Exploring the analytical power of the QTOF MS platform to assess monoclonal antibodies quality attributes

The biopharmaceutical industry is growing at a fast pace, making nowadays 20% of the pharma market. Within this market, therapeutic monoclonal antibodies (mAbs) are the dominant product class. With the patent expirations, biosimilars and, perhaps more relevant, biobetters, are in fast development. Thus, a comprehensive characterization at the molecular level of antibodies heterogeneity such as glycoforms, post-translational modifications (PTMs) and sequence variations is of utmost importance. Mass spectrometry (MS)-based approaches are undoubtedly the most powerful analytical strategies to monitor and define an array of critical quality attributes on mAbs. In this work, we demonstrate the analytical power of the Q-TOF MS platform for comprehensive and detailed analysis at molecular levels of an in-house produced mAb. This methodology involves minimal sample preparation procedures and provides an extensive collection of valuable data in a short period of time.

Recovery of antioxidant and antiproliferative compounds from watercress using pressurized fluid extraction

The potential of pressurized fluid technology to isolate bioactive antioxidant and antiproliferative compounds from watercress was studied.

Fullerenol C60(OH)24 prevents doxorubicin-induced acute cardiotoxicity in rats

Results obtained in vitro suggested that fullerenol's antiproliferative properties and protective effects against doxorubicin (DOX) cytotoxicity are mediated by antioxidative and hydroxyl radical scavenger activity. The aim of this study was to examine the influence of fullerenol on acute cardiotoxicity after the administration of a single high dose of DOX in vivo. The experiment was performed on male Wistar rats randomly divided into five groups, each containing eight individuals, that were treated as follows: I) 0.9% NaCl, II) 10 mg/kg DOX, III) 50 mg/kg fullerenol 30 min before 10 mg/kg DOX, IV) 100 mg/kg fullerenol 30 min before 10 mg/kg DOX, and V) 100 mg/kg fullerenol. A functional, biochemical, hematological, and pathomorphological examination of the heart as well as an evaluation of oxidative stress parameters was conducted on days 2 and 14 after DOX administration. The function of the heart was investigated by monitoring heart contractility after the adrenaline infusion. Fullerenol, applied alone, did not alter basal values of investigated animals. Both doses of fullerenol, used as a pretreatment, did not alter the basal parameters of the animals. The 100 mg/kg dose of fullerenol showed better protection. Considering the mechanisms of DOX toxicity, fullerenol likely exerts its protective role as a free radical sponge and/or by removing free iron through the formation of a fullerenol-iron complex. Our results suggest that fullerenol might be a potential cardioprotective agent in DOX-treated individuals.

Detection and quantification of carboxylesterase 2 activity by capillary electrophoresis

The purpose of this study was to develop an analytical method to quantify the relative activities of carboxylesterases (CESs) in biological samples. Taking the advantage of loperamide, a specific carboxylesterase 2 (CES2) inhibitor, and bis-p-nitrophenyl phosphate (BNPP), an irreversible CESs inhibitor, we propose for the first time a capillary electrophoresis (CE) method that enables detecting and distinguishing CES2 activity from other CESs in complex biological samples. The capillary electrophoresis method proved to be fast, simple, repeatable, and applicable to the measurement of the specific activity of CESs. The method was successfully applied to the evaluation of human cells overexpressing human carboxylesterase 2 (hCE-2) and to several mammalian sera, using extremely small amounts of samples in comparison with traditional spectrophotometric methods. The same rationale can be applied to establish methods for determining the activity of other isoenzymes, using the appropriate specific inhibitors.

Dopamine- and tyramine-based derivatives of triazenes: activation by tyrosinase and implications for prodrug design

A range of triazene derivatives were synthesized and investigated as prodrug candidates for melanocyte-directed enzyme prodrug therapy (MDEPT). The prodrugs contained a tyramine or dopamine promoiety required for tyrosinase activation and this was joined via a urea functional group to the cytotoxic triazene. The stability of each of the prodrugs in phosphate buffer, human plasma and in mushroom tyrosinase is discussed. The identification of the main peak formed after the tyrosinase reaction was attempted by LC-MS and the conversion of prodrug to the quinone was confirmed.

β-Aminoketones as prodrugs with pH-controlled activation

N-Mannich bases have been widely applied as prodrugs of amine drugs. The analogous C-Mannich bases (beta-aminoketones) have received rather less attention probably because they are not sufficiently susceptible to elimination at pHs encountered in vivo. Compounds in which there is a thermodynamic advantage to elimination may be an exception. In this study, the physicochemical characteristics of a series of Michael amino addition adducts of chalcone and other carbonyl compounds is explored. The ketone adducts rapidly eliminate at around pH 7.4 (t(1/2) < 15 min) releasing the amine and the ketone but they are stable under acidic conditions. The Michael adducts are more lipophilic than the parent amines and have significantly suppressed ionisation characteristics at biologically relevant pH values.

Chiral separation and identification of β-aminoketones of pharmacological interest by high performance liquid chromatography and capillary electrophoresis

This paper describes the development and comparison of chiral methods of analysis for a series of pharmacologically active indane derivatives that have been studied in the context of the evaluation of a promising prodrug system for amines. The methods are intended for studying the differences in the pharmacokinetics of the optical isomers of these compounds. Capillary electrophoresis, using cyclodextrins as chiral selectors, and HPLC, using a Pirkle type stationary phase, were tested. Baseline separation was not achieved by HPLC, but good separations were obtained in less than 7 min, by capillary electrophoresis with phosphate buffers pH 2.5-3 using sulfated-beta-cyclodextrin or mixtures of neutral beta-cyclodextrins as chiral selectors.

Preparation of ethyl cellulose/methyl cellulose blends by supercritical antisolvent precipitation

The supercritical antisolvent (SAS) technique was used to prepare ethyl cellulose/methyl cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as methyl cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 microm were obtained. The effect of CO(2) and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and dimethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 degrees C and 80 bar.

Preparation of controlled release microspheres using supercritical fluid technology for delivery of anti-inflammatory drugs

Ethylcellulose/methylcellulose blends were produced using different precipitation techniques and impregnated with naproxen, a non-steroidal anti-inflammatory drug (NSAID). Solvent-evaporation technique was used not only for the preparation of ethylcellulose/methylcellulose microspheres but also to encapsulate naproxen. Supercritical fluid (SCF) impregnation was also performed to prepare naproxen loaded microspheres. The microspheres, impregnated by the SCF technique, were prepared both by solvent-evaporation and by a supercritical antisolvent (SAS) process. In vitro release profiles at pH 7.4 and 1.2, of naproxen-loaded microspheres were evaluated and the results were modelled Fick's law of diffusion and Power law. Miscrospheres prepared by supercritical antisolvent have a higher loading capacity and present a slower release profile. The systems studied present a release mechanism controlled by drug diffusion which complies Fick's law of diffusion.

A new amino-masking group capable of pH-triggered amino-drug release

The prodrug approach is potentially useful for mitigating pharmaceutical problems--such as poor membrane permeability or stability--which commonly occur with amino drugs. On the other hand there persists a dearth of useful systems for masking amines that satisfy the prodrug requirements of good in vitro stability coupled with predictable and rapid drug release in response to a local tissue condition. This study describes an evaluation of aminoindanes as bioreversibly masked amines poised to undergo elimination to the parent amine. Several model amine and amino drug indanone derivatives were synthesised. pK(a) values were determined by capillary electrophoresis and pH rate profiles for elimination and amine liberation were measured. The aminoindanone system appears to have particular applicability to secondary amino substrates whose indanone derivatives are stable at low pH but undergo drug release at rates corresponding to first-order half-lives of <5 min at pH 7.4.

Ionisation characteristics and elimination rates of some aminoindanones determined by capillary electrophoresis

Capillary electrophoresis (CE) has emerged as an important tool for evaluating the ionisation characteristics of compounds and their corresponding pKa values. A particular strength of CE in this context is that its relative selectivity allows one to measure the extent of ionisation of materials that are impure. In this study, using CE, we have measured the pKa values of a series of anti-inflammatory aminoindanones, which underwent degradation to indenone during the course of the determination. We subsequently monitored the elimination reactions measuring remaining indanone over the pH range 2.6-10 at constant ionic strength and temperature. The decomposition of the tertiary amino derivatives was especially fast with first-order half-lives of less than 10 min observed at pH 7.4. The resulting sigmoidal pH rate profiles can be accounted for by assuming unimolecular elimination of the protonated (slow) and neutral (fast) forms of the amines. This study provides further support for the use of CE in evaluating amino ionisation especially in cases where degradation might be expected.

Validation of a solid-phase microextraction method for the determination of organophosphorus pesticides in fruits and fruit juice

A method for the determination of organophosphorus pesticides (diazinon, fenitrothion, fenthion, quinalphos, triazophos, phosalon and pyrazophos) in fruit (pears) and fruit juice samples was developed and validated. The samples were diluted with water, extracted by solid-phase microextraction (SPME) and analysed by gas chromatography (GC) using a flame photometric detector in phosphorous mode. Limits of detection of the method for fruit and fruit juice matrices were below 2 micrograms/kg for all pesticides. Relative standard deviations for triplicate analyses of samples fortified at 25 micrograms/kg of each pesticide were not higher than 8.7%. Recovery tests were performed for concentrations between 25 and 250 micrograms/kg. Mean recoveries for each pesticide were all above 75.9% and below 102.6% for juice, and between 70 and 99% for fruit except for pyrazophos in the fruit sample (with mean recovery of 53%). Therefore, the proposed method is applicable in the analysis of pesticides in fruit matrices and the use of the method in routine analysis of pesticide residues is discussed.