A highly sensitive fluorimetric method for determination of lenalidomide in its bulk form and capsules via derivatization with fluorescamine

Wearable Sensors for the Detection of Biomarkers for Wound Infection

Infection represents a major complication that can affect wound healing in any type of wound, especially in chronic ones. There are currently certain limitations to the methods that are used for establishing a clinical diagnosis of wound infection. Thus, new, rapid and easy-to-use strategies for wound infection diagnosis need to be developed. To this aim, wearable sensors for infection diagnosis have been recently developed. These sensors are incorporated into the wound dressings that are used to treat and protect the wound, and are able to detect certain biomarkers that can be correlated with the presence of wound infection. Among these biomarkers, the most commonly used ones are pH and uric acid, but a plethora of others (lactic acid, oxygenation, inflammatory mediators, bacteria metabolites or bacteria) have also been detected using wearable sensors. In this work, an overview of the main types of wearable sensors for wound infection detection will be provided. These sensors will be divided into electrochemical, colorimetric and fluorimetric sensors and the examples will be presented and discussed comparatively.

Development of 96-microwell Plate Assay with Fluorescence Reader and HPLC Method with Fluorescence Detection for High-throughput Analysis of Linifanib in its Bulk and Dosage Forms

Background:

Linifanib (LFB) is a tyrosine kinase inhibitor with antineoplastic activity. The existing methods for the analysis of LFB in bulk and dosage forms do not meet the requirements of quality control (QC) analysis.

Objective:

The present study was devoted to the development of two methods with high throughputs for determination of LFB. These methods are 96-microwell plate assay with microplate fluorescence reader (MWP-FR) and high-performance liquid chromatography with fluorescence detection (HPLC-FD).

Methods:

The MWP-FR assay was carried out in white opaque 96-well assay plates and the native fluorescence signals of LFB were measured at 360 nm for excitation and 500 nm for emission. In the HPLC-FD, the chromatographic separation of LFB and quinine sulphate (QS) as internal standard (IS) was performed on µ-Bondapack CN HPLC column using a mobile phase consisting of acetonitrile:water (60:40, v/v) pumped at a flow rate of 1 ml/min in an isocratic mode. The fluorescence detector was set at 350 nm for excitation and 454 nm for emission.

Results:

The linear ranges of the MWP-FR and HPLC-FD were 1-12 µg/well and 10-500 ng/ml, respectively. The limits of detection were 0.85 µg/well and 8.24 ng/ml for MWP-FR and HPLC-FD, respectively. Both MWP-FR and HPLC-FL methods were successfully applied for the determination of LFB in both bulk and tablets.

Conclusion:

Both methods have high analytical throughputs, they are suitable for use in QC laboratories for analysis of large numbers of LFB samples, and are environmentally friendly as they consume low volumes of chemicals and solvents.

Development and validation of a liquid chromatography-tandem mass spectrometric method for the determination of lenalidomide in human plasma and its application on bioequivalence studies

A simple, sensitive, and specific liquid chromatography-tandem mass spectrophotometry (LC-MS/MS) method was developed and validated for the quantification of lenalidomide in human plasma. The separation was carried out on a symmetry, C18, 5-μm (50 × 4.6 mm) column as stationary phase and with an isocratic mobile phase of 0.1% formic acid in water-methanol in the ratio of (15:85, v/v) at a flow rate of 0.5 mL/min. Protonated ions formed by electrospray ionization in the positive mode were used to detect analyte and fluconazole (internal standard). The mass detection was made by monitoring the fragmentation of m/z 260.1/148.8 for lenalidomide and m/z 307.1/238.0 for internal standard on a triple quadrupole mass spectrometer. The developed method was validated over the concentration range of 10–1000 ng/mL for lenalidomide in human plasma with a correlation coefficient (r2) was 0.9930. The accuracy and precision values obtained from six different sets of quality control samples analyzed on separate occasions ranged from 99.41 to 106.97% and 2.88 to 4.22%, respectively. Mean extraction recoveries were 98.06% and 88.78% for the analyte and IS, respectively. The developed method was successfully applied for analyzing lenalidomide in human plasma samples.

A Validated Stability-Indicating and Stereoselective HPLC Method for the Determination of Lenalidomide Enantiomers in Bulk Form and Capsules

A simple, rapid and stability-indicating chiral HPLC (CHR-HPLC) method was designed for the enantiomeric separation of lenalidomide (LDM) in the presence of its degradation products. LDM was exposed to different accelerated stress factors. The degradation products were well resolved from the pure drug enantiomers. Separation of the LDM enantiomers was achieved on a LUX 5U cellulose-2 chiral column (250 × 4.6 mm i.d.) with a mobile phase consisting of methanol : glacial acetic acid : triethyl amine (100 : 0.01 : 0.01, v/v/v) at a flow rate of 1.2 mL/min. The detection wavelength was 220 nm, and ornidazole was the internal standard. The chiral method was validated in terms of its specificity, linearity, range, precision and accuracy as well as solution stability, robustness, limit of detection and limit of quantification. The calibration curve was linear for concentrations ranging from 2 to 1,000 ng/mL (r= 0.9999) for both LDM enantiomers. The proposed method, which met International Conference on Harmonization/Food and Drug Administration regulatory requirements, was utilized successfully for the determination of LDM in bulk and in capsules with acceptable accuracy and precision; the label demand percentages were 100.09 ± 0.80 and 99.97 ± 0.93 for the S-(-) and R-(+)-LDM enantiomers, respectively. Based on these results, this method should have great value when applied to quality control and stability studies of LDM.

Trace determination of lenalidomide in plasma by non-extractive HPLC procedures with fluorescence detection after pre-column derivatization with fluorescamine

BACKGROUND

Lenalidomide (LND) is a new potent drug used for treatment of multiple myeloma. For its pharmacokinetic studies and therapeutic monitoring, a proper analytical method was required.

RESULTS

In this study, a non extractive and simple pre-column derivatization procedures have been proposed, for the for trace determination of lenalidomide (LND) in human plasma by HPLC with fluorescence detection. Plasma samples were treated with acetonitrile for protein precipitation then treated with copper acetate to form stable complexes with the biogenic amines and mask their interference with the derivatization reaction of LND. Treated plasma samples containing LND was derivatized with fluorescamine (FLC) in aqueous media at ambient temperature. Separation of the derivatized LND was performed on Hypersil BDS C18 column (250 × 4.6 mm, 5 μm particle size) using a mobile phase consisting of phosphate buffer (pH 4):methanol: tetrahydrofuran (70:10:20, v/v) at a flow rate of 1.0 mL/min. The derivatized samples were monitored at an emission wavelength of 495 nm after excitation at a wavelength of 382 nm. Under the optimum chromatographic conditions, a linear relationship with good correlation coefficient (r = 0.9997, n = 9) was found between the peak area and LND concentrations in the range of 2-100 ng/mL. The limits of detection and quantitation were 0.8 and 2.30 ng/mL, respectively. The intra- and inter-assay precisions were satisfactory and the accuracy of the method was proved. The recovery of LND from the spiked human plasma was 99.30 ± 2.88.

CONCLUSIONS

The proposed method had high throughput as the analysis involved simple sample pre-treatment procedure and a relatively short run-time (< 15 min). The results demonstrated that the method would have a great value when it is applied in the therapeutic monitoring and pharmacokinetic studies for LND.

Development and validation of ultra-performance liquid chromatographic method with tandem mass spectrometry for determination of lenalidomide in rabbit and human plasma

BACKGROUND

Lenalidomide (LND) is a potent novel thalidomide analog which demonstrated remarkable clinical activity in treatment of multiple myeloma disease via a multiple-pathways mechanism. Validated sensitive method with high throughput is required for the determination of lenalidomide for pharmacokinetics and toxicokinetic studies. Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) is a preeminent analytical tool for rapid biomedical analysis.

RESULTS

A simple, highly sensitive UPLC-MS/MS method was developed and validated for the determination of LND in rabbit and human plasma. After a simple protein precipitation using methanol, LND and carbamazepine (IS) were separated on Acquity UPLC BEH™ C18 column (50 × 2.1 mm, i.d. 1.7 μm, Waters, USA) using a mobile phase consisted of acetonitrile:water:formic acid (65:35:0.1%, v/v/v) pumped at a flow rate of 0.2 mL/min. LND and IS were eluted at 0.71 and 1.92 min, respectively. The mass spectrometric determination was carried out using an electrospray interface operated in the positive mode with multiple reaction monitoring (MRM) mode. The precursor to product ion transitions of m/z 260.1 > 149.0 and m/z 237.0 > 179.0 were used to quantify LND and IS, respectively. The method was linear in the concentration range of 0.23-1000 ng/mL with a limit of quantitation of 0.23 ng/mL. All the validation parameters were in the ranges acceptable by the guidelines of analytical method validation.

CONCLUSION

The proposed UPLC-MS/MS method is simple, rapid and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.