Novel semi-interpenetrating hydrogel networks with enhanced mechanical properties and thermoresponsive engineered drug delivery,designed as bioactive endotracheal tube biomaterials

Thermoresponsive polymeric platforms are used to optimise drug delivery in pharmaceutical systems and bioactive medical devices. However, the practical application of these systems is compromised by their poor mechanical properties. This study describes the design of thermoresponsive semi-interpenetrating polymer networks (s-IPNs) based on cross-linked p(NIPAA) or p(NIPAA-co-HEMA) hydrogels containing poly(ε-caprolactone) designed to address this issue. Using DSC, the lower critical solution temperature of the co-polymer and p(NIPAA) matrices were circa 34 °C and 32 °C, respectively. PCL was physically dispersed within the hydrogel matrices as confirmed using confocal scanning laser microscopy and DSC and resulted in marked changes in the mechanical properties (ultimate tensile strength, Young’s modulus) without adversely compromising the elongation properties. P(NIPAA) networks containing dispersed PCL exhibited thermoresponsive swelling properties following immersion in buffer (pH 7), with the equilibrium-swelling ratio being greater at 20 °C than 37 °C and greatest for p(NIPAA)/PCL systems at 20 °C. The incorporation of PCL significantly lowered the equilibrium swelling ratio of the various networks but this was not deemed practically significant for s-IPNs based on p(NIPAA). Thermoresponsive release of metronidazole was observed from s-IPN composed of p(NIPAA)/PCL at 37 °C but not from p(NIPAA-co-HEMA)/PCL at this temperature. In all other platforms, drug release at 20 °C was significantly similar to that at 37 °C and was diffusion controlled. This study has uniquely described a strategy by which thermoresponsive drug release may be performed from polymeric platforms with highly elastic properties. It is proposed that these materials may be used clinically as bioactive endotracheal tubes, designed to offer enhanced resistance to ventilator associated pneumonia, a clinical condition associated with the use of endotracheal tubes where stimulus responsive drug release from biomaterials of significant mechanical properties would be advantageous.     

Thermo- and pH-sensitive dendrosomes as bi-phase drug delivery systems

Fully supramolecular dendrosomes (FSD) as bi-phase drug delivery systems are reported in this work. For preparation of FSD, amphiphilic linear-dendritic supramolecular systems (ALDSS) have been synthesized by host-guest interactions between hyperbranched polyglycerol having β-cyclodextrin core and bi-chain polycaprolactone (BPCL) with a fluorescine focal point. Self-assembly of ALDSS in aqueous solutions led to FSD. They were able to encapsulate paclitaxel with a high loading capacity. The dendrosome-based drug delivery systems were highly sensitive to pH and temperature. They were stable at 20–37 °C and pH7–8, but dissociated and released drug at temperatures lower than 20 °C or higher than 37 °C and pH lower than 7 quickly. Dissociation of FSD building blocks by temperature or pH resulted in inclusion complexes between the released drugs and polyglycerol as the secondary drug delivery system.From the Clinical EditorThis paper reports on the development of a pH- (below 7) and temperature- (below 20 °C or above 37 °C) sensitive delivery system using supramolecular dendrosomes for more specific delivery and release of drugs using paclitaxel as a model.     

The chemotherapeutic potential of doxorubicin-loaded PEG-b-PLGA nanopolymersomes in mouse breast cancer model

Vesicles of mPEG-PLGA block copolymer were developed to deliver a therapeutic quantity of doxorubicin (DOX) for breast cancer treatment. The DOX-loaded nanoparticles (NPs) were prepared by the pH-gradient method and then evaluated in terms of morphology, size, DOX encapsulation efficiency and in vitro drug release mechanism.The PEG-PLGA nanopolymersomes were 134 ± 1.2 nm spherical NPs with a narrow size distribution (PDI = 0.121). DOX was entrapped in mPEG-PLGA nanopolymersomes with an encapsulation efficiency and a loading content of 91.25 ± 4.27% and 7.3 ± 0.34%, respectively. The DOX-loaded nanopolymersomes were found to be stable, demonstrating no significant change in particle size and encapsulation efficiency (EE%) during the 6-month storage period of the lyophilized powder at 4 °C. The nanopolymersomes sustained the release of DOX. In cytotoxicity studies of 4T1 cell line samples, free DOX showed a higher cytotoxicity (IC50 = 1.76 μg/mL) than did DOX-loaded nanopolymersomes (15.82 μg/mL) in vitro. In order to evaluate the antitumor efficacy and biodistribution of DOX-loaded nanopolymersomes, murine breast tumors were established on the BALB/c mice, and in vivo studies were performed. The obtained results demonstrated that the prepared drug delivery system was highly effective against a murine breast cancer tumor model and successfully accumulated in the tumor site through an enhanced permeation and retention mechanism.In vivo studies also proved that DOX-loaded nanopolymersomes are stable in blood circulation and could be considered a promising and effective DOX delivery system for breast cancer treatment.     

Novel dual-reverse thermosensitive solid lipid nanoparticle-loaded hydrogel for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect

The purpose of this study was to develop novel solid lipid nanoparticle (SLN)-loaded dual-reverse thermosensitive hydrogel (DRTH) for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect. The flurbiprofen-loaded SLNs were prepared by hot homogenisation technique, after optimising the amounts of lipid mixture (tricaprin and triethanolamine in 8:2 weight ratio), drug and surfactant. The flurbiprofen-loaded thermosensitive SLN composed of drug, lipid mixture and surfactant at a weight ratio of 10/15/1.3 was a solid at room temperature, and changed to liquid form at physiological temperature due to its melting point of about 32 °C. This SLN gave the mean particle size of about 190 nm and entrapment efficiency of around 90%. The DRTHs were prepared by adding this flurbiprofen-loaded thermosensitive SLN in various poloxamer solutions. Their rheological characterisation, release and stability were investigated while a morphological and pharmacokinetic study was performed after its rectal administration to rats compared with the drug and hydrogel. Poloxamer 188 and SLN decreased the gelation temperature and gelation time, but increased the viscosity at 25 °C, gel strength and mucoadhesive force of DRTHs. In particular, the DRTH composed of [SLN/P 407/P 188 (10%/15%/25%)] with the gelation temperature of about 35 °C existed as liquid at room temperature, but gelled at 30–36 °C, leading to opposite reversible property of SLN. Thus, it was easy to administer rectally, and it gelled rapidly inside the body. This DRTH gave a significantly increased dissolution rate of the drug as compared to the flurbiprofen, but significantly retarded as compared to the hydrogel, including the initial dissolution rate. Moreover, this DRTH gave significantly higher plasma concentration and 7.5-fold AUC values compared to the drug, and lower initial plasma concentration and C_max value compared to the hydrogel due to reduced initial burst effect. No damage in rectal mucosa was observed after the application of DRTH. Thus, this DRTH system with improved bioavailability and reduced initial burst effect would be recommended as an alternative for the flurbiprofen-loaded rectal pharmaceutical products.     

Folate-mediated poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) nanoparticles for targeting drug delivery

A novel targeting drug delivery system (TDDS) has been developed. Such a TDDS was prepared by W₁/O/W₂ solvent extraction/evaporation method, adopting poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) [P(HB-HO)] as the drug carrier, folic acid (FA) as the targeting ligand, and doxorubicin (DOX) as the model anticancer drug. The average size, drug loading capacity and encapsulation efficiency of the prepared DOX-loaded, folate-mediated P(HB-HO) nanoparticles (DOX/FA–PEG–P(HB-HO) NPs) were found to be around 240 nm, 29.6% and 83.5%. The in vitro release profile displayed that nearly 50% DOX was released in the first 5 days. The intracellular uptake tests of the nanoparticles (NPs) in vitro showed that the DOX/FA–PEG–P(HB-HO) NPs were more efficiently taken up by HeLa cells compared to non-folate-mediated P(HB-HO) NPs. In addition, DOX/FA–PEG–P(HB-HO) NPs (IC₅₀ = 0.87 μM) showed greater cytotoxicity to HeLa cells than other treated groups. In vivo anti-tumor activity of the DOX/FA–PEG–P(HB-HO) NPs showed a much better therapeutic efficacy in inhibiting tumor growth, and the final mean tumor volume was 178.91 ± 17.43 mm³, significantly smaller than normal saline control group (542.58 ± 45.19 mm³). All these results have illustrated that our techniques for the preparing of DOX/FA–PEG–P(HB-HO) NPs developed in present work are feasible and these NPs are effective in selective delivery of anticancer drug to the folate receptor-overexpressed cancer cells. The new TDDS may be a competent candidate in application in targeting treatment of cancers.     

Principles of rational design of thermally targeted liposomes for local drug delivery

Drug release from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes occurs close to the main transition temperature T_m = 41 °C. The exact release temperature can be adjusted by additional lipids, which shift T_m. A major issue is drug leakage at 37 °C. We here describe a novel approach with improved drug retention yet rapid release. To obtain spherical, smooth liposomes we included: i) 2 mol% cholesterol, to soften bilayers (Lemmich et al 1997), ii) lipids, which due to their spontaneous curvature stabilize the negative and positive curvatures of the inner and outer leaflets of unilamellar liposomes. In addition to differential scanning calorimetry (DSC) and fluorescence spectroscopy, the lipid mixtures were analyzed by a Langmuir balance for their elastic properties and lipid packing, aiming at high elasticity modulus C_S^− 1. Maxima in C_S^− 1 coincided with minima in the free energy of lateral mixing. These liposomes have reduced drug leakage, yet retain rapid release.From the Clinical EditorThis paper reports the development of optimized DPPC liposomes for drug delivery, with reduced drug leakage but maintained rapid release.     

Study of the stability of packaging and storage conditions of human mesenchymal stem cell for intra-arterial clinical application in patient with critical limb ischemia

Critical limb ischemia (CLI) is associated with significant morbidity and mortality. In this study, we developed and characterized an intra-arterial cell suspension containing human mesenchymal stem cells (hMSCs) for the treatment of CLI. Equally, the stability of cells was studied in order to evaluate the optimal conditions of storage that guarantee the viability from cell processing to the administration phase. Effects of various factors, including excipients, storage temperature and time were evaluated to analyze the survival of hMSCs in the finished medicinal product. The viability of hMSCs in different packaging media was studied for 60 h at 4 °C. The best medium to maintain hMSCs viability was then selected to test storage conditions (4, 8, 25 and 37 °C; 60 h). The results showed that at 4 °C the viability was maintained above 80% for 48 h, at 8 °C decreased slightly, whereas at room temperature and 37 °C decreased drastically. Its biocompatibility was assessed by cell morphology and cell viability assays. During stability study, the stored cells did not show any change in their phenotypic or genotypic characteristics and physicochemical properties remained constant, the ability to differentiate into adipocytes and osteocytes and sterility requirements were also unaltered. Finally, our paper proposes a packing media composed of albumin 20%, glucose 5% and Ringer’s lactate at a concentration of 1 × 10⁶ cells/mL, which must be stored at 4 °C as the most suitable to maintain cell viability (>80%) and without altering their characteristics for more than 48 h.     

PHARMACEUTICAL NANOTECHNOLOGY: A Novel Composite Hydrogel Based on Chitosan and Inorganic Phosphate for Local Drug Delivery of Camptothecin Nanocolloids

In attempt to overcome the problem of low water solubility and severe toxicity of camptothecin (CPT) after intravenous administration, a novel drug carrier system based on chitosan (CS) and dibasic sodium phosphate (DSP) has been developed in this paper to encapsulate CPT intending for local administration. Nanocolloids of CPT with size about 500 nm were first prepared, followed by encapsulation in the chitosan/dibasic sodium phosphate (CS/DSP) formulation. The formulation was sol state below 37°C and transformed to nonflowing gel state at 37°C. Encapsulation of CPT nanocolloids had greatly effect on the gelling time as well as the micro-structure of hydrogel. In vitro and in vivo degradation studies revealed that the developed CS/DSP hydrogel was biodegradable and biocompatible. In vitro release study revealed that CPT released from CS/DSP hydrogel in an extended period with about 70% of total CPT released from hydrogel after 18 days. Furthermore, nearly 90% of CPT in the chitosan hydrogels could be preserved in the lactone form (active form) even after 7 days's storage at 37°C. Furthermore, in vitro cytotoxicity of CPT nanocolloids on SKOV3 human ovarian cancer cells suggested the well anti-tumor cell efficiency could be gained at a lower concentration.     

Development and statistical optimization of nefopam hydrochloride loaded nanospheres for neuropathic pain using Box–Behnken design

Nefopam hydrochloride (NFH) is a non-opioid centrally acting analgesic drug used to treat chronic condition such as neuropathic pain. In current research, sustained release nefopam hydrochloride loaded nanospheres (NFH-NS) were auspiciously synthesized using binary mixture of eudragit RL 100 and RS 100 with sorbitan monooleate as surfactant by quasi solvent diffusion technique and optimized by 3⁵ Box–Behnken designs to evaluate the effects of process and formulation variables. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetric (DSC) and X-ray diffraction (XRD) affirmed absence of drug–polymer incompatibility and confirmed formation of nanospheres. Desirability function scrutinized by design-expert software for optimized formulation was 0.920. Optimized batch of NFH-NS had mean particle size 328.36 nm ± 2.23, % entrapment efficiency (% EE) 84.97 ± 1.23, % process yield 83.60 ± 1.31 and % drug loading (% DL) 21.41 ± 0.89. Dynamic light scattering (DLS), zeta potential analysis and scanning electron microscopy (SEM) validated size, charge and shape of nanospheres, respectively. In-vitro drug release study revealed biphasic release pattern from optimized nanospheres. Korsmeyer Peppas found excellent kinetics model with release exponent less than 0.45. Chronic constricted injury (CCI) model of optimized NFH-NS in Wistar rats produced significant difference in neuropathic pain behavior (p < 0.05) as compared to free NFH over 10 h indicating sustained action. Long term and accelerated stability testing of optimized NFH-NS revealed degradation rate constant 1.695 × 10⁻⁴ and shelf-life 621 days at 25 ± 2 °C/60% ± 5% RH.     

Incubation at 32.5 °C and above causes malformations in the zebrafish embryo

Zebrafish embryos are increasingly used for developmental toxicity screening of candidate drugs and are occasionally co-incubated with a metabolic activation system at 32 °C for 1, 2 or 4 h, depending on their developmental stage. As this temperature is higher than the optimal temperature for zebrafish embryonic development (26–28.5 °C), we investigated whether continuous incubation of zebrafish embryos from 2.5 until 96 h post fertilization (hpf) at high temperatures (30.5–36.5 °C) causes malformations. At 32.5 °C tail malformations were observed as early as 24 hpf, and these became even more prominent at 34.5 and 36.5 °C. Cardiovascular and head malformations, edema and blood accumulations throughout the body were present at 36.5 °C. Finally, temperatures higher than 28.5 °C accelerated embryonic development except for 36.5 °C, at which a lower hatching rate and hatching enzyme activity were observed. In conclusion, incubation of zebrafish embryos at 32.5 °C and above from 2.5 until 96 hpf causes malformations as early as 24 hpf.     

Compatibility and Stability of Pertuzumab and Trastuzumab Admixtures in i.v. Infusion Bags for Coadministration

The physical/chemical stability and potential interactions after diluting two immunoglobulin G1 monoclonal antibodies (mAb), pertuzumab (Perjeta®) and trastuzumab (Herceptin®), in a single intravenous (i.v.) infusion bag containing 0.9% saline (NaCl) solution was evaluated. As commercial products, pertuzumab and trastuzumab are administered through i.v. infusion to patients sequentially, that is, one drug after the other. To increase convenience and minimize the in-clinic time for patients, the compatibility of coadministering pertuzumab (420 and 840 mg) mixed with either 420 or 720 mg trastuzumab, respectively, in a single 250 mL polyolefin or polyvinyl chloride i.v. bag stored for up to 24 h at 5°C or 30°C was determined. The controls (i.e., pertuzumab alone in an i.v. bag, trastuzumab alone in an i.v. bag) and the mAb mixture were assessed using color, appearance, and clarity, concentration and turbidity by ultraviolet spectroscopy, particulate analysis by light obscuration, size-exclusion chromatography, capillary electrophoresis-sodium dodecyl sulfate, analytical ultracentrifugation, and ion-exchange chromatography. Additionally, capillary zone electrophoresis, imaged capillary isoelectric focusing, and potency were utilized to measure the stability of the admixtures containing 1:1 mixtures of pertuzumab/trastuzumab and their respective controls (420 mg pertuzumab alone and 420 mg trastuzumab alone). No observable differences were detected by the above methods in the pertuzumab/trastuzumab mixtures stored up to 24 h at either 5°C or 30°C. The physicochemical methods as listed above were able to detect both molecules as well as the minor variants in the drug mixture, even though some overlap of mAb species were seen in the chromatograms and electropherograms. Furthermore, biophysical analysis also did not show any interactions between the two mAbs or any physical instability under these conditions. Additionally, the drug mixture tested by the pertuzumab-specific inhibition of cell proliferation bioassay showed comparable potency before and after storage. On the basis of these results, pertuzumab and trastuzumab admixture in a single i.v. bag is physically and chemically stable for up to 24 h at 5°C or 30°C and can be used for clinical administration. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:794–812, 2013     

Formulation and stability of a novel artificial human sweat under conditions of storage and use

A limitation of most artificial sweat formulations used for in vitro assessment of chemical release from materials in contact with skin have little biological relevance to human sweat. The purposes of this paper are to provide guidance for preparation of a novel artificial sweat with chemical constituents at concentrations that match human sweat and to characterize chemical stability. The artificial sweat was characterized under conditions of use (with and without sebum at 36 °C) and storage (without sebum at −4, 4, and 23 °C) over 28 days by gas chromatography–mass spectroscopy, high-performance liquid chromatography, enzymatic assay kits, and ion-selective electrodes. Seven indicator constituents were tracked: sodium, chloride, glucose, lactic acid, urea, pantothenic acid, and alanine. With or without sebum at 36 °C, the sweat solvent was chemically stable for 14 days. Storage by refrigeration at 4 °C retained the chemical integrity of the solvent longest. Based on these results, the solvent should be used within 14 days of preparation. The artificial sweat model presented herein is most similar to human sweat and has applications as a dissolution solvent, donor solution in diffusion cells, or vehicle for patch testing. This sweat model may aid researchers in understanding potential release and percutaneous absorption of chemicals in contact with human skin surface liquids.     

Lopinavir loaded solid lipid nanoparticles (SLN) for intestinal lymphatic targeting

The poor orally available lopinavir was successfully encapsulated in glyceryl behenate based solid lipid nanoparticles (Lo-SLN) for its ultimate use to target intestinal lymphatic vessels in combined chemotherapy—the so-called Highly Active Anti-Retroviral Therapy (HAART). SLN with mean particle size of 230 nm (polydispersity index, PDI < 0.27) and surface electrical charge of approx. ?27 mV, were produced by hot homogenization process followed by ultrasonication. Particles were characterized using differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS) and atomic force microscopy (AFM) to confirm their solid character and the homogeneous distribution of drug within the lipid matrix. In vitro release studies at pH 6.8 phosphate buffer (PBS) and at pH 1.2 HCl 0.1 N showed a slow release in both media. From the intestinal lymphatic transport study it became evident that SLN increased the cumulative percentage dose of lopinavir secreted into the lymph, which was 4.91-fold higher when compared with a conventional drug solution in methyl cellulose 0.5% (w/v) as suspending agent (Lo-MC). The percentage bioavailability was significantly enhanced. The AUC for the Lo-SLN was 2.13-fold higher than that obtained for the Lo-MC of similar concentration. The accelerated stability studies showed that there was no significant change in the mean particle size and PDI after storage at 25 ± 2 °C/60 ± 5% RH. The shelf life of optimized formulation was assessed based on the remained drug content in the stabilized formulation and was shown to be 21.46 months.     

Changes in ambient temperature differentially alter the thermoregulatory,cardiac and locomotor stimulant effects of 4-methylmethcathinone (mephedrone)

BackgroundThe substituted cathinone compound known as mephedrone (4-methylmethcathinone; 4-MMC) has become popular with recreational users of psychomotor-stimulant compounds. Only recently have the first preclinical studies provided information about this drug in the scientific literature; nevertheless, media reports have led to drug control actions in the UK and across several US states. Rodent studies indicate that 4-MMC exhibits neuropharmacological similarity to 3,4-methylenedioxymethamphetamine (MDMA) and prompt investigation of the thermoregulatory, cardiac and locomotor effects of 4-MMC. This study focuses on the role of ambient temperature, which has been shown to shift the effects of MDMA from hyperthermic to hypothermic.MethodsMale Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1.0–5.6 mg/kg) using an implantable radiotelemetry system under conditions of low (20 °C) and high (30 °C) ambient temperature.ResultsA pharmacokinetic study found a T_max of 0.25 h and a C_max of 1206 ng/ml after 5.6 mg/kg 4-MMC. A dose-dependent reduction of body temperature was produced by 4-MMC at 20 °C but there was no temperature change at 30 °C. Increased locomotor activity was observed after 4-MMC administration under both ambient temperatures, however, significantly more activity was observed at 30 °C. Heart rate was slowed by 1.0 and 5.6 mg/kg 4-MMC at 20 °C, and was slower in the 30 °C vs. 20 °C condition across all treatments.ConclusionThese results show that the cathinone analog 4-MMC exhibits in vivo thermoregulatory properties that are distinct from those produced by MDMA.     

Supramolecular gels of poly-α-cyclodextrin and PEO-based copolymers for controlled drug release

The aim of this work was to prepare syringeable supramolecular gels of α-cyclodextrin-polymer (poly-αCD) with various poly(ethylene oxide) (PEO)-based copolymers, which can be suitable to form depots for controlled drug release. A series of water-soluble poly-αCDs was synthesized from αCD by crosslinking with epichlorohydrin in alkaline medium. The chemical composition of the polymers was characterized by NMR (αCD content > 53%) and the molecular weight was evaluated using static light scattering (SLS). Supramolecular assemblies occurred by mixing poly-αCD (20–40% w/v) with a PEO-based polymer (i.e., PEG, Pluronic® F127 or Tetronic® 908) (10–15% w/v). Phase separation was observed and the αCD content in each phase was determined by means of the phenol–sulfuric acid colorimetric method. Formation of poly-αCD/PEO-based polymer 3D-supramolecular complexes was confirmed by diffusion-ordered NMR spectroscopy (DOSY) and X-ray diffractometry. The supramolecular assemblies showed good cytocompatibility against SAOS-2 cells and in the HET-CAM test. The supramolecular gels were able to sustain the release of vancomycin for at least 5 days at 37 °C, more efficiently than dispersions of each polymer component in separate. These results open new possibilities in the design of novel controlled delivery systems for the treatment of bone infections.     

Development of doxorubicin-induced chronic cardiotoxicity in the B6C3F1 mouse model

Serum levels of cardiac troponins serve as biomarkers of myocardial injury. However, troponins are released into the serum only after damage to cardiac tissue has occurred. Here, we report development of a mouse model of doxorubicin (DOX)-induced chronic cardiotoxicity to aid in the identification of predictive biomarkers of early events of cardiac tissue injury. Male B6C3F₁ mice were administered intravenous DOX at 3 mg/kg body weight, or an equivalent volume of saline, once a week for 4, 6, 8, 10, 12, and 14 weeks, resulting in cumulative DOX doses of 12, 18, 24, 30, 36, and 42 mg/kg, respectively. Mice were sacrificed a week following the last dose. A significant reduction in body weight gain was observed in mice following exposure to a weekly DOX dose for 1 week and longer compared to saline-treated controls. DOX treatment also resulted in declines in red blood cell count, hemoglobin level, and hematocrit compared to saline-treated controls after the 2nd weekly dose until the 8th and 9th doses, followed by a modest recovery. All DOX-treated mice had significant elevations in cardiac troponin T concentrations in plasma compared to saline-treated controls, indicating cardiac tissue injury. Also, a dose-related increase in the severity of cardiac lesions was seen in mice exposed to 24 mg/kg DOX and higher cumulative doses. Mice treated with cumulative DOX doses of 30 mg/kg and higher showed a significant decline in heart rate, suggesting drug-induced cardiac dysfunction. Altogether, these findings demonstrate the development of DOX-induced chronic cardiotoxicity in B6C3F₁ mice.     

An in vitro approach to assessing a potential drug interaction between MDMA (ecstasy) and caffeine

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a popular recreational drug which causes long-term neurotoxicity and increased risk of fatality. In rats, MDMA toxicity is exacerbated by co-administration of caffeine. The aim of this study was to investigate whether caffeine altered the effects of MDMA in a battery of in vitro tests selected to model some of the known actions of MDMA in vivo. In cytotoxicity studies, caffeine modestly enhanced the effect of MDMA on neuronal N2a cell viability but not that of liver, intestinal or kidney cells. MDMA inhibited the formation of fluorescent metabolites by CYP2D6 ≫ CYP3A4 > CYP1A2 but this was not altered by caffeine. Similarly, the inhibition of synaptosomal [³H] 5-HT uptake by MDMA was not affected by the presence of caffeine. Thus, these in vitro tests failed to detect any substantial interaction between caffeine and MDMA, highlighting the difficulty of modelling in vivo drug interactions using in vitro tests. However, the results show that the inhibition of synaptosomal [³H] 5-HT uptake by MDMA was greater at 41 °C and 25 °C than at 37 °C which raises the possibility that MDMA’s effect on SERT in vivo may be increased as body temperature increases, contributing to its harmful effects in users.     

Oseltamivir Phosphate–Amberlite™ IRP 64 Ionic Complex for Taste Masking: Preparation and Chemometric Evaluation

The objective of the present work was to evaluate and characterize a pediatric- friendly formulation of a bitter tasting drug, oseltamivir phosphate (drug). Amberlite IRP64 (resin) was used to make ionic complexes for masking its bitterness. Complexes of four drug-to-resin ratios, 1:1, 1:2, 1:4, and 1:6 (w/w), were prepared and characterized. At buccal pH of 6.8, drug–resin complexes of 1:1,1:2,1:4, and 1:6 ratios released 42.13%, 23.26%, 4.13%, and 14.94%, respectively, of loaded drug after 20 s. However, at stomach pH of 1.2 (0.1 N HCl), 61.96%, 70.18%, 85.88%, and 91.42% of drug was released from the same complexes in 6 min. Near-infrared (NIR) chemical imaging of the complexes showed homogeneous distribution of drug in the resin. Chemometric partial least squares model using NIR data of the drug showed a high correlation between calibration and predicted data(R² > 0.998). Overall, these results indicated the complex formation between drug and resin. The pH dependence of drug release from these complexes could minimize drug release in the mouth, whereas immediately releasing it in the stomach. Electronic tongue used to evaluate taste indicated that conductivity taste signals were different from control, suggesting taste masking of the drug.     

Investigation of PEG Crystallization in Frozen PEG-Sucrose-Water Solutions. I. Characterization of the Nonequilibrium Behavior during Freeze-Thawing

Our objective was to characterize the nonequilibrium thermal behavior of frozen aqueous solutions containing PEG and sucrose. Aqueous solutions of (i) sucrose (10%, w/v) with different concentrations of PEG (1–20%, w/v), and (ii) PEG (10%, w/v) with different concentrations of sucrose (2–20%, w/v), were cooled to ? 70°C at 5°C/min and heated to 25°C at 2°C/min in a differential scanning calorimeter. Annealing was performed at temperatures ranging from ? 50 to ? 20°C for 2 or 6 h. Similar experiments were also performed in the low-temperature stage of a powder X-ray diffractometer. A limited number of additional DSC experiments were performed wherein the samples were cooled to ? 100°C. In unannealed systems with a fixed sucrose concentration (10%, w/v), the T′_g decreased from ? 35 to ? 48°C when PEG concentration was increased from 1% to 20% (w/v). On annealing at ? 25°C, PEG crystallized. This was evident from the increase in T′_g and the appearance of a secondary melting endotherm in the DSC. Low- temperature XRD provided direct evidence of PEG crystallization. Annealing at temperatures ≤?40°C did not result in crystallization and a devitrification event was observed above the T′_g. In unannealed systems with a fixed PEG concentration (10%, w/v), the T′_g increased from ? 50 to ? 40°C when sucrose concentration was increased from 5% to 50%, w/v. As the annealing time increased (at ? 25°C), the T′_g approached that of a sucrose-water system, reflecting progressive PEG crystallization. A second glass transition at ~? 65°C was evident in unannealed systems [10%, w/v sucrose and 10 (or 20%), w/v PEG] cooled to ? 100°C. Investigation of the nonequilibrium behavior of frozen PEG-sucrose-water ternary system revealed phase separation in the freeze-concentrate. Annealing facilitated PEG crystallization.     

Synergism Between Propolis and Hyperthermal Intraperitoneal Chemotherapy with Cisplatin on Ehrlich Ascites Tumor in Mice

We investigated antitumor, genotoxic, chemopreventive, and immunostimulative effects of local chemoimmunotherapy and hyperthermal intraperitoneal chemotherapy (HIPEC) in a mouse-bearing Ehrlich ascites tumor (EAT). Mice were treated with water-soluble derivative of propolis (WSDP) at a dose of 50 mg kg^? 1, 7 and 3 days before implantation of EAT cells, whereas cisplatin (5 or 10 mg kg^? 1) was injected 3 days after implantation of EAT cells at 37°C and 43°C. The following variables were analyzed: the total number of cells, differential count of the cells present in the peritoneal cavity, functional activity of macrophages, comet assay, and micronucleus assay. The combination of WSDP + CIS 5 mg kg^? 1 at 37°C resulted in tumor growth inhibition and increased the survival of mice by additional 115.25%. WSDP with HIPEC increased the survival of mice by additional 160.3% as compared with HIPEC. WSDP reduced cisplatin toxic and genotoxic effect to normal cells without affecting cisplatin cytotoxicity on EAT cells. In addition, WSDP with HIPEC increased the cytotoxic actions of macrophages to tumor cells. Water-soluble derivative of propolis increases macrophage activity and sensitivity of tumor cells to HIPEC and reduces cisplatin toxicity to normal cells.