Comparative, Single-Dose, 2-Way Cross-Over Bioavailability Study of Two Olanzapine 10 Mg Tablet Formulations in Healthy Volunteers Under Fasting Conditions.

Objectives: Olanzapine is an atypical antipsychotic that is approved across Europe, the USA, and in many other countries for oral treatment of schizophrenia and acute manic episodes in patients with bipolar disorder as well as for maintenance therapy to prevent recurrence in responders. The objective of the present study was to compare the pharmacokinetics of two 10 mg tablet formulations of Olanzapine following a single oral dose in healthy volunteers under fasting conditions, as per the European Medicine Agency (EMA) guidelines to grant marketing authorization. Methods: This study was a randomized, open-label, two-treatment, two-period, two-sequences, single-dose, cross-over design with a washout period of 14 days. Both the test and the reference products were administered as 10 mg tablets with 240 mL of water after an overnight fast in each study period. A total of twenty blood samples were collected before dosing and within 144 hours after drug administration. Adverse events were monitored, recorded, and evaluated by investigators throughout the study. Results: Of the 24 healthy adult male subjects enrolled, all of them completed both study periods. The geometric mean ratio 90% confidence intervals (CI) for fasting Cmax, AUC0-t, and AUC0-infinity were 94.83-113.71%, 95.04-105.69% and 95.94-107.00%, respectively. The 90% CI for the ratios of the three primary pharmacokinetic parameters (using log-transformed data) were within the range of 80-125%, meeting the regulatory criteria for bioequivalence. Conclusions: The generic Olanzapine was bioequivalent to the reference formulation. It was well tolerated and provides an acceptable alternative to the reference drug.

Transmission Electron Microscopy: Novel Application of Established Technique in Characterization of Nanoparticles as Drug Delivery Systems.

Nanotechnology presents a modern field of science that in the last twenty-five years plays a dominant role in the biomedicine. Different analytical methods are used for evaluation of the physico-chemical properties of nanoparticles including chromatography, electrophoresis, X-ray scattering, spectroscopy, mass spectrometry, zeta potential measurement and microscopy on which this article will focus. Herein, we present novel application of the long-established TEM technique that is focused on characterization and evaluation of various nanoparticles in development of drug delivery systems. Transmission electron microscopy images were taken of samples from native nanoparticles, nanoparticles labeled using stannous chloride labeling procedure, inorganic silica nanoparticles loaded with budesonide and native micelles and micelles carrier of anticancer drug camptothecin. In the case of radiolabeled nanoparticles, beside for nanoparticle characterization, TEM technique was used to confirm the stability of the nanoparticles after radiolabeling. Furthermore, the porous structure of hybrid silica particles loaded with budesonide was examined under TEM. Transmission electron microscopy technique offers exceptional benefits for nanoparticle characterization. Additionally, the necessity of ultrastructural analysis demonstrates the potential of TEM in the field of nanomedicine. Hence, the long-established and well-known TEM has been only partially exploited and offer researchers very detailed images of specimens at microscopic and nano scale.

A New Solid-Phase Extraction Method for Determination of Pantoprazole in Human Plasma Using High-Performance Liquid Chromatography.

BACKGROUND: A new simple, selective and accurate high-performance liquid chromatographic (HPLC) method utilising solid-phase extraction for the determination of pantoprazole in human plasma samples has been developed. AIM: The purpose of this paper was developing a new HPLC method suitable for the determination of pantoprazole in plasma samples, which enables simple and rapid isolation and concentration of the analysed drug. METHODS: The chromatographic separation was accomplished on a LiChroCart LiChrospher 60 RP select B column using a mobile phase composed of 0.2 % (V/V) water solution of triethylamine (pH 7) and acetonitrile (58:42, V/V) followed by UV detection was at 280 nm. The solid-phase extraction method using LiChrolut RP-18 (200 mg, 3 ml) was applied to the obtained good separation of investigated drug from endogenous plasma components. Best results were achieved when plasma samples were buffered with 0.1 mol/L KH2PO4 (pH 9) before extraction, eluted and reconstituted with acetonitrile and 0.001 mol/L NaOH after extraction, respectively. RESULTS: The standard calibration curves showed good linearity within the range of 25.0-4000.0 ng/mL with a correlation coefficient greater than 0.996. Retention times of pantoprazole and internal standard, lansoprazole was 4.1 and 6.0 min respectively. The limit of quantification was 25.0 ng/mL. For intra- and inter-day precision relative standard deviations ranged from 4.2 to 9.3%. The relative errors for stability investigations were ranged from 0.12 to -10.5%. CONCLUSION: This method has good precision and accuracy and was successfully applied to the pharmacokinetic and bioequivalence study of 40 mg pantoprazole in healthy volunteers.

Importance of 6-Thioguanine Nucleotide Metabolite Monitoring in Inflammatory Bowel Disease Patients Treated with Azathioprine.

The active metabolite of azathioprine, 6-thioguanine nucleotide (6-TGN) is the main component responsible for the immunosuppressive effect in treatment of inflammatory bowel disease (IBD). The aim of this study was to assess the correlation between the concentration of 6-thioguanine nucleotide and disease activity, azathioprine-related adverse effects and time duration of treatment in patients with inflammatory bowel disease. Thirty-four patients were included in this study. Type of disease, gender, time duration of therapy and adverse effects were recorded. Metabolite concentration was determined by high performance liquid chromatography. Twenty-one percent of patients have experienced an adverse effect, with leucocytopenia most commonly occurring (42.9%). More adverse effects were registered when patients were treated with azathioprine in a period of less than 3 months in comparison to the group of patients that have been under therapy between 3-12 months and more than 12 months (p˂0.05). Most of the patients that presented any adverse effect had high 6-TGN concentration (>450 pmol/8x108 Er). The mean value of 6-TGN metabolite concentration in IBD patients treated with azathioprine was 437.46 pmol/8x108 Er ± 198.82 pmol/8x108. The time duration of azathioprine treatment did not have any significant impact on the achieved 6-TGN concentration (p>0.05).Twenty patients (58.9%) had achieved remission after therapy initiation with azathioprine. More alertness is recommended to clinicians towards patients in the first 3 months of the therapy. Our study demonstrated that higher 6-TGN concentration is associated with azathioprine toxicity.

High Performance Liquid Chromatographic Method for Direct Determination of Diazepam in Whole Blood and Serum - Optimization of Solid-Phase Extraction Method.

Herein, we present a simple and rapid high performance liquid chromatographic (HPLC) method with UV-detection for the direct determination of diazepam in whole blood and serum that can be used for monitoring diazepam levels in clinical samples analysis. The isolation of diazepam and the internal standard bromazepam from serum and whole blood samples was performed using solid phase extraction method with RP select B cartridges. The analytes were separated employing a reversed phase C8 column with a mobile phase composed of 0.1 % (V/V) triethylamine in water (pH 3.5) and acetonitrile (63:37, V/V). UV detection was carried out at 240 nm. Linearity was achieved in the range from 10.0-1000.0 ng/ml for serum and whole blood. The method was applied to spiked and real biological samples after an oral administration of 10 mg diazepam. In conclusion, the proposed method is simple, rapid and provides efficient clean-up of the complex biological matrix and high recovery of diazepam.

Six week follow-up of metabolic effects induced by a high-fat diet and streptozotocin in a rodent model of type 2 diabetes mellitus.

This study was initiated to refine and characterize a nongenetic experimental model of type 2 diabetes mellitus and to follow up various metabolic parameters up to six weeks after diabetes induction. Male Wistar rats were divided into 4 groups: CON group--consumed standard rat chow and served as control; HFD group--consumed high-fat diet (45% calories as fat); STZ group-was injected once intraperitoneally with streptozotocin (35 mg/kg) on day 14, and DM-2 group--consumed high-fat diet and was injected with streptozotocin. The metabolic parameters were measured one week after streptozotocin injection (week 3) and at the end of the study (week 9). Our results confirm that HFD-group developed dyslipidaemia, obesity and insulin resistance. All metabolic parameters remained largely unaltered in STZ-group during the study. Only the combination of high-fat diet and streptozotocin (DM-2 group) induced type 2 diabetes that was characterized with moderate hyperglycaemia, insulin resistance, hypertriglyceridaemia, elevated free fatty acids, hypercholesterolaemia and increased plasma glucagon levels at the time of diabetes onset (week 3). The observed changes of the metabolic parameters after six additional weeks demonstrated an aggravated diabetic state, as confirmed from significantly increased fasting plasma glucose values, insufficient insulin secretion, severe hyperlipidaemia, increased glucagon levels, decreased serum adiponectin concentrations and significantly elevated urinary protein excretion. These results indicate that apart from its utility as a model of diabetes aetiology, this model could also be used for elucidating the role of the hormones adiponectin and glucagon in the progression of type 2 diabetes, as well as for investigating the diabetic complications.