisolone, prednisolone, triamcinolone, D(-) norgestrel and hydrocortisone) and a number of dihydropyridine calcium channel blockers (nimodipine, nitrendipine, nifedipine) that traditionally interact poorly with other cyclodextrins (CDs). The effect of the total degree of substitution (TDS) and of the length of the alkyl side chain on binding capacity of these new modified CDs was evaluated as was their ability to induce red blood cell hemolysis. An attempt was made to correlate hemolysis to surface activity. Binding constants between the SBE-AE-CDs and selected molecules were determined by spectroscopic studies, and only in few cases by solubility studies. Hemolysis percentage was determined using citrated rabbit blood and citrated human blood with UV analysis. The surface activity was measured with a tensiometer. A significant improvement in the binding capacity between various substrates and the new SBE-AE-CDs was observed when compared to the SBE-CDs. The length of the alkyl chain and total degree of alkylation affected the binding with the relationship being complex. For most compounds, an intermediate degree of substitution appeared to be advantageous. The hemolysis studies showed that some of the derivatives may induce hemolysis and this correlated with higher surface activity for some but not all of the derivatives.

A study of free radical release from beta-cyclodextrin-anticancer pro-drugs adducts in water.

A novel approach in cancer chemotherapy concerns the attempt to employ radical affording substances (RAS) as pro-drugs able to produce irreversible damages on the tumor cell, so stimulating cellular apoptosis. However, radical species can react quickly towards the chemical environment into which they have been generated before reaching their proper sites of action, i.e. the tumor cells. We recently started a study aiming to accomplish new therapeutic systems for the transport of RAS in biological medium. In this paper we report the effect of stabilization produced by beta-cyclodextrin on carbon centered radicals afforded by some mercaptopyridine congeners which have already been shown to possess strong anticancer activity in vitro. EPR experiments carried out on aqueous solutions of N-acyloxy-pyridinethione analogues like 1 (R = adamantyl, cyclohexyl) in the presence of beta-cyclodextrin, demonstrated that photochemically produced alkyl radicals are involved in an adduct with beta-cyclodextrin which works as a cage preventing the interaction of such radicals with the medium. Furthermore, the presence of beta-cyclodextrin has been shown to delay the generation of radicals in water due to a possible interaction between the cyclodextrin cavity and the mercaptopyridine moiety of 1 which is the part of the molecule responsible for beginning the radical event.

Sulfoalkyl ether-alkyl ether cyclodextrin derivatives, their synthesis, NMR characterization, and binding of 6alpha-methylprednisolone.

The objective of this study is to see if random alkyl ethers of various sulfoalkyl ether cyclodextrins can be synthesized and characterized. The purpose of the alkylation was to test the hypothesis that an increase in the "height" of a cyclodextrins cavity would help in the binding/complexation of larger more structurally complex molecules. The synthesis of new cyclodextrin derivatives comprising a mixture of sulfoalkyl ether and alkyl ether substituents on the same cyclodextrin ring was performed in aqueous alkaline solutions using various sultones and alkylsulfates. The method presented provided an easy and efficient way to modify cyclodextrins avoiding the use of organic solvents and high quantities of alkylating agents and could be carried out in either a two step or "one pot" single step process. Purification was by neutralization followed by ultrafiltration. The derivatives were characterized by 1D, ((1)H and (13)C), and a 2D NMR technique (HMQC, Heteronuclear Multiple Quantum Coherence). The combination of these techniques allowed an analysis of the degree of substitution and the site of substitution on the cyclodextrin (CD) nucleus. For both beta- and gamma-CD, sulfoakylation was preferred on the 2 > 3 > 6 hydroxyls while alkylation was preferred 6 > 2 > 3. Due to the simultaneous presence of short alkyl ether chains and negatively charged sulfoalkyl ether chains, these mixed water-soluble cyclodextrin derivatives, especially those of gamma-cyclodextrin, should be able to bind more complex drugs. The improved binding capacity of these new modified CDs with the model drug 6alpha-methylprednisolone is reported.