Solubility, pH-Solubility Profile, pH-Rate Profile, and Kinetic Stability of the Tyrosine Kinase Inhibitor, Alectinib

Alectinib HCl (ALBHCl) is a tyrosine kinase inhibitor used for non-small cell lung carcinoma (NSCLC). The aim of this study is to unlock some of the physicochemical properties of ALBHCL that serve as a database for any future studies. A solubility study of ALBHCL was performed in different solvents. Also, photostability was tested in the solution and solid states, and the order of reaction and rate constant were calculated. In addition to the pH solubility relation, the pH-rate relation at different temperatures was also studied, and the profiles were constructed. A solubility study was also performed in different media for the purpose of optimizing suitable sink conditions for the in vitro dissolution testing of solid dosage forms. Solubility tests in multiple solvents and pH conditions revealed that the highest solubility was in DMSO, methanol, and chloroform, with acidic media yielding the maximum solubility but degrading at rather low pH levels. ALBHCL proved unstable at high temperatures and under light exposure, with varying stability across different pH levels. The optimal dissolution media for in vitro oral dosage form evaluation were determined, achieving sink conditions at pH levels of 6.8 and 4.5 with specific additives. This study enhances the existing database on ALBHCL's physicochemical properties, emphasizing the importance of pH optimization in pharmaceutical processes and providing valuable insights into its pharmaceutical application.

Determination of alectinib and its active metabolite in plasma by pipette-tip solid-phase extraction using porous polydopamine graphene oxide adsorbent coupled with high-performance liquid chromatography-ultraviolet detection

Alectinib is known as an effective targeted drug, which has excellent therapeutic effect on non-small cell lung cancer and can significantly prolong the survival of patients. Therapeutic drug monitoring is necessary due to the photo-instability of alectinib and the individual differences in patients. In this work, a porous polydopamine graphene oxide composite (PDAG) was prepared by a simple surface modification method. A PDAG-based pipette-tip solid-phase extraction (PT-SPE) coupled with HPLC-UV detection was proposed for the separation and detection of alectinib and its active metabolite M4 in plasma. The method was methodologically validated and showed good linearity in the range of 50-5000 ng mL-1 (R2 > 0.9995). The limit of detection (LOD) was 4.8 ng mL-1 and 3.9 ng mL-1 for alectinib and M4, respectively, and the limit of quantitation (LOQ) was 16.1 ng mL-1 and 13.1 ng mL-1, respectively. The intra-day and inter-day precision expressed by coefficient of variation was less than 4.8 %. The recovery of this method ranged from 84.9 % to 103.5 % with a standard deviation of less than 4.3 %. In conclusion, the established method is accurate, stable and inexpensive, and can be used to monitor the levels of alectinib and M4 in plasma, which provide technical and data support for exploring optimal individualized remedial dosing regimens.

Development of Novel Microwell-Based Spectrofluorimetry and High-Performance Liquid Chromatography with Fluorescence Detection Methods and High Throughput for Quantitation of Alectinib in Bulk Powder and Urine Samples

Background and Objectives: This study presents the development and validation of the 96-microwell-based spectrofluorimetric (MW-SFL) and high performance liquid chromatography (HPLC) with fluorescence detection (HPLC-FD) methods for the quantitation of alectinib (ALC) in its bulk powder form and in urine samples. Materials and Methods: The MW-SFL was based on the enhancement of the native fluorescence of ALC by the formation of micelles with the surfactant cremophor RH 40 (Cr RH 40) in aqueous media. The MW-SFL was executed in a 96-microwell plate and the relative fluorescence intensity (RFI) was recorded by utilizing a fluorescence plate reader at 450 nm after excitation at 280 nm. The HPLC-FD involved the chromatographic separation of ALC and ponatinib (PTB), as an internal standard (IS), on a C18 column and a mobile phase composed of methanol:potassium dihydrogen phosphate pH 7 (80:20, v/v) at a flow rate of 2 mL min–1. The eluted ALC and PTB were detected by utilizing a fluorescence detector set at 365 nm for excitation and 450 nm for emission. Results: Validation of the MW-SFL and HPLC-FD analytical methods was carried out in accordance with the recommendations issued by the International Council for Harmonization (ICH) for the process of validating analytical procedures. Both methods were efficaciously applied for ALC quantitation in its bulk form as well as in spiked urine; the mean recovery values were ≥86.90 and 95.45% for the MW-SFL and HPLC-FD methods, respectively. Conclusions: Both methodologies are valuable for routine use in quality control (QC) laboratories for determination of ALC in pure powder form and in human urine samples.

Honeycomb resin-based spin-column solid-phase extraction for efficient determination of alectinib and its metabolite in human urine

Alectinib and its metabolite, M4, have demonstrated a satisfactory clinical therapeutic effect in the treatment of anaplastic lymphoma kinase-positive advanced non-small-cell lung cancer. Due to individual differences among patients, therapeutic drug monitoring (TDM) is critical for guaranteeing appropriate clinical drug use. To realize TDM for alectinib and its metabolite, M4, a honeycomb phenol-formaldehyde resin (PFR) with excellent hydrophilic properties, abundant adsorption force, and a stable porous structure was synthesized by modifying the porogens F127 and P123. The prepared PFR was employed as an adsorbent in a simple and efficient spin-column solid-phase extraction (SPE) process. A rapid method for detecting alectinib and its metabolite M4 in urine was thereby established. The established method showed a linear range of 0.0200 μg mL^-1-5.00 μg mL^-1 and the recovery range of 98.8-103% for spiked urine samples, with relative standard deviations of ≤ 4.87% (n = 3). Our results proved the practicability of the proposed honeycomb-PFR spin-column SPE method in TDM for alectinib and its metabolite, M4.

Simple HPLC method for simultaneous quantification of nicotine and cotinine levels in rat plasma after exposure to two different tobacco products

Purpose

Development and validation of a selective analytical method to accurately and precisely quantify nicotine and cotinine levels in rat's plasma after exposure to tobacco cigarettes and tobacco water-pipe.

Methods

An easy HPLC-Photodiode-Array Detection (PDA) method was developed and validated for simultaneous determination of nicotine and cotinine levels in plasma of 15 rats (10 rats after tobacco products exposure and 5 control rats). Nicotine and cotinine were extracted in one step from plasma using acetonitrile and concentrated to lowest volume using nitrogen stream.

Results

The developed method offered a rapid analysis time of 14 min with single step of analytes extraction from rat's plasma with recovery percentage range between 93 and 95% and excellent linearity with correlation factor more than 0.994 with analytical range between 50 and 1000 ng mL−1 and LOD of 25 ng mL−1 and 23 ng mL−1 for nicotine and cotinine, respectively. The analysis of rat's plasma after 28 days of exposure to tobacco cigarettes and tobacco water-pipe revealed that the average concentrations of 376 ng mL−1 for cotinine and 223 ng mL−1 for nicotine were obtained after tobacco cigarettes exposure, and 220 ng mL−1 for cotinine and 192 ng mL−1 for nicotine after tobacco water-pipe exposure.

Conclusion

Higher nicotine and cotinine levels were found in plasma after tobacco cigarettes exposure than water-pipe exposure which may have potential undesirable effects on passive smokers in both cases.