Physico‐chemical stability of docetaxel premix solution and docetaxel infusion solutions in PVC bags and polyolefine containers

We assessed the physical and chemical stability of docetaxel infusion solutions. Stability of the antineoplastic drug was determined 1.) after reconstitution of the injection concentrate and 2.) after further dilution in two commonly used vehiclesolutions, 0.9% sodium chloride and 5% dextrose, in PVC bags and polyolefine containers. Chemical stability was measured by using a stabilityindicating HPLC assay with ultraviolet detection. Physical stability was determined by visual inspection. The stability tests revealed that reconstituted docetaxel solutions (= premix solutions) are physicochemically stable (at a level 95% docetaxel) for a minimum of four weeks, independent of the storage temperature (refrigerated, room temperature). Diluted infusion solutions (docetaxel concentration 0.3 mg/ml and 0.9 mg/ml), with either vehiclesolution, proved physicochemically stable (at a level 95% docetaxel) for a minimum of four weeks, when prepared in polyolefine containers and stored at room temperature. However, diluted infusion solutions exhibited limited physical stability in PVC bags, because docetaxel precipitation occured irregularly, though not before day 5 of storage. In addition, timedependent DEHPleaching from PVC infusion bags by docetaxel infusion solutions must be considered.     

Physical stability of albinterferon-α(2b) in aqueous solution: effects of conformational stability and colloidal stability on aggregation

Controlling aggregation in protein therapeutics is a significant challenge. In this study, the aggregation behavior of albinterferon-α(2b) , a genetic fusion protein combining human serum albumin and α-interferon, was examined as a function of solution conditions. The stability was monitored during agitation and during storage at elevated temperature, where the extent of aggregation was determined using size-exclusion chromatography. The osmotic second virial coefficient and the free energy of unfolding were measured for each sample. This study demonstrates that both increasing conformational stability and maximizing colloidal stability help to maintain the physical stability of albinterferon-α(2b).     

Light effect on the stability of β-lapachone in solution: pathways and kinetics of degradation

Objectives The purpose of this work was to study the chemical stability of the new antitumoral β‐lapachone (βLAP) to determine the degradation pathway/s of the molecule and the degradation kinetics in addition to identifying several degradation products. Method Samples of βLAP in solution were stored under conditions of darkness and illumination at 40°C at which the pseudo‐first order rate constants for the βLAP degradation were determined. Furthermore, drug degraded solutions were concentrated and purified using Sephadex LH‐20 and preparative thin‐layer chromatography and degradation products were identified by nuclear magnetic resonance spectroscopy. Key findings The results revealed that βLAP shows two different degradation routes: hydrolysis in the dark and photolysis under the light. The βLAP exposure to light accelerated the drug degradation about 140 fold, compared with the samples stored in the absence of light. The hydrolysis produced hydroxylapachol as the main degradation product. The photolysis yielded phthalic acid, 6‐hydroxy‐3methylene‐3H‐isobenzofuran‐1‐one and a benzomacrolactone together with a complex mixture of other phthalate‐derivatives such as 2‐(2‐carboxy‐acetyl)‐benzoic acid. Conclusions This study provides useful information for the development of βLAP dosage forms, their storage, manipulation and quality control.     

Intravesical delivery of 5‐aminolevulinic acid from water‐in‐oil nano/submicron‐emulsion systems

The present work reports on the development of water‐in‐oil (w/o) emulsions for the intravesical administration of 5‐aminolevulinic acid (ALA). The physicochemical properties of droplet size, zeta potential, and viscosity of the emulsions are characterized and the ability of the emulsions to release ALA following in vitro application is tested. The delivery systems are administered intravesically for 1 and 3 h in rats to examine the drug accumulation in bladder tissue. The mean size and zeta potential of the emulsions are 50–200 nm and ?3 to ?14 mV, respectively. The loading of ALA into the emulsions resulted in a slower and sustained release. The release extent was found to be inversely related to the droplet size of the emulsions. The emulsions did not increase the drug permeation into tissues during short exposure duration (1 h). When the dwell time was extended to 3 h, the systems showed a 2.7‐fold increase in the ALA concentration in the bladder wall. Images of confocal laser scanning microscopy demonstrated a higher and deeper fluorescence signal, with emulsion administration, as compared to the aqueous control. Intravesical emulsion delivery provides a significant advantage for drugs targeting bladder tissues. © 2009 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 2375–2385, 2010     

Stabilization of Octastatin®, a somatostatin analogue: comparative accelerated stability studies of two formulations for freeze-dried products

Octastatin^® (vapreotide INN) is a somatostatin analogue being developed in gastro-enterologic, neuroendocrine and oncologic applications. The pharmaceutical form is a freeze-dried preparation for parenteral injection use. This study was intended to evaluate the stability of the freeze-dried products and to determine the optimally stable formulation. Two types of stabilizing agents (lactose and glutamic acid/sodium glutamate buffer) and three dosage forms (0.5, 1.5, 15 mg of vapreotide base) were investigated. The peptide content and chemical stability of cakes stored at 50 °C and 70% relative humidity were determined by HPLC and the regression analysis parameters calculated. Results indicate that the formulation with glutamate buffer is appropriate for long term storage.     

Phase I trial and pharmacokinetic study of intravenous and oral α-Difluoromethylornithine

Eflornithine-HCl (-difluoromethylornithine or DFMO), an irreversible inhibitor of ornithine decarboxylase, blocks polyamine synthesis and has demonstrated antitumor activity in cell culture and animal tumor models. This phase I study was designed to determine and compare toxicity and the maximally tolerated dose of a 4-day course of DFMO given to patients in oral, continuous intravenous infusion or pulse intravenous infusion forms. Twenty-four patients were entered into this study: 8 received intravenous pulse drug, 10 intravenous continuous infusion of drug, and 6 oral DFMO. The most frequent toxicity was nausea and vomiting which occurred in 9 courses of oral drug. Only two patients receiving intravenous DFMO had nausea and vomiting. Clinically significant thrombocytopenia and audiometric abnormalities were not encountered in contrast to previous experience with 28-day courses of oral DFMO. The maximally tolerated dose of a four-day course of oral DFMO was 3.75 gm/M² every 6 hours. The maximally tolerated dose of intravenous pulse and continuous infusion DFMO was not attained. Pharmacokinetic studies demonstrated that the intravenous schedules achieved higher plasma levels of DFMO than those previously obtained with chronic oral dosing.Presented in part at the 20th Annual Meeting of the American Society of Clinical Oncology, May 1984, Toronto, Ontario, Canada     

Texture Optimization of Water‐in‐Oil Emulsions

The aim of this research is to demonstrate the effect of variations in certain parameters of the oily phase (OP) in water‐in‐oil (W/O) emulsions on rheological and texture properties of finished products. The formulated emulsions were selected according to an optimal experimental procedure. The applied variations were nature of the OP, its volume fraction, the hydrophilic‐lipophilic balance (HLB) value, and the surfactant proportion. Results are presented for the followed tests carried out on the emulsions: texture analysis, rheology, and particle size analysis. The oils used in the study were sweet almond oil, liquid paraffin, maize oil, cyclomethicone, dimethicone, and wheat germ oil. The resulting data demonstrate a notable influence of the volume fraction oil on hardness, viscosity, adhesiveness, and cohesiveness of W/O emulsions. Emulsion hardness and viscosity increased as the OP percentage increased; this effect being even more pronounced for the vegetable oils. In contrast, emulsion adhesiveness and cohesiveness decreased as the volume fraction oil increased. The HLB value of the surfactant mixture of the emulsion also influenced hardness, adhesiveness, and elasticity, increasing or decreasing as HLB value did.     

Regulator of G‐protein signalling 5 protects against atherosclerosis in apolipoprotein E‐deficient mice

Background and Purpose

Atherosclerosis is a chronic inflammatory disease, in which ‘vulnerable plaques’ have been recognized as the underlying risk factor for coronary disease. Regulator of G‐protein signalling (RGS) 5 controls endothelial cell function and inflammation. In this study, we explored the effect of RGS5 on atherosclerosis and the potential underlying mechanisms.

Experimental Approach

RGS5^−/− apolipoprotein E (ApoE)^−/− and ApoE ^−/− littermates were fed a high‐fat diet for 28 weeks. Total aorta surface and lipid accumulation were measured by Oil Red O staining and haematoxylin–eosin staining was used to analyse the morphology of atherosclerotic lesions. Inflammatory cell infiltration and general inflammatory mediators were examined by immunofluorescence staining. Apoptotic endothelial cells and macrophages were assayed with TUNEL. Expression of RGS5and adhesion molecules, and ERK1/2 phosphorylation were evaluated by co‐staining with CD31. Expression of mRNA and protein were determined by quantitative real‐time PCR and Western blotting respectively.

Key Results

Atherosclerotic phenotypes were significantly accelerated in RGS5^−/− ApoE ^−/− mice, as indicated by increased inflammatory mediator expression and apoptosis of endothelial cells and macrophages. RGS5 deficiency enhanced instability of vulnerable plaques by increasing infiltration of macrophages in parallel with the accumulation of lipids, and decreased smooth muscle cell and collagen content. Mechanistically, increased activation of NF‐κB and MAPK/ERK 1/2 could be responsible for the accelerated development of atherosclerosis in RGS5‐deficient mice.

Conclusions and Implications

RGS5 deletion accelerated development of atherosclerosis and decreased the stability of atherosclerotic plaques partly through activating NF‐κB and the MEK‐ERK1/2 signalling pathways.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

ApoE

apolipoprotein E

CHD

coronary heart disease

H&E

haematoxylin‐eosin

ICAM‐1

intercellular adhesion molecue‐1

LDL

low‐density lipoprotein

MEK

MAPK/ERK kinase

RGS

regulator of G‐protein signalling

SMC

smooth muscle cell

VCAM‐1

vascular cell adhesion molecule‐1

Tables of Links

The antinociceptive effects of intravenous tianeptine in colorectal distension-induced visceral pain in rats: the role of 5-HT₃ receptors

Tianeptine is an unusual tricyclic antidepressant drug. In this study, we aimed to investigate the antinociceptive effect of tianeptine on visceral pain in rats and to determine whether possible antinociceptive effect of tianeptine is mediated by serotonergic (5-HT(2,3)) and noradrenergic (α(1,2)) receptor subtypes. Male Sprague Dawley rats (250-300 g) were supplied with a venous catheter, for drug administrations, and enameled nichrome electrodes, for electromyography, at external oblique musculature. Colorectal distension (CRD) was employed as the noxious visceral stimulus and the visceromotor response (VMR) to CRD was quantified electromyographically before and 5, 15, 30, 60, 90 and 120 min after tianeptine administration. Antagonists were administered 10 min before tianeptine for their ability to change tianeptine antinociception. Intravenous administration of tianeptine (2.5-20 mg/kg) produced a dose-dependent reduction in VMR. Administration of 5-HT(3) receptor antagonist ondansetron (0.5, 1 and 2 mg/kg), but not 5-HT(2) receptor antagonist ketanserine (0.5, 1 and 2 mg/kg), reduced the antinociceptive effect of tianeptine (10mg/kg). In addition, administration of α(1)-adrenoceptor antagonist prazosin (1 mg/kg) or α(2)-adrenoceptor antagonist yohimbine (1 mg/kg) did not cause any significant effect on the tianeptine-induced antinociception. Our data indicate that intravenous tianeptine exerts a pronounced antinociception against CRD-induced visceral pain in rats, and suggests that the antinociceptive effect of tianeptine appears to be mediated in part by 5-HT(3) receptors, but does not involve 5-HT(2) receptors or α-adrenoceptors.     

Long‐term stability of morphine and bupivacaine mixture for spinal use

From clinical studies it has been proven that morphine in combination with bupivacaine is applicable in cancer pain. The availability of a ready to use parental dosage form of morphine and bupivacaine is comfortable for health care workers. Stability of a morphine or a bupivacaine preparation or a combination of both in a PVC cassette or polypropylene syringe for spinal use is examined in several studies. Apart from one study no data on longterm stability of morphinebupivacaine mixture is available. A forced degradation study and a shelflife study at room temperature (2025 °C) were started on morphine hydrochloride 0.2 mg/ml and bupivacaine hydrochloride 7.5 mg/ml in 50 ml sterilized glass bottles type II. The results of the stability study showed that this mixture was stable up to 18 months at room temperature, whereafter morphine showed a slight degradation (5 %) and bupivacaine remained stable.     

Dose-effect relationships of intravenous enoxaparin in patients undergoing percutaneous coronary intervention：a population and bayesian approach based study

AIM: Recent studies have suggested that intravenous enoxaparin can be used as an alternative therapy in patients percutaneous coronary intervention (PCI); yet the optimal regimen is to be defined. METHODS: Anti-Xa activities were measured in 556 patients who received a single 0.5 mg/kg dose of enoxaparin intravenously immediately before PCI. A population pharmacoki-     

Who responds to aripiprazole in clinical practice? An observational study of combination versus monotherapy

We aimed to study aripiprazole, as monotherapy and combined with other antipsychotics, in routine clinical practice, to identify patients who had a favourable clinical response. We retrospectively identified all secondary care psychiatric patient records started on aripiprazole (n = 85). We assigned Clinical Global Impression scores to measure effectiveness. We examined demographic and clinical correlates of patients who improved (CGI Improvement scores < 5) versus those who did not improve (CGI >/= 5). 56 patients (66%) received aripiprazole as monotherapy, 29 patients (34%) in combination with other antipsychotics. 52 patients (62%) received a CGI 1-4 (minimally to very much improved), 32 patients (38%) a CGI >/= 5 (no change to very much worse). Patients who improved were less likely to have had previous or subsequent treatment with clozapine (p = 0.04). Discontinuation was due to agitation (35%), inefficacy (21%), nausea (18%) and worsening psychosis (12%). Combination with other antipsychotics resulted in less discontinuation and a lower maximum dose of aripiprazole. Aripiprazole was combined with other regular additional antipsychotics in 1/3rd of patients. Combination and monotherapy were clinically effective in around 60% of patients. Favourable response was associated with lack of treatment resistance. Agitation was the commonest reason for discontinuation.     

Vasodepression to intravenous acetylcholine with attendant vagal blockade — a study of atropine resistance

Summary N,N-di-isopropyl-N-isoamyl-N-diethylaminoethylurea (P-286) and congeners abolished the vasodepressor response to vagal stimulation with little effect on that to intravenous acetylcholine. This effect, although suggestive of parasympathetic ganglionic blockade, was found to be consistent with weak atropine-like activity.Responses to intra-arterial acetylcholine and to vagal stimulation were equally susceptible to blockade by 1-hyoscyamine when measured on specific target organs, as the heart and stomach. The heart, upper gastrointestinal tract and peripheral vasculature were found liable in decreasing order to 1-hyoscyamine blockade.

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Zusammenfassung N,N-Diisopropyl-N-diäthylaminoäthylharnstoff (P-286) und verwandte Verbindungen verhinderten die Blutdrucksenkung bei Vagusreizung, während die Wirkung von i.v. zugeführtem Acetylcholin nur geringfügig abgeschwächt war. Obwohl diese Reaktion eine Blockade parasympathischer Ganglien erwarten läßt, zeigte sich, daß sie auf einer schwachen atropinartigen Wirkung beruht.Gemessen an der Reaktion der Erfolgsorgane Herz und Magen war die Wirkung auf intraarterielle Acetylcholininjektionen und Vagusreizung gleich empfindlich gegenüber 1-Hyoscyamin. Herz, oberer Gastrointestinaltrakt und peripheres Gefäßgebiet reagieren in dieser Reihenfolge weniger deutlich auf die Blockade durch 1-Hyoscyamin.

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With 5 Figures in the Text     

Cerebrolysin lowers kynurenic acid formation — An in vitro study

The therapeutic effect of Cerebrolysin in the treatment of dementia and brain injury has been proposed because of neurotrophic properties of this compound. Since an increased kynurenine metabolism has been documented in several brain pathologies including dementia the aim of the present study was to investigate the biochemical properties of Cerebrolysin with respect to kynurenic acid (KYNA) formation in an in vitro study. KYNA is an endogenous metabolite of the kynurenine pathway of tryptophan degradation and is an antagonist of the glutamate ionotropic excitatory amino acid and of the nicotine cholinergic receptors. The activities of the KYNA synthesizing enzymes kynurenine aminotransferases I, II and III (KAT I, KAT II and KAT III) in rat liver, and rat and human brain homogenates were analysed in the presence of Cerebrolysin. KAT I, II and III activities were measured using a radio-enzymatic method in the presence of 1 mM pyruvate and 100 µM [H³]l-kynurenine. Cerebrolysin, dose-dependently and significantly reduced KAT I, KAT II and KAT III activities of rat liver homogenate. Furthermore, Cerebrolysin exerted a dose-dependent inhibition of rat and human brain KAT I, KAT II and KAT III activities, too. The inhibitory effect of Cerebrolysin was more pronounced for KAT I than for KAT II and KAT III. The present study for the first time demonstrates the ability of Cerebrolysin to lower KYNA formation in rat liver as well as in rat and human brain homogenates. We propose Cerebrolysin as a compound susceptible of therapeutic exploitation in some disorders associated with elevated KYNA metabolism in the brain and/or other tissues. We suggest that the anti-dementia effect of Cerebrolysin observed in Alzheimer patients could be in part due to Cerebrolysin induced reduction of KYNA levels, thus modulating the cholinergic and glutamatergic neurotransmissions.