Cyclosporine A delivery to the eye: A comprehensive review of academic and industrial efforts.

Local ocular delivery of cyclosporine A (CsA) is the preferred method for CsA delivery as a treatment for ocular inflammatory diseases such as uveitis, corneal healing, vernal keratoconjunctivitis and dry eye disease. However, due to the large molecular weight and hydrophobic nature of CsA and the natural protective mechanisms of the eye, achieving therapeutic levels of CsA in ocular tissues can be difficult. This review gives a comprehensive overview of the current products available to clinicians as well as emerging drug delivery solutions that have been developed at both the academic and industry levels.

Influence of adolescent heavy session drinking on the systemic and brain innate immune system.

AIMS: The aim of the study was to evaluate rat models of intermittent alcohol abuse (heavy session/'heavy session' drinking) in relation to inflammatory changes in specific brain regions as well as in the periphery. Furthermore, the study was aimed to assess whether there are inflammatory changes in the blood of human intermittent alcohol abusers who might be associated with changes in neuronal circuitry in the brain, as assessed by functional magnetic resonance imaging (fMRI), which cause adverse effects on memory and learning. METHODS: Various regimes of intermittent alcohol administration have been used in rat models, which vary with respect to the dose and duration of ethanol administration as well as the time of abstinence. Immunohistological methods were used to identify activated microglia in specific brain regions. The response of isolated alveolar macrophages to in vitro stimuli was assessed by the assay of nitric oxide and the pro-inflammatory cytokines IL-6 and TNFα. Blood samples were collected from university students who had been heavy session drinkers for 2 years to assess whether there was an inflammatory cytokine profile that correlated with cognitive test scores as well as fMRI findings. RESULTS: The extent of microglia activation appears to depend on the doses and duration of ethanol administration. In addition, there is activation of phagocytic cells in the periphery, e.g. alveolar macrophages, in the rat models of heavy session drinking. Changes in the plasma levels of pro- and anti-inflammatory cytokines were present in heavy session drinking students, although no changes were identified in specific cognitive tests (which may be because of compensatory changes in the prefrontal cortex, as identified by fMRI). CONCLUSION: Changes in the cytokine levels induced by intermittent ethanol abuse may provoke inflammatory pathways in specific brain regions, such as hippocampus and prefrontal cortex (particularly during the stage of active neurogenesis in the adolescent brain), which might induce cognitive impairment in susceptible individuals.

Benefits of cetalkonium chloride cationic oil-in-water nanoemulsions for topical ophthalmic drug delivery.

OBJECTIVES: Topical ocular administration is the most convenient route of administration of drugs for the treatment of eye diseases. However, the bioavailability of drugs following eye instillations of eye drops is very low. Over the past 20 years, extensive efforts have been put into research to improve drug bioavailability without compromising treatment compliance and patients' quality of life. KEY FINDINGS: One of the most efficient ways to improve drug bioavailability is to increase the precorneal residence time of the eye drop formulations. As a result, new eye drops, with bioadhesive properties, have been developed based on the cationic oil-in-water (o/w) nanoemulsion technology. These low viscosity eye drop nanoemulsions have improved precorneal residence time through the electrostatic interactions between the positively charged oil nanodroplets and the negatively charged ocular surface epithelium. SUMMARY: This review is the first to present the benefits of this new strategy used to improve ocular drug bioavailability. The roles of the cationic agent in the stabilization of a safe cationic o/w nanoemulsion have been discussed, as well as the unexpected benefits of the cationic o/w nanoemulsion for the protection and restoration of a healthy tear film and corneal epithelium.

Increased cortical activity in binge drinkers during working memory task: a preliminary assessment through a functional magnetic resonance imaging study.

BACKGROUND: Cerebral dysfunction is a common feature of both chronic alcohol abusers and binge drinkers. Here, we aimed to study whether, at equated behavioral performance levels, binge drinkers exhibited increased neural activity while performing simple cognitive tasks. METHODS: Thirty-two participants (16 binge drinkers and 16 matched controls) were scanned using functional magnetic resonance imaging (fMRI) while performing an n-back working memory task. In the control zero-back (N0) condition, subjects were required to press a button with the right hand when the number "2" was displayed. In the two-back (N2) condition, subjects had to press a button when the displayed number was identical to the number shown two trials before. RESULTS: fMRI analyses revealed higher bilateral activity in the pre-supplementary motor area in binge drinkers than matched controls, even though behavioral performances were similar. Moreover, binge drinkers showed specific positive correlations between the number of alcohol doses consumed per occasion and higher activity in the dorsomedial prefrontal cortex, as well as between the number of drinking occasions per week and higher activity in cerebellum, thalamus and insula while performing the N2 memory task. CONCLUSIONS: Binge alcohol consumption leads to possible compensatory cerebral changes in binge drinkers that facilitate normal behavioral performance. These changes in cerebral responses may be considered as vulnerability factors for developing adult substance use disorders.

Distribution of cyclosporine A in ocular tissues after topical administration of cyclosporine A cationic emulsions to pigmented rabbits.

PURPOSE: The aim of this study was to compare the ocular and systemic distribution of cyclosporine A (CsA) in rabbits after the instillation of preservative-free CsA cationic and anionic emulsions. METHODS: For the single-dose pharmacokinetic (PK) study, rabbits were instilled with 50 µL of the test material. For the multiple-dose PK study, rabbits were instilled twice daily with Restasis or once daily with NOVA22007 for 10 days. At each time point, the cornea, conjunctiva, and whole blood were harvested for CsA quantification. Ocular and systemic distribution were determined after 4 times daily instillations with 50 µL of 3H-CsA cationic and anionic emulsions for 7 days. Restasis was used as a reference in all studies. RESULTS: Single-dose PK data demonstrated that NOVA22007 0.1% and 0.05% delivered higher CsA concentrations to the cornea than Restasis [concentration maximum (C max): 2692, 1372, and 748 ng/g, respectively] and have a better exposition (area under the curve). Conjunctival Cmax values were 1914, 696, and 849 ng/g and area under the curve values were 3984, 2796, and 2515 ng/g · h, for either dose of the cationic emulsions and Restasis, respectively. The multiple-dose PK and the 3H-CsA distribution data demonstrated that the systemic distribution after repeated instillations was low and comparable for all emulsions. CONCLUSIONS: These data demonstrate that the CsA cationic emulsions were more effective than Restasis at delivering CsA to target tissues, thus confirming the potential advantage of cationic emulsions over anionic emulsions as vehicle for ocular drug delivery for the treatment of ocular surface diseases.

Successfully improving ocular drug delivery using the cationic nanoemulsion, novasorb.

Topical ophthalmic delivery of active ingredients can be achieved using cationic nanoemulsions. In the last decade, Novagali Pharma has successfully developed and marketed Novasorb, an advanced pharmaceutical technology for the treatment of ophthalmic diseases. This paper describes the main steps in the development of cationic nanoemulsions from formulation to evaluation in clinical trials. A major challenge of the formulation work was the selection of a cationic agent with an acceptable safety profile that would ensure a sufficient ocular surface retention time. Then, toxicity and pharmacokinetic studies were performed showing that the cationic emulsions were safe and well tolerated. Even in the absence of an active ingredient, cationic emulsions were observed in preclinical studies to have an inherent benefit on the ocular surface. Moreover, clinical trials demonstrated the efficacy and safety of cationic emulsions loaded with cyclosporine A in patients with dry eye disease. Ongoing studies evaluating latanoprost emulsion in patients with ocular surface disease and glaucoma suggest that the beneficial effects on reducing ocular surface damage may also extend to this patient population. The culmination of these efforts has been the marketing of Cationorm, a preservative-free cationic emulsion indicated for the symptomatic treatment of dry eye.

Binge drinking +/- chronic nicotine administration alters extracellular glutamate and arginine levels in the nucleus accumbens of adult male and female Wistar rats.

AIMS: The effect of 'binge drinking' coupled or not with chronic nicotine administration on nucleus accumbens (NAc) glutamate, arginine, taurine and hydroxyl radical levels has been investigated in these present studies. METHODS AND RESULTS: Ethanol, 2 or 3 g/kg, has been administered to male or female adult rats in a 'binge-type' regime for 3 weeks, +/- nicotine, and changes in glutamate, arginine and taurine content in the NAc, assayed by microdialysis after a further dose of ethanol. The basal concentration of NAc glutamate increased 8-fold in the female adult rats but did not change significantly after further doses of ethanol. In contrast, the male adult rats showed no changes in basal glutamate content but exhibited a dose-dependent increase in NAc glutamate after further doses of ethanol. NAc arginine basal levels decreased significantly in both male and female adult rats after further doses of ethanol. Co-administration of nicotine modified the toxicity of ethanol as exemplified by diminishment of both the basal NAc glutamate release as well as modifying the release of this excitatory amino acid after further ethanol doses, particularly in female rats. In addition, the marked changes in arginine release after further ethanol doses were less evident. There was no evidence for increased hydroxyl radical production in the NAc after 'binge drinking' +/- nicotine. CONCLUSION: There appeared to be a greater vulnerability to ethanol toxicity in female adult rats after 'binge drinking'. It remains unclear whether the increased release of glutamate during the microdialysis evokes activation of inducible nitric oxide synthase (iNOS), which would utilize arginine in the formation of nitric oxide.

Anti-inflammatory actions of a taurine analogue, ethane ß-sultam, in phagocytic cells, in vivo and in vitro.

The ability of a taurine prodrug, ethane ß-sultam, to reduce cellular inflammation has been investigated, in vitro, in primary cultures of alveolar macrophages and an immortilised N9 microglial cell line and in vivo in an animal model of inflammation and control rats. Ethane ß-sultam showed enhanced ability to reduce the inflammatory response in alveolar macrophages, as assayed by the lipopolysaccharide-stimulated-nitric oxide release, (LPS stimulated-NO), in comparison to taurine both in vitro (10 nM, 50 nM) and in vivo (0.15 mmol/kg/day by gavage). In addition, ethane ß-sultam, (50, 100 and 1000 nM) significantly reduced LPS-stimulated glutamate release from N9 microglial cells to a greater extent than taurine. The anti-inflammatory response of taurine was shown to be mediated via stabilisation of IkBα. The use of a taurine prodrug as therapeutic agents, for the treatment of neurological conditions, such as Parkinson's and Alzheimer's disease and alcoholic brain damage, where activated phagocytic cells contribute to the pathogenesis, may be of great potential.

Neuro-inflammation induced in the hippocampus of 'binge drinking' rats may be mediated by elevated extracellular glutamate content.

The neuropathological and immune changes induced in the brain by 'binge drinking' have been investigated in a rat model. Evidence of neuro-inflammation was identified in the 'binge drinking' rat model of alcohol abuse after 3 weeks of administration of 2 or 3 g/kg ethanol (EtOH), three times per day for two consecutive days, followed by 5 days of abstinence: Firstly, alveolar macrophages, isolated from these animals, showed significant increases in inducible nitric oxide synthase, as assayed by nitrite release, both before and after lipopolysaccaharide stimulation. Secondly, significant numbers of activated microglia were present in the dentate gyrus region of the hippocampus of the 'binge drinking' model, after major histocompatibility complex class II staining, by comparison with the control. Microdialysis studies in the ventral hippocampus identified a significant increase in the basal extracellular concentration of glutamate, in both the 2 and 3 g/kg administered 'binge drinking' rats. In contrast, no changes in the hippocampal extracellular concentrations, of GABA and taurine, or the dopamine and serotonin metabolites were observed under basal conditions. A further dose of EtOH induced a significant decrease in the concentrations of both 3,4-dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid, whereas glutamate, taurine and GABA levels were unaffected. There was no evidence that EtOH preference was initiated by the 'binge drinking' regimen. Our results suggest that the possible toxicity associated with 'binge drinking' maybe directed by the elevated glutamate levels, which in turn, activate phagocytic cells to release their inflammatory cytokines and chemokines, ultimately leading to neuro-inflammation.

The influence of chronic nicotine administration on behavioural and neurochemical parameters in male and female rats after repeated binge drinking exposure.

AIMS: The possible interaction between nicotine and 'binge drinking' in eliciting changes in behavioural patterns of 'binge drinking' rats as well as nucleus accumbens (NAc) glutamate levels has been investigated in these present studies. METHODS: Adult or adolescent male and female rats received ethanol, 2 g/kg or 3 g/kg, by gavage in a 'binge drinking' regimen (3 times/day over a 6 h period, for 2 days followed by 5 days of abstinence) combined with or without nicotine, 0.3 g/kg, for either a 5-week (adult) or a 4-week (adolescent) period. Motor activity was then assessed for a period of 60 min after three further doses of ethanol or water. In addition, the NAc glutamate level was assayed in each group for 1 h after the first gavage regimen with ethanol, 2 g/kg or 3 g/kg, or water. RESULTS: Adult female rats showed greater sensitivity to each ethanol dose (2 g/kg and 3 g/kg) than the adult male rats, their motor activity decreasing during the first and third 'binge'. In contrast, in male adult rats, the sedative effects of ethanol were reduced, particularly after the third binge when no significant changes in the locomotor activity were apparent between the ethanol-administered male rats and controls. Adolescent rats did differ in their response to ethanol in comparison with adult rats. It was noteworthy that in young female adolescent rats, given 2 g/kg ethanol, motor activity was enhanced, thereby indicating that adolescent female rats are less sensitive to the sedative effects of ethanol at specific doses. In addition, male and female adolescent rats showed little change in locomotor activity in comparison with controls during the third 'binge administration' possibly indicating that tolerance to such alcohol doses was occurring. Nicotine administration did prevent the decrease in locomotor activity after ethanol administration during the first binge regimen in both male and female adolescents as well as adult female rats. However, after the third binge, such alcohol-induced changes in motor activity were not so well defined in the female adult rats that now showed significant decreases in motor activity. In contrast, adolescent male and female rats still showed similar motor activity to that of the controls. No clear association between the NAc glutamate extracellular content and locomotor activity was discernible in either adult or adolescent rats in these present studies. However, chronic nicotine administration markedly reduced the elevated basal glutamate content in the 'binge drinking female' adult rats. CONCLUSIONS: These studies have shown clear and distinct differences, with respect to both sensitivity and tolerance, in adult and adolescent male and female rats, which could be modified by supplementation with nicotine.

Biochemical and neurotransmitter changes implicated in alcohol-induced brain damage in chronic or 'binge drinking' alcohol abuse.

The brain damage, which occurs after either chronic alcoholization or binge drinking regimes, shows distinct biochemical and neurotransmitter differences. An excessive amount of glutamate is released into specific brain regions during binge drinking (in excess of 4- to 5-fold of the normal basal concentration) that is not evident during periods of excessive alcohol consumption in chronic alcohol abusers. Increases in glutamate release are only observed during the initial stages of withdrawal from chronic alcoholism ( approximately 2- to 3-fold) due to alterations in the sensitivities of the NMDA receptors. Such changes in either density or sensitivity of these receptors are reported to be unaltered by binge drinking. When such excesses of glutamate are released in these two different models of alcohol abuse, a wide range of biochemical changes occur, mediated in part by increased fluxes of calcium ions and/or activation of various G-protein-associated signalling pathways. Cellular studies of alveolar macrophages isolated from these two animal models of alcohol abuse showed enhanced (binge drinking) or reduced (chronic alcoholization) lipopolysaccharide (LPS)-stimulated NO release. Such studies could suggest that neuroadaptation occurs with the development of tolerance to alcohol's effects in both neurotransmitter function and cellular processes during chronic alcoholization that delay the occurrence of brain damage. In contrast, 'binge drinking' induces immediate and toxic effects and there is no evidence of an increased preference for alcohol as seen after withdrawal from chronic alcoholization.

Neurochemical pathways involved in the protective effects of nicotine and ethanol in preventing the development of Parkinson's disease: potential targets for the development of new therapeutic agents.

In this short review, neurochemical targets are identified where nicotine, and possibly ethanol, may interact to prevent the occurrence of Parkinson's disease. These are (a) the nicotinic acetycholine receptors present in the nigrostriatal area or on the surface of microglia, (b) monoamine oxidases and (c) inducible nitric oxide synthase. If such induced changes can be verified in clinical studies, this may help in the design of new therapeutic drugs which may be of relevance to diminish the incidence and perhaps the progression of the debilitating condition of Parkinson's disease.

Nicotine increases ethanol preference but decreases locomotor activity during the initial stages of chronic ethanol withdrawal.

AIM: The ability of nicotine to modify withdrawal symptoms in rats chronically treated with alcohol, with respect to locomotor activity and ethanol or nicotine preference, has been evaluated in these studies. METHODS AND RESULTS: Preliminary studies showed that locomotor activity increased 8-9 h after withdrawal from chronic nicotine intoxication, which was dose specific; it occurred in rats administered 0.15 mg/kg or 0.6 mg/kg but not the 0.3 mg/kg nicotine dose. Administration of nicotine, either acutely (0.3 mg/kg) during ethanol withdrawal, or chronically (0.15, 0.3 or 0.6 mg/kg) during the chronic alcohol treatment procedure, diminished locomotor activity, which increases significantly, approximately 6-7 h after withdrawal, in rats chronically treated with alcohol. Rats which were chronically treated with alcohol alone or in combination with nicotine, 0.3 mg/kg, showed an increase in ethanol intake when the free choice was performed between ethanol 10% and tap water; on the contrary, when the free choice was performed between ethanol 10% versus nicotine, 0.3 mg/kg, results showed a decrease in ethanol preference and a concomitant increase in nicotine preference. CONCLUSION: These studies clearly identified the modulatory effects of nicotine, at specific doses, on both motility and preference in rat chronically co-administered nicotine and ethanol.

SR147778, a CB1 cannabinoid receptor antagonist, suppresses ethanol preference in chronically alcoholized Wistar rats.

This study investigated the effect of the new CB1 cannabinoid receptor antagonist, SR147778, on ethanol preference in chronically alcoholized Wistar rats. In study 1, SR147778, at doses of 0.3, 1, or 10 mg/kg/day (mg/kg/d) intraperitonealy (ip), was administered during chronic pulmonary ethanol intoxication for 30 days. The rats were then exposed to a two-bottle choice (ethanol 10% v/v vs. water) for at least 30 days. Neither 0.3 nor 1 mg/kg/d had any effect on ethanol preference. In contrast, the high dose induced a significant transient increase in ethanol intake between days 6 and 10. In study 2, SR147778, at doses of 0.3, 1, or 10 mg/kg/d ip, was administered during the free-choice period after chronic alcoholization. Both ethanol preference and intake were significantly reduced only for 1 and 10 mg/kg/d. These results reinforce the hypothesis that the cannabinoid CB1 receptor is part of the neural substrate mediating alcohol intake and the motivational properties of alcohol. When these results are compared with those obtained with SR141716 (Rimonabant) on ethanol preference, we observed that (1) coadministration of 10 mg/kg/d SR147778 during chronic alcoholization induced a shorter transient increase of ethanol intake than Rimonabant and (2) SR147778 treatment during the free-choice period at doses of 1 and 10 mg/kg/d decreased ethanol intake more dramatically than SR141716 which, furthermore, continued for the duration of the free choice.

Nicotine-induced changes of glutamate and arginine in naive and chronically alcoholized rats: an in vivo microdialysis study.

The effects of nicotine, when administered either acutely or chronically, at doses of 0.15, 0.3 or 0.6 mg/kg, on the release of glutamate and arginine in the rat nucleus accumbens have been studied in microdialysis experiments. Glutamate release significantly increased after acute nicotine injection, 0.3 mg/kg, which was accentuated if there was a priming regime of saline for the previous 27 days. This is possibly related to the rewarding effects of nicotine. Five hours after cessation of chronic oral nicotine administration, there were significant increases in glutamate content, which was possibly reflective of a withdrawal process. Significant decreases in nucleus accumbens arginine release were evident, between 1 and 2 h, after chronic nicotine administration. When nicotine was co-administered to rats during chronic ethanol intoxication, at either 0.15 mg/kg or 0.3 mg/kg doses, glutamate release did not increase during the first 12 h of withdrawal. However, a decrease in arginine microdialysate content was still observed with all nicotine doses. The nicotine-induced changes in glutamate and arginine release in nucleus accumbens highlights the complex neuropharmacological interactions evoked by this compound and also identified its possible modulating effect on glutamate release during the initial stages of chronic ethanol withdrawal.

Production of reactive oxygen species following acute ethanol or acetaldehyde and its reduction by acamprosate in chronically alcoholized rats.

The salicylate trap method, combined with microdialysis, has been used to validate whether reactive oxygen species, particularly hydroxyl radicals, ((*)OH), are generated in the hippocampus of male Wistar rats after acute intraperitoneal administration of either ethanol, 2 and 3 g/kg, or acetaldehyde, 200 mg, or during the initial stages of ethanol withdrawal after chronic ethanol intoxication. Salicylate (5 mM) was infused into the hippocampus via the microdialysis probe and the products of its metabolism by hydroxyl radical, particularly 2,3-dihydroxybenzoic acid (2,3-DHBA) as well as 2,5-dihydroxybenzoic acid (2,5-DHBA) assayed by HPLC (High Pressure Liquid Chromatography). Acetaldehyde, 200 mg/kg, and the higher acute dose of ethanol, 3 g/kg, induced transitory increases in 2,3-DHBA and 2,5-DHBA microdialysate content. At the cessation of four weeks of chronic ethanol intoxication, (by the vapour inhalation method), the mean blood alcohol level was 1.90 g/l. Significant increases of microdialysate 2,3-DHBA and 2,5-DHBA levels were assayed 3 h after alcohol withdrawal which were sustained for a further 5 and 1 h 40 min respectively. Oral administration of Acamprosate, 400 mg/kg/day, during the chronic ethanol intoxication procedure prevented the increased formation of 2,3- and 2,5-DHBA by comparison to rats chronically ethanol intoxicated alone.

A water-soluble prodrug of cyclosporine A for ocular application: a stability study.

UNIL088 is a water-soluble prodrug of cyclosporine A (CsA) developed for topical eye delivery. Such a prodrug has to fulfil two paradoxical requirements as it must be rapidly hydrolysed under physiological conditions but also retain a long shelf-life in aqueous media. This study has been conducted to explore the stability of UNIL088 formulated as an eyedrop solution. The stability study of the prodrug was performed over a pH range of 5-7 at 20 degrees C and at various ionic strengths. The molecule was more stable at pH 5 than at pH 7 with conversion rate constant of 3.2 x 10(-3) and 26.0 x 10(-3)days(-1), respectively. The effect of temperature was studied at four different temperatures and activation energy was determined. Conversion of UNIL088 followed a pseudo-first-order kinetic with an activation energy of 79.4 kJ mol(-1). Due to its low solubility, CsA generated precipitated in the solution. The average size of CsA precipitates, determined by photon spectroscopy, was 0.22 and 1.08 microm at 7 and 14 days, respectively. The hydrolysis mechanism was partially elucidated by identification of the intermediate pSer-Sar-CsA.

Effects of CB1 cannabinoid receptor blockade on ethanol preference after chronic alcohol administration combined with repeated re-exposures and withdrawals.

AIMS: The cannabinoid CB1 receptor antagonist, SR141716A, differentially affects the ethanol preference of chronically alcoholized rats when administered during cycles of ethanol exposure and withdrawal. In this study, ethanol preference was investigated in chronically alcoholized rats that underwent regular withdrawal periods during which the brain cannabinoid CB(1) receptor antagonist, SR141716A, was administered. METHODS: The cannabinoid receptor antagonist SR141716A, 3 or 10 mg/kg/day, was administered i.p. to Wistar rats at the conclusion of a 4-week period of chronic alcoholization, as they commenced a cycle of alcohol withdrawal for 10 days followed by a period of 10 days chronic ethanol exposure. In a second set of experiments, an additional cycle of ethanol withdrawal and re-exposure was given. Preference for ethanol versus water started at the end of the first or second chronic ethanol re-exposure for a period of at least 30 days. RESULTS: In rats pretreated with the higher dose of SR141716A, ethanol preference during free choice was significantly increased after two ethanol re-exposures. In contrast, pretreatment with the lower SR141716A dose induced no significant change in ethanol intake during the free choice followed by either one or two ethanol re-exposures. CONCLUSIONS: SR141716A, 10 mg/kg/day dose, induced a significant increase in ethanol preference which was dependent on both the number of ethanol withdrawals and chronic ethanol re-exposures, while 3 mg/kg/day had no significant effect on ethanol preference.