Robert R. Conley

Clinical spectrum of the osmotic-controlled release oral delivery system (OROS*), an advanced oral delivery form

ABSTRACT Background: The osmotic-controlled release oral delivery system, OROS, is an advanced drug delivery technology that uses osmotic pressure as the driving force to deliver pharmacotherapy, usually once-daily, in several therapeutic areas. Objective: The purpose of this review is to discuss the evolution of OROS technology and examine the many therapeutic areas where OROS products are being used. Methods: A search of Medline and EMBASE were performed using the keywords ‘OROS’ and ‘osmotic delivery’ for the period January 1990 to June 2005. Data were also obtained from the manufacturers’ websites and associated publications. Results: OROS technology has evolved over the last 30 years, resulting in four systems: the elementary osmotic pump; the two-layer osmotic push–pull tablet; the advanced longitudinally compressed tablet multilayer formulation; and, the L-OROS system. OROS technology is employed for drug delivery in many therapeutic areas including: cardiovascular medicine, endocrinology, urology, and central nervous system (CNS) therapeutics. Two calcium channel blockers utilizing OROS technology for the treatment of hypertension are nifedipine and verapamil. Glipizide extended-release is used for the treatment of type 2 diabetes. Doxazosin is used for the treatment of benign prostatic hyperplasia, and oxybutynin for overactive bladder. Most recent developments are with drugs that affect the CNS, including the use of methylphenidate for treatment of attention deficit hyperactivity disorder, paliperidone extended-release and OROS hydromorphone, which are under clinical development for schizophrenia and chronic pain, respectively. Conclusions: Drug delivery using the various OROS products can result in an improved safety profile, stable drug concentrations, uniform drug effects, and reduced dosing frequency. OROS technology has also enabled the use of an effective starting dose, without the need for dose titration, which allows the achievement of symptom control much earlier than that observed with immediate-release preparations. Such attributes can enhance patient compliance and convenience, thereby ensuring efficacy and improving patient outcomes.

Proinflammatory cytokines in the prefrontal cortex of teenage suicide victims

Teenage suicide is a major public health concern, but its neurobiology is not well understood. Proinflammatory cytokines play an important role in stress and in the pathophysiology of depression-two major risk factors for suicide. Cytokines are increased in the serum of patients with depression and suicidal behavior; however, it is not clear if similar abnormality in cytokines occurs in brains of suicide victims. We therefore measured the gene and protein expression levels of proinflammatory cytokines interleukin (IL)-1β, IL-6, and tissue necrosis factor (TNF)-α in the prefrontal cortex (PFC) of 24 teenage suicide victims and 24 matched normal control subjects. Our results show that the mRNA and protein expression levels of IL-1β, IL-6, and TNF-α were significantly increased in Brodmann area 10 (BA-10) of suicide victims compared with normal control subjects. These results suggest an important role for IL-1β, IL-6, and TNF-α in the pathophysiology of suicidal behavior and that proinflammatory cytokines may be an appropriate target for developing therapeutic agents.

Treatment-resistant schizophrenic patients respond to clozapine after olanzapine non-response

BACKGROUND Treatment-resistance in schizophrenia remains a public health problem. Clozapine has been shown to be effective in about one third of this population, but carries with it medical risks and weekly blood draws. As olanzapine is a drug with a very similar biochemical profile to clozapine, it is important to evaluate whether non-response to olanzapine predicts clozapine non-response. METHODS Forty-four treatment-resistant patients received eight weeks of olanzapine, either in a double-blind trial or subsequent open treatment at a mean daily dose of 25 mg/day. Two of 44 patients (5%) responded to olanzapine treatment. Patients who did not respond could then receive clozapine. Twenty-seven subsequently received an 8-week open trial of clozapine. RESULTS Patients who did and did not receive clozapine did not differ demographically or in psychopathology. Eleven of 27 (41%) met a priori response criteria during clozapine treatment (mean dose 693 mg/day) after failing to respond to olanzapine. CONCLUSIONS This study demonstrates that failure to respond to olanzapine treatment does not predict failure to clozapine. Treatment-resistant patients who fail on olanzapine may benefit from a subsequent trial of clozapine.

Brain-derived neurotrophic factor and tyrosine kinase B receptor signalling in post-mortem brain of teenage suicide victims

Teenage suicide is a major public health concern, but its neurobiology is not very well understood. Stress and major mental disorders are major risk factors for suicidal behaviour, and it has been shown that brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (TrkB) are not only regulated by stress but are also altered in these illnesses. We therefore examined if BDNF/TrkB signalling is altered in the post-mortem brain of teenage suicide victims. Protein and mRNA expression of BDNF and of TrkB receptors were determined in the prefrontal cortex (PFC), Brodmanns Area 9 (BA 9), and hippocampus obtained from 29 teenage suicide victims and 25 matched normal control subjects. Protein expression was determined using the Western blot technique; mRNA levels by a quantitative RT-PCR technique. The protein expression of BDNF was significantly decreased in the PFC of teenage suicide victims compared with normal control subjects, whereas no change was observed in the hippocampus. Protein expression of TrkB full-length receptors was significantly decreased in both PFC and hippocampus of teenage suicide victims without any significant changes in the truncated form of TrkB receptors. mRNA expression of both BDNF and TrkB was significantly decreased in the PFC and hippocampus of teenage suicide victims compared with normal control subjects. These studies indicate a down-regulation of both BDNF and its receptor TrkB in the PFC and hippocampus of teenage suicide victims, which suggests that stress and altered BDNF may represent a major vulnerability factor in teenage suicidal behaviour.

Suicide Brain Is Associated with Decreased Expression of Neurotrophins

BACKGROUND Neurotrophins mediate diverse biological responses, including maintenance and growth of neurons and synaptic plasticity in adult brain. This study examined whether suicide brain is associated with changes in the expression of neurotrophins. METHODS Messenger ribonucleic acid (mRNA) levels of nerve growth factor (NGF), neurotrophin (NT)-3, NT-4/5, and of cyclophilin and neuron-specific enolase (NSE) were measured by quantitative reverse transcriptase polymerase chain reaction, whereas protein levels of neurotrophins were determined by enzyme-linked immunosorbent assay, in prefrontal cortex (PFC) and hippocampus from 28 suicide victims and 21 control subjects. RESULTS In hippocampus of suicide subjects compared with control subjects mRNA levels of NGF (p < .001), NT-3 (p < .001), and NT-4/5 (p < .001) were decreased, whether or not they were expressed as a ratio to cyclophilin or NSE. This was accompanied by a decrease in their respective protein levels (NGF [p < .001], NT-3 [p < .001], and NT-4/5 [p < .001]). In PFC, however, mRNA (p = .001) and protein (p < .001) levels of NT-4/5 and only protein level of NGF (p < .001) were decreased; NT-3 levels were unchanged. CONCLUSIONS Given the role of neurotrophins in synaptic plasticity and maintenance of adult neurons, our findings of altered expression of neurotrophins in postmortem brain of suicide victims suggest that these molecules might play a vital role in the pathophysiology of suicide.

Elevated Cerebrospinal Fluid Lactate Concentrations in Patients with Bipolar Disorder and Schizophrenia: Implications for the Mitochondrial Dysfunction Hypothesis

BACKGROUND Evidence is accumulating that mitochondrial dysfunction is involved in the pathophysiology of bipolar disorder and schizophrenia. Cerebrospinal fluid (CSF) concentration of lactate, a product of extra-mitochondrial glucose metabolism, is commonly elevated in individuals with mitochondrial disorders, especially those with neuropsychiatric symptoms. We tested the hypothesis that patients with bipolar disorder and schizophrenia would, on average, have elevated CSF lactate concentrations compared with healthy control subjects. METHODS The CSF lactate and CSF and plasma glucose concentrations were measured with a YSI (YSI, Yellow Springs, Ohio) 2300 STAT Plus Glucose & Lactate Analyzer in 15 samples from each of three groups of subjects: bipolar I disorder patients, schizophrenic patients, and healthy control subjects. RESULTS Mean CSF lactate concentrations were significantly higher in bipolar (1.76 +/- .38) and schizophrenic subjects (1.61 +/- .31) compared with control subjects (1.31 +/- .21 mmol/L). These differences persisted after adjusting means for CSF glucose concentration, which correlated positively with CSF lactate concentration. CONCLUSIONS This is the first report of increased CSF lactate concentrations in patients with bipolar disorder and schizophrenia. Elevated CSF lactate indicates increased extra-mitochondrial and anaerobic glucose metabolism and is consistent with impaired mitochondrial metabolism. Measuring CSF lactate concentration might help identify bipolar and schizophrenic patients with mitochondrial dysfunction who might benefit from research to elucidate and ultimately rectify possible mitochondrial pathology underlying these disorders.

First-episode schizophrenia: a focus on pharmacological treatment and safety considerations.

Schizophrenia is a debilitating disorder, which is usually chronic, and is one of the most devastating medical illnesses. Early and appropriate treatment with antipsychotics is an important strategy for patients with first-episode schizophrenia. However, there are many possible safety issues for patients with schizophrenia that should be considered and properly addressed.Depressive symptoms and suicidal behaviour commonly occur in first-episode schizophrenic patients, and every effort should be made to treat and minimise these symptoms. There are also important issues and considerations in young and first-episode patients that should also be considered in the emergency treatment setting and for minimising medication nonadherence in this population. Most importantly, adverse effects should be considered, minimised and addressed. While first- and second-generation antipsychotics (SGAs) both appear to offer similar efficacy for amelioration of positive symptoms in first-episode patients, SGAs may offer better tolerability, specifically regarding extrapyramidal symptoms (EPS) and tardive dyskinesia risk, and some prolactin-sparing benefits. However, these medications do cause a host of adverse effects, including weight gain, metabolic disturbances, corrected QT interval prolongation and prolactin-related adverse effects, which are important considerations relating to both the short- and long-term safety of patients with schizophrenia being treated with SGAs. Clozapine and olanzapine are most likely to cause weight gain and metabolic effects, while risperidone is more likely to cause EPS and prolactin elevations. Most antipsychotics should be used in low doses to minimise adverse effects and each medication should be optimised in a highly individualised way to maximise adherence and treatment outcomes and minimise tolerability and safety concerns. At some point in their lives, these patients will most probably experience periods of depression, suicidal behaviours, adverse effects and nonadherence, and every effort should be made to minimise or prevent these from occurring. Thus, safety concerns in this group of young patients, in the beginning of their first psychotic episode, are a major issue as they are starting a journey of antipsychotic treatment that is likely to last for the remainder of their lives.

ERK MAP kinase signaling in post-mortem brain of suicide subjects: differential regulation of upstream Raf kinases Raf-1 and B-Raf

The Raf kinases Raf-1 and B-Raf are upstream activators of the extracellular signal-regulated kinase (ERK)-signaling pathway and therefore participates in many physiological functions in brain, including neuronal survival and synaptic plasticity. Previously, we observed that activation of ERK-1/2, the downstream component of ERK signaling, is significantly reduced in post-mortem brain of suicide victims. The present study was undertaken to further examine whether suicide brain is also associated with abnormalities in upstream molecules in ERK signaling. The study was performed in prefrontal cortex (PFC) and hippocampus obtained from 28 suicide victims and 21 normal controls. mRNA levels of Raf-1, B-Raf, and cyclophilin were measured by quantitative RT-PCR. Protein levels of Raf-1 and B-Raf were determined by Western blot, whereas their catalytic activities were determined by immunoprecipitation and enzymatic assays. It was observed that the catalytic activity of B-Raf was significantly reduced in PFC and hippocampus of suicide subjects. This decrease was associated with a decrease in its protein, but not mRNA, level. On the other hand, catalytic activity, and mRNA and protein levels, of Raf-1 were not altered in post-mortem brain of suicide subjects. The observed changes were not related to confounding variables; however, Raf-1 showed a negative correlation with age. Also, the changes in B-Raf were present in all suicide subjects, irrespective of psychiatric diagnosis. Our results of selective reduction in catalytic activity and expression of B-Raf but not Raf-1 suggest that B-Raf may be playing an important role in altered ERK signaling in brain of suicide subjects, and thus in the pathophysiology of suicide.

Direct determination of dopamine D4 receptors in normal and schizophrenic postmortem brain tissue: A [3H]NGD-94-1 study

Using an indirect subtraction binding technique and human postmortem tissue, several laboratories1–3 reported finding increases in dopamine D4 receptors in caudate nuclei of schizophrenic patients, although others4–6 have not replicated these findings. NGD-94-1 is a selective D4 antagonist with low affinity for the D2 and D3 receptors.7,8 [3H]NGD-94-1 has been used in this study to directly determine the density of D4 receptors in normals (n = 13) and schizophrenic subjects (n = 7) off antipsychotic drugs for at least 3 months prior to death, or on antipsychotic (n = 7) drugs at the time of death. Human postmortem coronal brain sections were incubated with [3H]NGD-94-1 and autoradiograms developed; and binding in pertinent regions was quantified. In normals, the highest density of [3H]NGD-94-1 binding was in the hippocampus (68 fmol mg−1, temporal (33), insular (30), and entorhinal cortices (24.9). Significant increases in [3H]NGD-94-1 density in schizophrenics (n = 14) vs normals (n = 13) were observed in the entorhinal cortex (46%) at both low and high magnifications. The increases observed in the schizophrenics were found in both schizophrenics off antipsychotic drugs for at least 3 months prior to death and those on antipsychotic drugs at the time of death. Thus, the changes may be disease-related and not a consequence of pharmacological treatment. No significant differences were found between the two schizophrenic groups in any brain area studied.

Interstitial cells of the white matter in the dorsolateral prefrontal cortex in deficit and nondeficit schizophrenia.

An increased density of neurons in the white matter of the neocortex has been found in schizophrenia, and the original reports suggested this abnormality was restricted to a subgroup of patients. In a study of the inferior parietal cortex, we found that deficit schizophrenia subjects, but not nondeficit subjects, had an increased density of ICWMs. We extended that finding by comparing the density of microtubule-associated protein 2-immunoreactive ICWMs in deficit schizophrenia (N = 3), nondeficit schizophrenia (N = 4), and control (N = 5) subjects, using postmortem tissue from the dorsolateral prefrontal cortex (Brodmann area 46). The deficit group differed significantly from the other two groups; the respective mean (SD) density values for the deficit, nondeficit, and control groups were 1.27 (.10), .53 (.39), and .76 (.20) cells per 10−6 cubic microns. These group differences provide further evidence that deficit and nondeficit schizophrenia differ in their pathophysiology.