Integrated twin-screw wet granulation, continuous vibrational fluid drying and milling: A fully continuous powder to granule line.

Highly homogeneous low-dose (50 µg) tablets were produced incorporating perfectly free-flowing granules prepared by a fully integrated Continuous Manufacturing (CM) line. The adopted CM equipment consisted of a Twin-Screw Wet Granulator (TSWG), a Continuous Fluid Bed Dryer (CFBD) and a Continuous Sieving (CS) unit. Throughout the experiments a pre-blend of lactose-monohydrate and corn starch was gravimetrically dosed with 1 kg/h into the TSWG, where they were successfully granulated with the drug containing water-based PVPK30 solution. The wet mass was subsequently dried in the CFBD on a vibratory conveyor belt and finally sieved in the milling unit. Granule production efficiency was maximized by determining the minimal Liquid-to-Solid (L/S) ratio (0.11). Design of Experiments (DoE) were carried out in order to evaluate the influence of the drying process parameters of the CFBD on the Loss-on-Drying (LOD) results. The manufactured granules were compressed into tablets by an industrial tablet rotary press with excellent API homogeneity (RSD < 3%). Significant scale-up was realized with the CM line by increasing the throughput rate to 10 kg/h. The manufactured granules yielded very similar results to the previous small-scale granulation runs. API homogeneity was demonstrated (RSD < 2%) with Blend Uniformity Analysis (BUA). The efficiency of TSWG granulation was compared to High-Shear Granulation (HSG) with the same L/S ratio. The final results have demonstrated that both the liquid distribution and more importantly API homogeneity was better in case of the TSWG granulation (RSD 1.3% vs. 4.5%).

Application of hydroxypropyl methylcellulose as a protective agent against magnesium stearate induced crystallization of amorphous itraconazole.

Itraconazole is a fungicide drug which has low bioavailability due to its poor water solubility. Amorphous solid dispersion (ASD) is a tool that has the potential to greatly increase the dissolution rate and extent of compounds. In this work, the dissolution of tablets containing the ASD of itraconazole with either hydroxypropyl methylcellulose (HPMC) or vinylpyrrolidone-vinyl acetate copolymer (PVPVA) was compared in order to find a formulation which can prevent the drug from the precipitation caused by magnesium stearate. Formulations containing the PVPVA-based ASD with HPMC included in various forms could reach 90% dissolution in 2 h, while HPMC-based ASDs could release 100% of the drug. However, HPMC-based ASD had remarkably poor grindability and low bulk density, which limited its processability and applicability. The latter issue could be resolved by roller compacting the ASD, which significantly increases the bulk density and the flowability of the powder blends used for tableting. This roller compaction step might be a base for the industrial application of HPMC-based, electrospun ASDs.

Investigation of Deteriorated Dissolution of Amorphous Itraconazole: Description of Incompatibility with Magnesium Stearate and Possible Solutions.

Disadvantageous crystallization phenomenon of amorphous itraconazole (ITR) occurring in the course of dissolution process was investigated in this work. A perfectly amorphous form (solid dispersion) of the drug was generated by the electroblowing method (with vinylpyrrolidone-vinyl acetate copolymer), and the obtained fibers were formulated into tablets. Incomplete dissolution of the tablets was noticed under the circumstances of the standard dissolution test, after which a precipitated material could be filtered. The filtrate consisted of ITR and stearic acid since no magnesium content was detectable in it. In parallel with dissolution, ITR forms an insoluble associate, stabilized by hydrogen bonding, with stearic acid deriving from magnesium stearate. This is why dissolution curves do not have the plateaus at 100%. Two ways are viable to tackle this issue: change the lubricant (with sodium stearyl fumarate >95% dissolution can be accomplished) or alter the polymer in the solid dispersion to a type being able to form hydrogen bonds with ITR (e.g., hydroxypropyl methylcellulose). This work draws attention to one possible phenomenon that can lead to a deterioration of originally good dissolution of an amorphous solid dispersion.

Detailed stability investigation of amorphous solid dispersions prepared by single-needle and high speed electrospinning.

In this research the long-term stability (one year) of amorphous solid dispersions (ASDs) prepared by high speed electrospinning was investigated at 25 °C/60% relative humidity (RH) (closed conditions) and 40 °C/75% RH (open conditions). Single needle electrospinning and film casting were applied as reference technologies. Itraconazole (ITR) was used as the model API in 40% concentration and the ASDs consisted of either one of the following polymers as a comparison: polyvinylpyrrolidone-vinyl acetate 6:4 copolymer (no hydrogen bonds between API and polymer) and hydroxypropyl methylcellulose (possible hydrogen bonds between oxo or tertiary nitrogen function of API and hydroxyl moiety of polymer). DSC, XRPD and dissolution characteristics of samples at 0, 3 and 12 months were investigated. In addition, Raman maps of certain electrospun ASDs were assessed to investigate crystallinity. A new chemometric method, based on Multivariate Curve Resolution-Alternating Least Squares algorithm, was developed to calculate the spectrum of amorphous ITR in the matrices and to determine the crystalline/amorphous ratio of aged samples. As it was expected ITR in single needle electrospun SDs was totally amorphous at the beginning, in addition hydroxypropyl methylcellulose could keep ITR in this form at 40 °C/75% RH up to one year due to the hydrogen bonds and high glass transition temperature of the SD. In polyvinylpyrrolidone-vinyl acetate matrix ITR remained amorphous at 25 °C/60% RH throughout one year. Materials prepared by scaled-up, high throughput version of electrospinning, which is compatible with pharmaceutical industry, also gained the same quality. Therefore these ASDs are industrially applicable and with an appropriate downstream process it would be possible to bring them to the market.

Downstream processing of polymer-based amorphous solid dispersions to generate tablet formulations.

Application of amorphous solid dispersions (ASDs) is considered one of the most promising approaches to increase the dissolution rate and extent of bioavailability of poorly water soluble drugs. Such intervention is often required for new drug candidates in that enablement, bioavailability is not sufficient to generate a useful product. Importantly, tableting of ASDs is often complicated by a number of pharmaceutical and technological challenges including poor flowability and compressibility of the powders, compression-induced phase changes or phase separation and slow disintegration due to the formation of a gelling polymer network (GPN). The design principles of an ASD-based system include its ability to generate supersaturated systems of the drug of interest during dissolution. These metastable solutions can be prone to precipitation and crystallization reducing the biopharmaceutical performance of the dosage form. The main aim of the research in this area is to maintain the supersaturated state and optimally enhance bioavailability, meaning that crystallization should be delayed or inhibited during dissolution, as well as in solid phase (e.g., during manufacturing and storage). Based on the expanding use of ASD technology as well as their downstream processing, there is an acute need to summarize the results achieved to this point to better understand progress and future risks. The aim of this review is to focus on the conversion of ASDs into tablets highlighting results from various viewpoints.

H2S preconditioning of human adipose tissue-derived stem cells increases their efficacy in an in vitro model of cell therapy for simulated ischemia.

AIMS: A major limitation of cell-based therapies for ischemia-reperfusion injury is the excessive loss of administered cells. We investigated whether H2S can improve the survival and efficacy of therapeutic cells in an in vitro model of cell-based therapy for simulated ischemia. MAIN METHODS: H9c2 rat cardiomyoblasts were exposed to oxygen-glucose deprivation and NaHS (3-30 µM) pretreated human adipose tissue derived stem cells (hASCs) were added after reoxygenization. Viability of both cell lines was assessed with flow cytometry after 24h. The effects of H2S on antioxidant defense, proliferation, AKT and ERK1/2 phosphorylation and mitochondrial activity were analyzed in hASCs. Proliferation was evaluated using propargylglycine, an inhibitor of endogenous H2S synthesis. KEY FINDINGS: NaHS pretreatment decreased the ratio of necrotic therapeutic cells by 41.8% in case of 3 µM NaHS and by 34.3% with 30 µM NaHS. The ratio of necrotic postischemic cardiomyocytes decreased by 35%, but only with the use of 3 µM NaHS. Antioxidant defense mechanisms and ERK-phosphorylation were enhanced after 3 µM NaHS treatment while AKT-phosphorylation was suppressed. NaHS dose-dependently increased the proliferation of hASCs while pretreatment with propargylglycine decreased it. SIGNIFICANCE: NaHS pretreatment can increase the survival of therapeutically used human adipose tissue-derived stem cells via increased antioxidant defense and improves the postischemic cardiac derived cells' survival as well. Proliferation of human adipose tissue-derived stem cells is enhanced by H2S. The underlying mechanisms involve enhanced ERK-phosphorylation and decreased AKT-phosphorylation. Pretreatment with NaHS may represent a simple pharmacological step that may enhance the efficacy of cell-based therapies.

FT-IR spectral, DFT studies and detailed vibrational assignment on N,N',N"-tris(2-aminoethyl)-phosphoric acid triamide.

Structure of N,N',N"-tris(2-aminoethyl)-phosphoric acid triamide (TEDAP), which is a phosphorus-containing reactive amine crosslinking agent and flame retardant material as well, identified by Fourier transform infrared (FT-IR) spectroscopy and quantum chemical calculations. The FT-IR spectrum of TEDAP, being a recently synthesized new compound, has been recorded in the 4000-650 cm(-1) region for the first time. The molecular geometry and vibrational wavenumbers of the compound in its ground state have been calculated by using Density Functional Theory (DFT) using B3LYP functional with 6-311++G(d,p) basis set. All calculations were performed with Gaussian09 software. The obtained vibrational wavenumbers and optimized geometric parameters were seen to be in good agreement with the experimental data. Furthermore, assignments of each vibrational mode were interpreted in terms of potential energy distributions (PED) in detail.

[Impending paradoxical embolism]. / Fenyegetó paradox embolia esete.

The case history of a 49-year-old female patient is reported, who was operated on because of varicose vein in the left lower extremity. A few days after the operation serious signs of cerebrovascular insult appeared. The clinical picture and the result of an urgent transoesophageal echocardiography are described; a serpentine thrombus was found to be trapped in the patent foramen ovale. During continuous intravenous heparin treatment, the patient gradually recovered, but a residual neurological deficit could be detected on discharge from the hospital. Six days after the admission, repeated transoesophageal echocardiographic examination showed no signs of intracardiac thrombus. The clinical feature of the illness, the predisposing factors, the diagnostic and therapeutic possibilities are discussed.

[ECG repolarization disorder (QT lengthening) in organophosphate poisoning]. / EKG repolarisatios zavar (QT megnyúlás) vizsgálata szerves foszforsavészter mérgezésben.

The authors investigated in human and in experimental organophosphate intoxication the features of the toxic ECG repolarisation disturbance, the QT lengthening and its connection with cholinesterase depression. It was concluded that this pathological electrophysiological change in human intoxication does not show close correlation with the decrease of enzyme activity and cannot be influenced by atropine. The ECG alteration can be reproduced in animal experiments, it precedes the toxicologically relevant cholinesterase depression, it is pesticide dose dependent, but it cannot be induced by cholinergic or adrenergic drugs. On the basis of all this it is supposed that in organophosphate intoxication the QT lengthening reflects a direct myocardial pesticide effect and, is independent of cholinergic mediation.

Detection and localization of ventricular preexcitation in Wolff-Parkinson-White syndrome (comparative study with body surface mapping).

21 patients with Wolff-Parkinson-White (WPW) syndrome were investigated through radionuclide imaging and body surface mapping. Ventricular preexcitation was localized by display of identical phase ventricular regions (phase display). In 79% of the cases radioisotope and body surface mapping methods have identical results for the site of preexcitation. In two patients of the control group (10 patients with Lown-Ganong-Levine (LGL) syndrome), false positive outside-of septum ventricular preexcitation was detected, i.e. an 80% specificity. It is concluded that phase display might be a suitable method in the diagnosis of WPW syndrome. The sensitivity of this method can be improved using several views.

Dimethoate-induced toxic cardiac failure in the guinea pig.

In anaesthetized guinea-pigs treated with lethal doses of dimethoate, cardiac failure and serious ECG disturbances developed in the early phase of intoxication. The toxic cardiac phenomena appeared to be unrelated to the degree of cholinesterase inhibition, but showed a close correlation with myocardial dimethoate concentration. Cardiac failure and mortality were first observed at a critical pesticide level of about 110 micrograms/g, while a level of 221 micrograms/g resulted in death in all cases. The present investigation refers to the direct effect of the pesticide on the myocardium, independent of its anticholinesterase action.

Clinical experiences with pipecuronium bromide.

In two groups of patients the neuromuscular and circulatory effects of pipecuronium bromide (Arduan R), a new steroid type muscle relaxant were compared with those of pancuronium during balanced anaesthesia. Pipecuronium (n = 18) was found to be about 20% more potent than pancuronium (n = 20). The 95% blocking doses were: 0.059 mg kg-1 for pipecuronium and 0.075 mg kg-1 for pancuronium; these doses provided equal intubating conditions and relaxation. The onset, clinical relaxation time (clinical duration), recovery and the reversibility of the neuromuscular effects of the two agents in equipotent doses were similar. No cardiovascular or other side effects were observed with the use of pipecuronium.