Low Therapeutic Doses Research Articles

Ink-jet printing versus solvent casting to prepare oral films: Effect on mechanical properties and physical stability

The aim of this work was to compare and contrast the mechanical properties and physical stabilities of oral films prepared with either thermal ink-jet printing (TIJP) or solvent casting (SC). Clonidine hydrochloride was selected as a model drug because of its low therapeutic dose and films were prepared using cellulose polymers. Mechanical testing showed that the printed films had Young’s moduli and tensile strength values similar to the free film, while casted films were significantly more brittle. The drug also appeared to crystallize out of casted films during stress testing whereas printed films remained unchanged. The dissolution behavior of printed and cast films were similar, because of the rapid disintegration of the polymer. The conclusion is that printing resulted in a better film than casting because the drug resided on the film, rather than in the film where it could exert a plasticizing effect.

Effect of anagrelide on cardiac repolarization in healthy volunteers: a randomized, double‐blind, placebo‐ and positive‐controlled, thorough QT study

AbstractThe aim of this study was to assess the effect of low and high therapeutic doses of anagrelide (0.5 and 2.5 mg) on cardiac repolarization, measured by the QTcNi (individual correction) and QTcF (Fridericia's correction), compared with placebo and moxifloxacin 400 mg (positive control) in healthy subjects. In this randomized, double‐blind, crossover trial, 60 healthy volunteers were enrolled and randomized. Anagrelide 0.5 and 2.5 mg rapidly increased mean heart rate (HR) by 7.8 and 29.1 bpm respectively. For anagrelide 2.5 mg, the maximum time‐matched change (one‐sided 95% upper confidence bound) in mean QTcNi and QTcF was 13.0 msec (15.7 msec) and 10.0 msec (12.7 msec), respectively, at 1 h post dose. However, time‐matched changes in QTcNi and QTcF quickly decreased to <6 msec by 2 h post dose, despite high stable HR and high plasma concentrations of anagrelide and its active metabolite at these times. For anagrelide 0.5 mg, the maximum time‐matched change in mean QTcNi and QTcF was 7.0 msec (9.8 msec) and 5.0 msec (8.0 msec) respectively. No new safety concerns were reported. The increase in QTc interval met the definition for a positive thorough QT/QTc study only when HR was increasing rapidly, suggesting that the increased QTc may be related to the rapidly increasing HR rather than a direct effect of anagrelide plasma concentrations. However, the direct causal relationship of anagrelide on cardiac repolarization cannot be completely excluded, and caution is advised when treating patients with known risk factors for QT interval prolongation.

Chronic ingestion of H1-antihistamines increase progression of atherosclerosis in apolipoprotein E-/- mice.

Although increased serum histamine levels and H1R expression in the plaque are seen in atherosclerosis, it is not known whether H1R activation is a causative factor in the development of the disease, or is a host defense response to atherogenic signals. In order to elucidate how pharmacological inhibition of histamine receptor 1 (H1R) signaling affects atherogenesis, we administered either cetirizine (1 and 4 mg/kg. b.w) or fexofenadine (10 and 40 mg/kg. b.w) to ApoE−/− mice maintained on a high fat diet for three months. Mice ingesting a low dose of cetirizine or fexofenadine had significantly higher plaque coverage in the aorta and cross-sectional lesion area at the aortic root. Surprisingly, the higher doses of cetirizine or fexofenadine did not enhance atherosclerotic lesion coverage over the controls. The low dose of fexofenadine, but not cetirizine, increased serum LDL cholesterol. Interestingly, the expression of iNOS and eNOS mRNA was increased in aortas of mice on high doses of cetirizine or fexofenadine. This may be a compensatory nitric oxide (NO)-mediated vasodilatory mechanism that accounts for the lack of increase in the progression of atherosclerosis. Although the administration of cetirizine did not alter blood pressure between the groups, there was a positive correlation between blood pressure and lesion/media ratio at the aortic root in mice receiving the low dose of cetirizine. However, this association was not observed in mice treated with the high dose of cetirizine or either doses of fexofenadine. The macrophages or T lymphocytes densities were not altered by low doses of H1-antihistamines, whereas, high doses decreased the number of macrophages but not T lymphocytes. The number of mast cells was decreased only in mice treated with low dose of fexofenadine. These results demonstrate that chronic ingestion of low therapeutic doses of cetirizine or fexofenadine enhance progression of atherosclerosis.

300,000 IU or 600,000 IU of oral vitamin D3 for treatment of nutritional rickets: A randomized controlled trial

To evaluate the non-inferiority of a lower therapeutic dose (300,000 IU) in comparison to standard dose (600,000) IU of Vitamin D for increasing serum 25(OH) D levels and achieving radiological recovery in nutritional rickets. Randomized, open-labeled, controlled trial. Tertiary care hospital. 76 children (median age 12 mo) with clinical and radiologically confirmed rickets. Oral vitamin D3 as 300,000 IU (Group 1; n=38) or 600,000 IU (Group 2; n=38) in a single day. Primary: Serum 25(OH)D, 12 weeks after administration of vitamin D3; Secondary: Radiological healing and serum parathormone at 12 weeks; and clinical and biochemical adverse effects. Serum 25(OH)D levels [geometric mean (95% CI)] increased significantly from baseline to 12 weeks after therapy in both the groups [Group 1: 7.58 (5.50–10.44) to 16.06 (12.71– 20.29) ng/mL, P<0.001]; Group 2: 6.57 (4.66–9.25) to 17.60 (13.71–22.60, P<0.001]. The adjusted ratio of geometric mean serum 25(OH)D levels at 12 weeks between the groups (taking baseline value as co-variate) was 0.91 (95% CI: 0.65–1.29). Radiological healing occurred in all children by 12 weeks. Both groups demonstrated significant (P<0.05) and comparable fall in the serum parathormone and alkaline phosphatase levels at 12 weeks. Relative change [ratio of geometric mean (95% CI)] in serum PTH and alkaline phosphatase, 12 weeks after therapy, were 0.98 (0.7–1.47) and 0.92 (0.72–1.19), respectively. The serum 25(OH)D levels were deficient (<20 ng/mL) in 63% (38/60) children after 12 weeks of intervention [Group 1: 20/32 (62.5%); Group 2: 18/28 (64.3%)]. No major clinical adverse effects were noticed in any of the children. Hypercalcemia was documented in 2 children at 4 weeks (1 in each Group) and 3 children at 12 weeks (1 in Group 1 and 2 in Group 2). None of the participants had hypercalciuria or hypervitaminosis D. A dose of 300,000 IU of vitamin D3 is comparable to 600,000 IU, administered orally, over a single day, for treating rickets in under-five children although there is an unacceptably high risk of hypercalcemia in both groups. None of the regime is effective in normalization of vitamin D status in majority of patients, 3 months after administering the therapeutic dose.

Gastric Intestinal Metaplasia and Tamoxifen: Can We Reverse the Inevitable?

Gastric intestinal metaplasia can occur after chronic infection with Helicobacter pylori and is considered a precursor of gastric adenocarcinoma. Thus, interventions which can reverse intestinal metaplasia may reduce the incidence of gastric cancer. The manuscript by Moon et al. published in this issue of Digestive Diseases and Sciences [1] reports somewhat surprising results suggesting that Korean women receiving chronic tamoxifen treatment after breast cancer surgery showed a decrease in intestinal metaplasia. Previous work from the Mills laboratory had shown that high doses of tamoxifen treatment in mice led to loss of parietal cells and the evolution of Spasmolytic Polypeptide Expressing Metaplasia (SPEM). Nevertheless, in patients receiving lower therapeutic doses of tamoxifen for an extended period, the findings of Moon et al. indicate that tamoxifen may in fact impair progression of metaplasia to intestinal metaplasia. Importantly, since patients taking aromatase inhibitors did not alter the extent of intestinal metaplasia, the tamoxifen effects observed are likely due to an off-target effect rather than one associated with estrogen receptor blockade. Previous investigations have noted off-target effects of tamoxifen at various levels including alterations in calcium signaling [2], ceramide metabolism [3] and the parietal cell protonophore activities previously proposed by the Mills laboratory [4]. Thus, while it is difficult to define the mechanisms that may be responsible for the observed mucosal alterations in this treatment cohort, the results are nevertheless encouraging for the development of interventions which alter the natural history of metaplasia in the stomach. The authors acknowledge the limitations of this retrospective study. A critical question left by these studies focuses on the impact of tamoxifen treatment on the mucosal lineages. While the report demonstrates that women receiving tamoxifen have a reduced amount of intestinal metaplasia, it is not at all clear that the loss of intestinal metaplasia leads to re-establishment of a normal mucosa. Recent investigations have supported the concept that loss of parietal cells initiated by H. pylori infection leads initially to the development of Spasmolytic Polypeptide Expressing Metaplasia (SPEM) and then over time SPEM evolves into intestinal metaplasia [5]. Unfortunately, the present study did not examine either the state of remaining atrophy or the presence of SPEM in tamoxifentreated patients. Interestingly, the progression of metaplasia from SPEM to intestinal metaplasia and neoplasia may be driven by inflammatory cells, especially macrophages [6]. Indeed, alterations in inflammatory cell response are the most likely explanation for the off-target influences of tamoxifen. While the data in the present study suggest that the inflammation scores were not significantly improved by tamoxifen treatment, there is no way to judge whether this qualitative determination would reflect changes in macrophage subsets. Further studies will need to address possible effects of tamoxifen treatment on inflammatory cell function. Since intestinal metaplasia is considered the critical precursor lesion for the development of gastric adenocarcinoma, the reversibility of metaplastic lesions is of considerable interest. Some investigations have suggested eradication of H. pylori may ameliorate or even reverse intestinal metaplasia, but other studies have found significant numbers of patients who retain intestinal metaplasia J. R. Goldenring (&) Epithelial Biology Center and Section of Surgical Science, Vanderbilt University Medical Center, 10435-G MRB IV, 2213 Garland Avenue, Nashville, TN 37232, USA e-mail: jim.goldenring@vanderbilt.edu

Nandrolone decanoate inhibits gluconeogenesis and decreases fasting glucose in Wistar male rats

The use of anabolic-androgenic steroids to improve physical performance or appearance has increased notably. The doses used are 10- to 100- fold higher than the therapeutic dose (TD), and this abuse can cause several side effects. Glucose metabolism is significantly affected by anabolic-androgenic steroid abuse, but studies about glycemic regulation during fasting are scarce. There are some evidences showing that testosterone can antagonize glucocorticoids action, which are crucial to glucose production during fasting. Thus, the aim of this study was to determine the impact of supraphysiological doses (SDs) of nandrolone decanoate (DECA) on rat glucose metabolism during fasting. Male Wistar rats were treated with i.m. injections of vehicle, a low TD (0.016 mg/100 g b.w.-TD group) or a high SD (1 mg/100 g b.w.-SD group) of DECA, once a week for 8 weeks. After 12 h fasting, we evaluated glucose and pyruvate tolerance tests, liver glycogen content, serum levels of gluconeogenic substrates, insulin and corticosterone, glucose uptake and hexokinase (HK) activity in skeletal muscle, and the adrenal catecholamine content. SD group had increased serum insulin levels and a blunted response to insulin regarding glucose uptake in skeletal muscle. Fasting serum glucose decreased significantly in SD group, as well as the pyruvate tolerance test and liver glycogen content. Moreover, serum levels of glycerol were increased in SD group. Our data indicate that SDs of DECA exert effects on different regulatory points of glucose metabolism, resulting in defective gluconeogenesis and decreased skeletal muscle glucose uptake in response to insulin.

Impact of antidepressant drug clomipramine on hepatorenal functions, lipid peroxidation, micronucleus frequencies and DNA damage using an alkaline comet assay

Clomipramine is a tricyclic antidepressant commonly used to treat anxiety related behavioral disorders in human and animals. The current study was performed to assess the effects of different therapeutic doses of clomipramine hydrochloride supplementation on hepato-renal functions, lipid peroxidation, frequencies of micronucleated polychromatic erythrocytes in bone marrow, DNA damage in peripheral blood lymphocytes using the comet assay and effects of withdrawal of the drug for 4 weeks on these parameters. Forty two Swiss albino male mice were divided into seven equal groups. The first group served as a control, while groups 2, 4 and 6 were orally treated with low (75 mg/kg of body weight), medium ((100 mg/kg of body weight), and high doses (250 mg/kg of body weight), respectively of clomipramine hydrochloride daily for 30 days. However, groups 3, 5 and 7 served as low, medium and high withdrawal groups for 4 weeks. Different therapeutic doses of clomipramine hydrochloride resulted in a significant increase in the levels of serum ALT, AST, BUN and creatinine compared to control. Also, plasma malondialdehyde levels showed were significant increase in mice treated by different therapeutic doses of clomipramine hydrochloride compared to control group. In contrast, the administration of clomipramine hydrochloride in three therapeutic doses for 30 days caused a significant increase in the frequency of micronuclei in polychromatic erythrocytes of mice bone marrow, this increase reached more than ten times the value determined before the treatment and directly proportional to the dose. The level of basal endogenous DNA damage measured as the mean of percentage of DNA in the tail of the lymphocytes in mice treated by low, medium and high therapeutic doses of clomipramine hydrochloride were significantly higher than in controls. However, in the recovery period (4weeks), a significant amelioration in all studied parameters was observed. Results indicated that, clomipramine is a hepato renal toxic drug and induces a significant amount of DNA damage and in-vivo genotoxic drug.

Microtubule‐stabilizing agents delay the onset of EAE through inhibition of migration

We have shown previously that microtubule-stabilizing agents (MSA), a class of anti-proliferative compounds, can delay disease onset and reduce cumulative disease in an experimental model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). To explore how MSA could alter EAE disease processes, we compared the effect of administering MSA before or after peak antigen-specific proliferation and found that treatment before proliferation completely inhibited antigen-specific responses in the spleen; whereas administration of an MSA such as paclitaxel or docetaxel after peak proliferation did not. Despite the presence of antigen-specific responses in mice treated at the later time point, both treatment periods resulted in similar protection against EAE, suggesting that the protective effect of MSA in EAE could not be solely attributed to anti-proliferative activity. Instead, using in vivo migration assays, it was shown that MSA inhibit immune cell infiltration into the central nervous system (CNS). Furthermore, we found that the efficacy of an MSA could be enhanced by administering low doses of two different MSA together, such as peloruside A and ixabepilone, indicating that these MSA synergize in vivo to suppress disease. Taken together, these data suggest that MSA can suppress EAE by at least two distinct mechanisms of action--prevention of proliferation and inhibition of migration into the CNS. Finally, we have shown that a combination treatment with synergizing MSA may provide enhanced protection at lower therapeutic doses.

Impulse Control Disorder in a Patient on Long-Term Treatment With Bromocriptine for a Macroprolactinoma

Impulse control disorders (ICDs) constitute socially disruptive behaviors such as pathological gambling, impulsive eating, compulsive shopping, and hypersexuality. These conditions are well recognized in patients on dopamine agonist (DA) therapy for Parkinson disease. Dopamine agonists are widely used as first-line agents in the treatment of prolactinomas, but ICDs in this group of patients are relatively rare, perhaps because of lower therapeutic doses used. A review of the literature yielded only a few cases of ICDs in patients on DA treatment for prolactinomas. These symptoms are perhaps underreported because of lack of awareness among patients and health care professionals. Impulse control disorders are recognized psychiatric disorders that have significant psychological and social implications, and patients need to be counselled about this rare possibility when embarking on prolonged DA therapy. We describe a young patient with severe, socially disruptive impulsivity manifesting with pathological gambling who had been on long-term bromocriptine therapy for a macroprolactinoma.

A study of the combination of triamcinolone and 5-fluorouracil in modulating keloid fibroblasts in vitro

Preliminary clinical trials suggest a superior effect when steroids and 5-fluorouracil are injected together for the intralesional therapy of keloids. In addition, it has been proposed that low-dose 5-fluorouracil may have advantages over conventional high dosages. We explored the molecular basis for the potential synergy involved in the combined treatment with triamcinolone and 5-fluorouracil. The effects of triamcinolone alone or in combination with low-dose 5-fluorouracil on cell proliferation, cell-cycle progression, apoptosis and regulation of p53, p21, type I collagen (Col-1), vascular endothelial growth factor (VEGF), transforming growth factor-beta1 (TGF-beta1) and matrix metalloproteinase-2 (MMP-2) production in primary cultured keloid fibroblasts were examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), flow cytometric and Western blotting assays. Triamcinolone suppressed cell proliferation and induced G1 cell-cycle arrest but not apoptosis. By contrast, 5-fluorouracil induced G2 cell-cycle arrest and apoptosis that may be associated with p53 activation and p21 up-regulation. The modulation of Col-1, VEGF, TGF-beta1 and MMP-2 expression by triamcinolone and 5-fluorouracil alone or their combination varied between individual cell lines; the trend is to promote a reduction in Col-1 and TGF-beta1 but up-regulation of MMP-2 expression. 5-Fluorouracil played a predominant role in the combined treatment leading to more significant cell proliferation inhibition, apoptosis, Col-1 suppression and MMP-2 induction (p<0.05). Our data provide the molecular-based evidence for the observed clinical benefits of adding 5-fluorouracil to a steroid injection for improved scar regression and reduced recurrence of keloids. We expect fewer undesirable side effects in the combined treatment when the lower therapeutic dose of the individual drugs is to be used.

Retrospective feasibility study of simultaneous integrated boost in cervical cancer using tomotherapy: the impact of organ motion and tumor regression

BackgroundWhole pelvis intensity modulated radiotherapy (IMRT) is increasingly being used to treat cervical cancer aiming to reduce side effects. Encouraged by this, some groups have proposed the use of simultaneous integrated boost (SIB) to target the tumor, either to get a higher tumoricidal effect or to replace brachytherapy. Nevertheless, physiological organ movement and rapid tumor regression throughout treatment might substantially reduce any benefit of this approach.PurposeTo evaluate the clinical target volume - simultaneous integrated boost (CTV-SIB) regression and motion during chemo-radiotherapy (CRT) for cervical cancer, and to monitor treatment progress dosimetrically and volumetrically to ensure treatment goals are met.Methods and materialsTen patients treated with standard doses of CRT and brachytherapy were retrospectively re-planned using a helical Tomotherapy - SIB technique for the hypothetical scenario of this feasibility study. Target and organs at risk (OAR) were contoured on deformable fused planning-computed tomography and megavoltage computed tomography images. The CTV-SIB volume regression was determined. The center of mass (CM) was used to evaluate the degree of motion. The Dice’s similarity coefficient (DSC) was used to assess the spatial overlap of CTV-SIBs between scans. A cumulative dose-volume histogram modeled estimated delivered doses.ResultsThe CTV-SIB relative reduction was between 31 and 70%. The mean maximum CM change was 12.5, 9, and 3 mm in the superior-inferior, antero-posterior, and right-left dimensions, respectively. The CTV-SIB-DSC approached 1 in the first week of treatment, indicating almost perfect overlap. CTV-SIB-DSC regressed linearly during therapy, and by the end of treatment was 0.5, indicating 50% discordance. Two patients received less than 95% of the prescribed dose. Much higher doses to the OAR were observed. A multiple regression analysis showed a significant interaction between CTV-SIB reduction and OAR dose increase.ConclusionsThe CTV-SIB had important regression and motion during CRT, receiving lower therapeutic doses than expected. The OAR had unpredictable shifts and received higher doses. The use of SIB without frequent adaptation of the treatment plan exposes cervical cancer patients to an unpredictable risk of under-dosing the target and/or overdosing adjacent critical structures. In that scenario, brachytherapy continues to be the gold standard approach.

FORENSIC CASES IN THE NORTH OF CHILE: DETERMINATION OF ANTIDEPRESSANT DRUGS IN HUMAN WHOLE BLOOD

The consumption of antidepressant drugs has increased in these last years, leading to severe and lethal poisonings. In this work, analytical tools, namely GC/MSD and GC/NPD µECD, were used to identify and quantify several antidepressant drugs including amitriptyline, imipramine, sertraline, fluoxetine, and citalopram in forensic cases in the North of Chile during 2008-2011. Drugs were analyzed in biological arrays like blood. A solid phase extraction by Bond Elut Certify columns was applied in all these processes. Fluoxetine and sertraline were derivatized with pentafluoropropionic anhydride. Prazepam was used as internal standard (IS). The limit of detection (LOD) in blood were 0.5 - 20.07 ng/mL. The average extraction rate was 89.39% in blood. The relative standard deviation (RSD) was less than 3.6%, while the intra-day accuracy was < 5.5% and the inter-day was < 2.4%, referred to RSD. The procedures we have developed allow the quantification of drugs even at low therapeutic doses, a very important issue taking into account the nature of the analyzed arrays.

Novel t(5;19) Translocation in a Patient with PDGFRB Associated Chronic Leukemia: Implications for Treatment Strategy

Myeloproliferative disorders are variable disorders, based on the genetic abnormality present and the cell line progenitors that are affected. In this case, we discuss a novel gene translocation in the subset of PDGFRB mutations, first seen with prominent hyperbasophilia. This case demonstrates the possibility for lower therapeutic doses of imatinib mesylate than previously reported, in order to control leukocyte counts and reverse the genetic mutation.

The value of acute toxicity testing of pharmaceuticals for estimation of human response

The determination of single high doses of active pharmaceutical ingredients (API) is used mostly to fulfill regulatory demands. Oral LD50 values in animals for over 300 API were compared to the minimal effective therapeutic doses (METD) in humans in order to find a correlation between animal and human data. The highest correlation between human METD and animal LD50 was found for the dog (R=0.323), the lowest for the rat (0.287). It was determined that acute oral LD50 of rats have poor correlation with the METD, and cannot be used as a classification criteria into official acute toxic categories. Only 13% of API has been classified as fatal if swallowed according to the EU CLP regulation, none of the substances with very low therapeutic dose have been identified as EU CLP acute toxicity category 1. Substances with very low therapeutic doses, which could potentially have toxic effects in humans, are not identified with the use of oral LD50 and current classification system. We propose that the acute toxicity based on rat LD50 dose is not used as a basis for classification of pharmaceuticals, and that the METD is applied as basis for classification.

Validation of Warfarin Pharmacogenetic Algorithms in Clinical Practice

The goal of this study was to evaluate the performance of four warfarin pharmacogenetic algorithms in a real clinical setting, namely the algorithms of Gage et al., Michaud et al., Wadelius et al. and the International Warfarin Pharmacogenetics Consortium algorithm. Data was obtained retrospectively for 605 patients who had initiated warfarin therapy at the Montreal Heart Institute. Warfarin dosing and International Normalized Ratio history were obtained from hospital charts and CYP2C9 and VKORC1 polymorphisms were genotyped. The four algorithms produced similar accuracy with mean absolute error ranging from 1.36-1.52 mg/day and adjusted R(2) from 40-44%. Gage's algorithm and Wadelius' algorithm predicted the largest proportion of patients within ± 20% of their observed stable warfarin dose. For patients requiring low doses, Gage's algorithm provided the highest proportion of patients within ideal dose range (36.3%), while Wadelius' algorithm performed the best for patients requiring high doses (37.3% of patients within ideal dose range). Our study demonstrates the value of published pharmacogenetic dosing algorithms for the prediction of warfarin doses, in particular for patients with low or high therapeutic dose requirements.

Histological study of the effect of paracetamol on the seminiferous tubules of adult rabbits

Background Paracetamol (acetaminophen) is a frequently used analgesic and antipyretic drug that is widely available without a prescription. Its overdose causes tissue injury, particularly in the liver. Aim of the work This study was conducted to determine the effect of paracetamol on the seminiferous tubules of adult rabbits. Materials and methods In this study, 18 adult male rabbits were utilized and equally divided into three groups (n=6): a control group (group I), a paracetamol low therapeutic dose group (group II), which received daily oral dose (8 mg/kg/day) for 3 weeks, and a paracetamol high therapeutic dose group (group III), which received a daily oral dose (16 mg/kg/day) for 3 weeks. Testicular specimens were obtained 1, 2, and 3 weeks from the start of the experiment and sections were prepared for light microscopic (H&E and Masson’s trichrome) and electron microscopic examination. Statistical analysis for the mean area % of collagen fibers was performed. Results The results revealed that a low dose of paracetamol exerted no harmful effect on the histological structure of seminiferous tubules, whereas a high dose induced a mild harmful effect (few spermatogenic cells with cytoplasmic vacuolization and small dark nuclei) after 1 week that became moderate in the second week sections. The effect of paracetamol was severe in the third week sections, with cell loss and alteration of the basement membrane of some spermatogenic cells. Statistical analysis of collagen fibers revealed a significant increase in collagen fibers’ accumulation in the second and third week sections of the high-dose paracetamol group. Conclusion It could be concluded that paracetamol is toxic to the rabbit testis when it is used in high repeated therapeutic doses. Thus, it should be used with caution, especially when a large, prolonged dose is indicated.

Abstract 16907: Modification of Hemeoxygenase-1 Expression Enhances the Therapeutic Potency of CD34+ Cells in Ischemic Tissue Repair

The potency of cell-based therapy in ischemic tissue repair is limited by low viability and retention of transplanted cells. The hemeoxygenase system catabolizes heme cleavage and has been shown to exert cytoprotection via its anti-oxidative, -apoptotic, -inflammatory properties. HO-1, inducible in various pathologic states, has been shown to influence progenitor cell biology. We hypothesized that HO-1 over-expression enhances the therapeutic potency of CD34+ cells for ischemic tissue repair. CD34+ from healthy donors were enriched from the peripheral blood mononuclear cell fraction of healthy donors after G-CSF mobilization (Isolex 300i). Adenoviral transduction of HO-1/GFP or GFP led to a substantial increase of HO-1 expression (HO-1/18s RNA expression: 62-fold increase, protein expression: 20-fold increase; n=3). After allowing 48 hrs for target gene expression, CD34+ cells were FACS-sorted for GFP followed by overnight recovery in-vitro. A low-therapeutic dose (10^5 cells/kg) of HO-1+/GFP+ (HO-1) or GFP+ (GFP) CD34+ cells was locally injected into the border zone after complete ligation of the left coronary artery in 8-week-old, male nude mice (saline control: 2x 15 μl). At day 28, LV ejection fraction of mice treated with HO-1 over-expressing CD34+ cells was significantly improved (fractional shortening: saline 19±2%, HO-1 30±1%, GFP 24±1%; n=6-8/group, P&lt;0.01). This functional improvement can be explained by a preservation of the border-zone: the number of lectin+ capillaries was increased (lectin staining: saline 73±5/hpf, HO-1 99±4/hpf, GFP 79±7/hpf; n=7-8/group, P&lt;0.01) with the use of HO-1 modified CD34+ cells while lectin+/alpha-smooth-muscle actin+ structures indicative for resistance vessels remained unchanged (P=ns). Apoptosis of resident myocardial cells was attenuated (TUNEL staining: saline 69±5/hpf, HO-1 31±3, GFP 54±9, P&lt;0.05). As a result, the infarct size in mice treated with HO-1 modified cells was reduced (Masson-trichrome staining: saline 39±1%, HO-1 36±2%, GFP 42±1%; n=6-8/group, P&lt;0.05). Ongoing studies are addressing the underlying mechanism(s) on cellular basis as well as the clinical relevance. Conclusion: HO-1 gene modification enhances the therapeutic potency of CD34+ in ischemic tissue repair.

Fast dissolving β-lapachone particles and tablets: an approach using surface adsorption technique

Background: β-lapachone (βLAP) is obtained from natural resources with promising preliminary results against the etiologic agent of Chagas disease. βLAP activity is associated with generation of free radical and inhibition of nucleic acids and protein synthesis leading an outstanding antichagasic action. Low water solubility and large therapeutic doses constitute the main problems to overcome in the development of dosage forms of this drug.Objective: The purpose of the present research was to enhance the limited dissolution rate of βLAP by promoting the spontaneous crystalline growth of βLAP on the surface of an inert excipient.Methods: Physicochemical characterization of the particles was carried out as well as the drug dissolution rate. Drug adsorbed particles were compared to the drug as supplied and its physical mixtures with the inner excipient. The utility of the βLAP adsorbed particles in the development of tablets obtained by direct compression were also evaluated.Results: Particles produced by spontaneous crystalline growth of βLAP on microcrystalline cellulose (MCC) hydrophilic surface showed mean diameters between 55–65 µm and fast drug dissolution rate (90% drug dissolved at 50 min). Neither physical nor chemical instability of the drug were detected after the drug adsorption procedure. The compression process does not extensively deteriorate the dissolution behaviour of the systems when an adequate compression pressure is used.Conclusions: Surface adsorption technique offers a simple way to produce βLAP powder and tablets with improved dissolution rate for oral administration.

Linagliptin: A Novel Xanthine-Based Dipeptidyl Peptidase-4 Inhibitor for Treatment of Type II Diabetes Mellitus

Type 2 diabetes mellitus causes significant morbidity and mortality on account of its progressive nature and results in considerable burden on healthcare resources. Current treatment strategies have only limited long-term efficacy and tolerability given the progressive nature of the disease leading to inadequate glycemic control and are also associated with undesirable side effects such as weight gain, hypoglycemia and gastrointestinal distress. In the light of these existing limitations, exploring new treatment targets and new therapies have become the need of the hour at present. The incretin pathway, in particular, glucagon-like peptide (GLP-1), plays an important pathological role in the development of type 2 diabetes mellitus, and treatments targeting the incretin system have recently generated surmount interest. These can mainly be categorized into two broad classes; GLP-1 agonists/analogs (exenatide, liraglutide), and dipeptidyl peptidase- 4 inhibitors (sitagliptin, vildagliptin). The gliptins act by prolonging the action of incretins, the gut hormones which can boost insulin levels. Linagliptin is the latest dipeptidyl peptidase-4 inhibitor to complete pivotal phase III trials, which have demonstrated its superiority to its competitors based on its low therapeutic dose, long-lasting inhibition of DPP-4 activity and a good safety/tolerability profile. One of the unique characteristics of linagliptin is its primarily non-renal route of excretion. The drug has recently been approved by the US Food and Drug Administration and has been portrayed as a promising treatment option for patients in whom metformin and the other DPP-4 inhibitors are either contraindicated or require dose adjustment because of moderate to severe renal impairment.

A Randomized Double-Blind, Placebo-Controlled Multicenter Study to Evaluate the Efficacy and Safety of Two Doses of the Tramadol Orally Disintegrating Tablet for the Treatment of Premature Ejaculation Within Less Than 2 Minutes

BackgroundPremature ejaculation (PE) is a widely observed male sexual dysfunction with a major impact on quality of life for many men and their sexual partners. ObjectiveTo assess the safety of tramadol orally disintegrating tablet (ODT) (Zertane) and its efficacy in prolonging intravaginal ejaculation latency time (IELT) and improving Premature Ejaculation Profile (PEP) scores. Design, setting, and participantsWe conducted an integrated analysis of two identical 12-wk randomized double-blind, placebo-controlled phase 3 trials across 62 sites in Europe. Healthy men 18–65 yr of age with a history of lifelong PE according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision, and an IELT ≤120s were included. There were 604 intent-to-treat subjects included in the analysis. InterventionSubjects were randomized to receive 1:1:1 placebo (n=200), 62mg tramadol ODT (n=206), or 89mg tramadol ODT (n=198). MeasurementsWe measured overall change and fold increase in median IELT and the mean change in all four measures of the PEP. Differences across treatment groups were analyzed using Wilcoxon rank-sum tests, analysis of variance, and chi-square analyses. Results and limitationsTramadol ODT resulted in significant increases in median IELT compared with placebo; increases were 0.6min (1.6 fold), 1.2min (2.4 fold), and 1.5min (2.5 fold) for placebo, 62mg tramadol ODT, and 89mg tramadol ODT, respectively (p<0.001 for all comparisons). Men saw significantly greater improvement in all four measures of the PEP in both doses compared with placebo (p<0.05 for all comparisons). Tramadol ODT was well tolerated; study discontinuation occurred in 0%, 1.0%, and 1.6% of subjects in placebo, 62mg, and 89mg tramadol ODT groups, respectively. Limitations include study inclusion for men with IELT up to 120s. ConclusionsOn-demand 62mg tramadol ODT is an effective treatment for PE in a low and safe therapeutic dose and provides a new option for managing mild to severe PE. Trial registrationClinicalTrials.gov identifiers NCT00983151 and NCT00983736; http://clinicaltrials.gov/.