Extraction of clenbuterol from urine using hydroxylated poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith microextraction followed by high-performance liquid chromatography determination

Development and Validation of a Stability Indicating LC-MS/MS Method for the Determination of Clenbuterol HCl

Clenbuterol hydrochloride (CLT), β₂ adrenergic agonist is used as a bronchodilator in the therapeutic treatment of asthma. It is important to know the stability behaviour of the drug in different degradation conditions as per ICH Q1A (R2) guidelines for safety and efficacy purpose. The main objective of the study is to develop and validate stability indicating LC-MS/MS method for the determination of Clenbuterol HCl. The separation was achieved using Phenomenex Gemini NX C18 (250*4.6 mm, 5 μ) column and the mobile phase consisting of ammonium acetate buffer (5 mM), 0.15% triethylamine (TEA), pH 7.5 with acetic acid: methanol (70:30, v/v) at flow rate 1 ml/min. The detection was done using PDA detector at 245 nm. The validation was performed as per ICH Q2 (R1) guideline. The drug was subjected to stress degradation conditions as per ICH Q1A (R2) guidelines. The significant degradation was observed in acidic (8.78%) and sunlight (liquid) (9%) condition while no degradation was observed in neutral, basic, oxidation and thermal condition. The drug and its degradation products were characterized using LC-MS/MS and the proposed degradation mechanism was communicated. The developed method was found to be stability-indicating, simple, specific, selective, sensitive, linear, accurate, robust and precise and used as a routine analysis in quality control laboratory.

Clenbuterol Hydrochloride

Clenbuterol (Broncodil and trade) is a direct-acting sympathomimetic agent with mainly beta-adrenergic activity and a selective action on β2 receptors (a β2 agonist). It has properties similar to those of salbutamol. It is used as a bronchodilator in the management of reversible airways obstruction, as in asthma and in certain patients with chronic obstructive pulmonary disease. The uses, applications, and the synthetic pathways of this drug are outlined. Physical characteristics including: ionization constant, solubility, X-ray powder diffraction pattern, thermal methods of analysis, UV spectrum, IR spectrum, mass spectrum are all produced. This profile also includes the monograph of British Pharmacopoeia, together with several reported analytical methods including spectrophotometric, electrochemical, chromatographic, immunochemical methods, and capillary electrophoretic methods. The stability, the pharmacokinetic behavior, and the pharmacology of the drug are also provided.

Methacrylate Polymer Monoliths for Separation Applications

This review summarizes the development of methacrylate-based polymer monoliths for separation science applications. An introduction to monoliths is presented, followed by the preparation methods and characteristics specific to methacrylate monoliths. Both traditional chemical based syntheses and emerging additive manufacturing methods are presented along with an analysis of the different types of functional groups, which have been utilized with methacrylate monoliths. The role of methacrylate based porous materials in separation science in industrially important chemical and biological separations are discussed, with particular attention given to the most recent developments and challenges associated with these materials. While these monoliths have been shown to be useful for a wide variety of applications, there is still scope for exerting better control over the porous architectures and chemistries obtained from the different fabrication routes. Conclusions regarding this previous work are drawn and an outlook towards future challenges and potential developments in this vibrant research area are presented. Discussed in particular are the potential of additive manufacturing for the preparation of monolithic structures with pre-defined multi-scale porous morphologies and for the optimization of surface reactive chemistries.

Sensitive voltammetric sensor based on isopropanol-Nafion-PSS-GR nanocomposite modified glassy carbon electrode for determination of clenbuterol in pork

In the present study, poly(sodium 4-styrenesulfonate) (PSS) functionalized graphene (GR) was synthesised via a simple one-step chemical reduction of exfoliated graphite oxides in the presence of PSS. Characterisation of as-made nanocomposite using Fourier transform infrared spectroscopy (FT-IR) and ultraviolet and visible spectroscopy (UV-vis) clearly demonstrate the successful attachment of PSS to graphene sheets. A novel clenbuterol (CLB) electrochemical sensor was fabricated based on isopropanol-Nafion-PSS-GR composite film modified glassy carbon electrode. In the Britton-Robinson buffer (pH 1.2), the sensor exhibited superior electrocatalytic activity towards the oxidation of CLB. Applying linear sweep voltammetry, a good linear relationship of the oxidation peak current with respect to concentrations of CLB cross the range of 7.5 × 10(-8)-2.5 × 10(-5)mol L(-1) and a detection limit of 2.2 × 10(-8) mol L(-1) were achieved. The proposed method was successfully applied for the determination of CLB in pork.

Recent advances in column switching sample preparation in bioanalysis

Column switching techniques, using two or more stationary phase columns, are useful for trace enrichment and online automated sample preparation. Target fractions from the first column are transferred online to a second column with different properties for further separation. Column switching techniques can be used to determine the analytes in a complex matrix by direct sample injection or by simple sample treatment. Online column switching sample preparation is usually performed in combination with HPLC or capillary electrophoresis. SPE or turbulent flow chromatography using a cartridge column and in-tube solid-phase microextraction using a capillary column have been developed for convenient column switching sample preparation. Furthermore, various micro-/nano-sample preparation devices using new polymer-coating materials have been developed to improve extraction efficiency. This review describes current developments and future trends in novel column switching sample preparation in bioanalysis, focusing on innovative column switching techniques using new extraction devices and materials.

Analytical methods for the detection of clenbuterol

Clenbuterol is therapeutically used for the treatment of pulmonary diseases such as bronchial asthma or for tocolytic reasons. In cattle feeding as well as in sports it is illicitly misused due to its anabolic properties to promote muscle growth. Sample preparation procedures and analytical techniques used for the detection of clenbuterol are manifold and vary with the objectives of the investigation. Methods for its detection in biological specimens, drug preparations, the environment, food and feed products are reported. They are mainly based on immunochemical, chromatographic and mass spectrometric techniques, or on capillary electrophoresis. Sample preparation primarily includes liquid-liquid extraction and solid-phase extraction. Depending on the aim of the method clenbuterol can be determined in single- or multi-analyte methods. In biological and environmental samples concentrations are generally low due to the potency of the drug. Thus, highly sensitive procedures are required for expedient analyses.