Microdetermination of propofol in plasma by a rapid and sensitive liquid chromatographic method

Rapid detection of propofol in whole blood using an automated on-line molecularly imprinted pretreatment coupled with optical fibre detection

Here we present a validated rapid detection system for propofol, an anaesthetic with a narrow therapeutic window, in whole blood. This method utilises an on-line molecularly imprinted polymer solid-phase extraction, rather than the traditional C18 solid-phase extraction, coupled to fluorescence optical fibre detection. The linearity was assessed from 0.10-15 μg mL(-1) of propofol in whole blood, and the coefficients were greater than 0.995. The absolute recoveries of propofol were 95.81, 97.56 and 97.93% at three different concentrations. The inter-batch precision ranged from 4.3% to 8.1%, and the accuracy value ranged from 102.5% to 104.4%. The developed method was successfully applied to measure propofol concentrations in simulated whole blood samples. The entire analysis procedure lasted only 5 minutes, and the results showed no statistical difference between the new on-line method and a validated high-performance liquid chromatography method. The new on-line method, however, is faster and more convenient for the clinical real-time detection of propofol than previously reported methods.

Headspace-SPME-GC/MS as a simple cleanup tool for sensitive 2,6-diisopropylphenol analysis from lipid emulsions and adaptable to other matrices

Due to increased regulatory requirements, the interaction of active pharmaceutical ingredients with various surfaces and solutions during production and storage is gaining interest in the pharmaceutical research field, in particular with respect to development of new formulations, new packaging material and the evaluation of cleaning processes. Experimental adsorption/absorption studies as well as the study of cleaning processes require sophisticated analytical methods with high sensitivity for the drug of interest. In the case of 2,6-diisopropylphenol - a small lipophilic drug which is typically formulated as lipid emulsion for intravenous injection - a highly sensitive method in the concentration range of μg/l suitable to be applied to a variety of different sample matrices including lipid emulsions is needed. We hereby present a headspace-solid phase microextraction (HS-SPME) approach as a simple cleanup procedure for sensitive 2,6-diisopropylphenol quantification from diverse matrices choosing a lipid emulsion as the most challenging matrix with regard to complexity. By combining the simple and straight forward HS-SPME sample pretreatment with an optimized GC-MS quantification method a robust and sensitive method for 2,6-diisopropylphenol was developed. This method shows excellent sensitivity in the low μg/l concentration range (5-200μg/l), good accuracy (94.8-98.8%) and precision (intraday-precision 0.1-9.2%, inter-day precision 2.0-7.7%). The method can be easily adapted to other, less complex, matrices such as water or swab extracts. Hence, the presented method holds the potential to serve as a single and simple analytical procedure for 2,6-diisopropylphenol analysis in various types of samples such as required in, e.g. adsorption/absorption studies which typically deal with a variety of different surfaces (steel, plastic, glass, etc.) and solutions/matrices including lipid emulsions.

A rapid and simple HPLC method for the analysis of propofol in biological fluids

A selective and sensitive high-performance liquid chromatographic method for the analysis of propofol in biological samples was developed. Propofol and thymol (internal standard) were analysed on a Purospher RP-18 endcapped (75 mmx4 mm, 3 microm) stationary phase using acetonitrile and water (65:35, v/v) as eluents at a flow rate of 0.6 mL/min. The excitation and emission wavelengths were 276 and 310 nm, respectively. Sample treatment consisted of deproteinization by acetonitrile containing the internal standard and direct injection of the supernatant. Mean analytical recovery were 105% (CV 2.0%) at concentrations ranging from 0.05 to 10 mg/L. The quantification limit was 3 ng/mL for a 500 microL sample plasma volume and 5 ng/mL for a 500 microL blood sample. The intra-day and inter-day precisions were lower than 5.5% for three concentrations assessed (0.05, 1.0 and 10.0 mg/L). Considering the column size and the flow rate, the separation was achieved with an analysis time less than 6 min with a reduced consumption of solvent. This rapid HPLC method using a simple treatment procedure is sensitive enough for monitoring propofol in human biological samples.

Microanalysis of propofol in human serum by semi-microcolumn high-performance liquid chromatography with UV detection and solid-phase extraction

OBJECTIVE

To develop a simple analytical method for monitoring the low serum levels of propofol found when administered for the sedation of patients in the intensive care unit (ICU).

METHODS

A high-performance liquid chromatographic method (HPLC) was used with UV detection. Solid-phase extraction (SPE) cartridges and a semi-microcolumn (TSK gel ODS-80Ts, 2.0 mm i.d. x 25 cm, 5 microm) were used to improve sensitivity. Propofol in the eluate obtained from the SPE cartridge was concentrated to about five times the initial concentration.

RESULTS

The sensitivity using the semi-microcolumn was amplified by about three-fold. The assay showed a good linearity with a quantification limit 20 ng/mL. Intra- and inter-assay coefficients of variation were less than 2.2% and 10.0%, respectively. The mean recoveries ranged from 97.6 to 109.5%.

CONCLUSION

The HPLC method described should be useful for measuring the low serum propofol levels found when the drug is used for ICU sedation.

HPLC determination of cisatracurium besylate and propofol mixtures with LC-MS identification of degradation products

A stability-indicating HPLC method was developed to simultaneously determine cisatracurium besylate and propofol in mixtures. The effects of organic modifier, ionic strength and the pH of the mobile phase on resolution and retention were investigated. A baseline separation was achieved on an octadecylsilane column with an isocratic mobile phase of acetonitrile-ammonium formate (pH 5.2; 0.3 M) (50:50, v/v). Cisatracurium and propofol were confirmed by both retention time and mass-to-charge ratio using LC-MS. The degradation products of cistracurium were identified by ESI positive-ion detection as Hofmann elimination and ester hydrolysis products of cisatracurium. There were no propofol degradation products observed. The quantitation of the two drugs was accomplished using UV detection at 280 nm. This method showed linearity for cisatracurium besylate and propofol in the 9-128 and 37-592 micrograms ml-1 ranges, respectively. Accuracy and precision were in the 0.4-1.4 and 0.4-2.9% ranges respectively, for both analytes.