[Source Apportionment of Morphine in Wastewater].

It is a new approach to identify legal or illegal use of morphine through information on municipal wastewater. However, the sources of morphine in wastewater are complex, and distinguishing the contribution of different sources has become a key issue. A total of 262 influent samples from 61 representative wastewater treatment plants in a typical city were collected from October 2022 to March 2023. The concentrations of morphine, codeine, thebaine, papaverine, noscapine, and monoacetylmorphine were analyzed in wastewater and poppy straws. Combined with the proportion of alkaloids in poppy straws, the source analysis of alkaloids in wastewater was analyzed using the ratio method and positive matrix factorization model (PMF). Only five alkaloids were detected in wastewater, and monoacetylmorphine, a metabolite of heroin, was not detected. The concentrations of morphine and codeine were significantly higher than those of noscapine, papaverine, and thebaine. By constructing the ratios of codeine/(morphine + codeine) and noscapine/(noscapine + codeine), the source of poppy straw could be qualitatively distinguished. The PMF results showed that three sources of morphine for medical use, poppy straw, and codeine contributed 44.9%, 43.7%, and 9.4%, respectively. The different sources varied in these months due to the COVID-19 and influenza A outbreaks, in which the use of drugs containing poppy straws and codeine was the main source, whereas the use of morphine analgesics remained relatively stable. Inventory analysis further demonstrated the reliability of the source contributions from the PMF model, and morphine was not abused in this city.

Hollow Fiber Liquid-Phase Microextraction At-Line Coupled to Capillary Electrophoresis for Direct Analysis of Human Body Fluids.

A simple and cheap all-in-one concept for at-line coupling of hollow fiber liquid-phase microextraction (HF-LPME) to commercial capillary electrophoresis (CE) is demonstrated, which enables the direct analysis of complex samples. A disposable microextraction device compatible with injection systems of Agilent CE instruments is proposed, which consists of a short segment of a porous HF attached to a tapered polypropylene holder. The holder maintains a constant position of the HF in a CE vial during extraction and simultaneously guides the injection end of a separation capillary into the HF lumen for automated CE injection and analysis. In a typical analytical procedure, the HF is impregnated with a water-immiscible solvent, its lumen is filled with 5 µL of an aqueous acceptor solution, and the microextraction device is placed in a 2 mL glass CE vial containing 550 µL of a donor solution. The vial is agitated at 750 rpm for 10 min, and the resulting acceptor solution is injected directly from the HF lumen into the commercial CE. No additional manual handling is required, except for the transfer of the CE vial to the CE autosampler. Multiple complex samples can be simultaneously pretreated in a multiple-well plate format, thus significantly reducing the total analysis time. Suitability of the analytical method is demonstrated by the direct determination of model basic drugs (nortriptyline, haloperidol, loperamide, and papaverine) in physiological solutions, urine, and dried blood spot (DBS) samples. Repeatability of the method is better than 12.8% (%RSD), extraction recoveries range between 34 and 76%, and enrichment factors are 37-84. The method is linear in a range of 2 orders of magnitude (R2 ≥ 0.9977) with limits of detection of 0.7-1.55 µg/L. The method has a high potential for the direct analysis of DBS samples since DBS elution and HF-LPME are performed simultaneously during the 10 min agitation. The manual DBS handling is thus reduced to inserting the DBS punch into the CE vial only. Moreover, the universal character of the HF-LPME might extend the applicability of the method to a wide range of analytes/matrices, and combination with other commercial detectors might improve the selectivity/sensitivity of the CE analysis.

Aerodynamic Thermal Breakup Droplet Ionization in Mass Spectrometric Drug Analysis.

Aerodynamic thermal breakup droplet ionization (ATBDI) in mass spectrometric drug analysis is considered. Cocaine, heroin, and the main alkaloids of opium (morphine, codeine, papaverine) were chosen as the test compounds. The principles of ATBDI ionization are discussed. The dependences of the intensities of the peaks of the target compounds on temperature during ATBDI ionization are also considered. In some cases, a comparison of ATBDI ionization with electrospray ionization (ESI) was performed. In addition, a comparison of methods is demonstrated by the analysis of confiscated opium that was provided by the local police department. Five major alkaloids are found in opium: morphine, codeine, thebaine, papaverine, and narcotine.

Developing a miniaturized setup for in-tube simultaneous determination of three alkaloids using electromembrane extraction in combination with ultraviolet spectrophotometry.

Herein, electromembrane extraction was combined with ultraviolet spectrophotometry using a customized manifold for preconcentration and simultaneous determination of morphine, codeine, and papaverine in water and human urine samples. Absorption spectra of the extracts were recorded inside the lumen of the hollow fiber using two fiber optics connected to a miniature spectrophotometer. Partial least squares regression was applied to resolve the overlapped spectra of the analytes. Performance of the model was validated by an independent test set. Central composite design was applied to optimize the extraction parameters. The optimized extraction conditions are as follows; supporting liquid membrane: 2-nitrophenyl octyl ether containing 15% v/v bis(2-ethylhexyl) phosphate, applied voltage: 80 V, donor pH: 3.0, acceptor pH: 1.0, extraction time: 20 min. Finally, the optimized extraction method was validated for determination of the mentioned alkaloids in human urine samples. The method showed good linearity (R2  > 0.995) for all of the mentioned alkaloids. The limits of detection for morphine, codeine, and papaverine in diluted human urine were found to be 0.6, 1.1, and 0.6 ng/mL, respectively with acceptable relative standard deviations. Enrichment factors of 104, 108, and 102 were achieved for morphine, codeine, and papaverine, respectively.

Detection of opium alkaloids in a Cypriot base-ring juglet.

A method has been developed for extracting poppy alkaloids from oily matrices, specifically lipid residues associated with archaeological ceramics. The protocol has been applied to fresh and artificially aged poppyseed oil and to residue from a Late Bronze Age Cypriot juglet in the collections of the British Museum. The juglet is of a type that has been linked with ancient trade in opium due to its poppy-head shape and wide distribution; it is a rare example of an intact vessel with contents sealed inside. Bulk analysis of the residue by GC-EI-MS and pyGC-EI-MS indicated a degraded plant oil and possible presence of papaverine. Analysis of the alkaloid extracts by HPLC-ESI-MS using both triple quadrupole and FTICR mass spectrometers detected the five primary opium alkaloids in fresh poppyseed oil and papaverine in most of the aged samples. Papaverine and thebaine were detected in the juglet residue, providing the first rigorous chemical evidence to support a link between this vessel type and opium, or at least poppies. The association of opium with oil raises new questions about the ancient purpose of the commodities within these vessels, and the low levels (ng g-1) of opiates detected in this unusually well-preserved residue shed doubt on the scope for their detection in more fragmentary ceramic remains (potsherds). Papaverine was found to exhibit challenging carryover behaviour in all the analytical methods used in this study. The phenomenon has not been reported before and should be considered in future analyses of this analyte in all application areas.

Evaluation of hydrophilic interaction liquid chromatography stationary phases for analysis of opium alkaloids.

The separation of a mixture containing five major opium alkaloids, namely morphine, codeine, thebaine, noscapine and papaverine has been investigated in hydrophilic interaction liquid chromatography (HILIC) mode using five different stationary phases: bare silica, zwitterion, aminopropyl, diol and cyanopropyl. In order to propose the appropriate column for separation and purification, retention behaviors of the five natural opioids have been studied on mentioned HILIC stationary phases. The mechanism of separation in diverse HILIC media, based on the formation of water-rich layer on surface of the HILIC stationary phases and the physicochemical properties of opium alkaloids, such as pKa (acidic pK) and the octanol-water distribution coefficient (log Do/w) are discussed. Chromatographic responses including modified limit of detection LODm, signal to noise ratio (S/N)m, and defined modified RSm have considered for suggestion of the suitable column for quantitative/qualitative and preparative purposes. According to the obtained results, diol stationary phase is best suited for analytical chromatography, whereas bare silica and zwitterionic stationary phases are appropriate for preparative applications.

Injections from sub-µL sample volumes in commercial capillary electrophoresis.

A simple sample injection procedure compatible with commercial capillary electrophoresis (CE) instrumentation was developed, which enables handling sample volumes as little as 250nL for analytical applications where sample volume availability is of concern. Single-use micro-sampling inserts were prepared by thermal modification of polypropylene micropipette tips and the inserts were accommodated in standard CE vials in CE autosampler carousel. To ensure direct contact of separation capillary injection end with sample solution and to avoid possible damage to the capillary, a soft compression spring was placed at the bottom of the vial underneath the micro-sampling insert. Injections from sub-µL samples were carried out in conventional as well as in short-end injection mode, were compatible with standard i.d./o.d. (25-100µm/365µm) fused silica capillaries and with various background electrolyte solutions and detection modes. Excellent repeatability of replicate injections from 250nL to 3µL was achieved based on RSD values of quantitative analytical measures (peak heights ≤2.4% and peak areas ≤3.7%) for CE-UV-vis, CE-ESI-MS and CE-contactless conductivity detection of model basic drugs. The achieved RSD values were comparable with those for replicate injections of the drugs from standard CE vials. The reported concept of injections from micro-sampling inserts was further demonstrated useful in evaluation of micro-electromembrane extraction (µ-EME) of model basic drugs. Sub-µL volumes of operational solutions resulted in reduced lengths of µ-EME phases and improved extraction recoveries (66-91%) were achieved.

Evaluation of the efficiency of continuous wavelet transform as processing and preprocessing algorithm for resolution of overlapped signals in univariate and multivariate regression analyses; an application to ternary and quaternary mixtures.

Wavelets have been adapted for a vast number of signal-processing applications due to the amount of information that can be extracted from a signal. In this work, a comparative study on the efficiency of continuous wavelet transform (CWT) as a signal processing tool in univariate regression and a pre-processing tool in multivariate analysis using partial least square (CWT-PLS) was conducted. These were applied to complex spectral signals of ternary and quaternary mixtures. CWT-PLS method succeeded in the simultaneous determination of a quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PAR) and p-aminophenol (PAP, the major impurity of paracetamol). While, the univariate CWT failed to simultaneously determine the quaternary mixture components and was able to determine only PAR and PAP, the ternary mixtures of DRO, CAF, and PAR and CAF, PAR, and PAP. During the calculations of CWT, different wavelet families were tested. The univariate CWT method was validated according to the ICH guidelines. While for the development of the CWT-PLS model a calibration set was prepared by means of an orthogonal experimental design and their absorption spectra were recorded and processed by CWT. The CWT-PLS model was constructed by regression between the wavelet coefficients and concentration matrices and validation was performed by both cross validation and external validation sets. Both methods were successfully applied for determination of the studied drugs in pharmaceutical formulations.

Simultaneous quantification of paracetamol, acetylsalicylic acid and papaverine with a validated HPLC method.

Combined drug products have the advantages of better patient compliance and possible synergic effects. The simultaneous application of several active ingredients at a time is therefore frequently chosen. However, the quantitative analysis of such medicines can be challenging. The aim of this study is to provide a validated method for the investigation of a multidose packed oral powder that contained acetylsalicylic acid, paracetamol and papaverine-HCl. Reversed-phase high-pressure liquid chromatography was used. The Agilent Zorbax SB-C18 column was found to be the most suitable of the three different stationary phases tested for the separation of the components of this sample. The key parameters in the method development (apart from the nature of the column) were the pH of the aqueous phase (set to 3.4) and the ratio of the organic (acetonitrile) and the aqueous (25 mM phosphate buffer) phases, which was varied from 7:93 (v/v) to 25:75 (v/v) in a linear gradient, preceded by an initial hold. The method was validated: linearity, precision (repeatability and intermediate precision), accuracy, specificity and robustness were all tested, and the results met the ICH guidelines.

Determination of residues of acetaminophen, caffeine, and drotaverine hydrochloride on swabs collected from pharmaceutical manufacturing equipment using HPLC in support of cleaning validation.

An HPLC method was developed for the simultaneous determination of residues of acetaminophen (paracetamol, PA), caffeine (CA), and drotaverine HCl (DH) on swabs collected from pharmaceutical manufacturing equipment surfaces. The challenge in cleaning validation is to develop analytical methods that are sensitive enough to detect traces of the active compounds remaining on the surface of pharmaceutical manufacturing equipment after cleaning. Chromatography was performed in the isocratic mode on a Hypersil C18 BDS column using the mobile phase 0.02 M tetrabutylammonium bisulfate-methanol (100 + 45, v/v) at 50°C with UV detection at 210 nm. The method was tested for specificity, linearity, LOD, LOQ, accuracy, and precision for determination of traces of the above-mentioned drugs. The time required for a single analysis was 12 min. The response was linear in the ranges of 6.900-52.100, 1.040-7.800, and 0.694-5.210 µg/mL for PA, CA, and DH, respectively.

Physicochemical stability study of a new Trimix formulation for treatment of erectile dysfunction.

Currently, severe erectile dysfunction can be treated by intracavernous injections of solutions containing three active ingredients: prostaglandin E1 (PGE1), papaverine and urapidil. Very few data exist on this mixture where phentolamine has been replaced by Urapidil because Phentolamine is not used for this indication in France. The aim of our study was to assess the stability of this formulation and to extend its expiration to permit preparation of batches. Three batches of the preparation containing 15µg/mL PGE1, 15mg/mL of papaverine and 2mg/mL urapidil were made aseptically and then packed in polypropylene syringes stored at 4°C. The physico-chemical stability has been tested as follows: HPLC stability-indicating method, visual observation, measurement of pH and osmolarity. We found that the limiting factor was PGE1 and we exceeded the threshold of 10% loss after 55 days. Replacement of Urapidil by Phentolamine seems to have a slight detrimental effect on stability. Nevertheless, these results allow us to consider the advance preparation of this formulation and provide quality treatment to these patients by avoiding too frequent visits to the hospital.

Use of potentiometric detection in (ultra) high performance liquid chromatography and modelling with adsorption/desorption binding kinetics.

Observation of a potentiometric sensor's response behaviour after injection in flow injection analysis at different concentrations allowed studying "on" and "off" kinetics of the analyte's adsorption/diffusion behaviour. The alkaloid metergoline was mostly used as an example. k(on) and k(off) rate constant values were measured, and the association constant K(ass), and ΔG values of the analyte-surface interaction were calculated with an adsorption-based model which proved to be fully applicable. k(on) increased by decreasing the sensor dimensions, while koff was unaffected by miniaturization. Increasing acetonitrile concentrations in the running buffer increased k(off), while k(on) was unaffected. The experimentally determined ΔG values of the analyte-surface interaction showed a linear relation to the response of the sensor, in mV. This knowledge was applied to optimize the potentiometric detection of plant alkaloids in (U)HPLC. Sub-micromolar detection limits were obtained with the potentiometric detector/(U)HPLC combination. This is the first time that the response rates and the response itself can be modelled accurately for coated wire potentiometric sensors, and it is the first application of a potentiometric detector in UPLC.

[Simultaneous determination of 5 kinds of alkaloids in Kechuanning tablets by SPE-UPLC under different UV-vis wavelength].

The paper is to establish a method for simultaneous determination of 5 kinds of alkaloids in ephedra and poppy which are in Kechuanning tablets. Solid-phase extraction (SPE) was adopted in pretreatment, and a UPLC method with 2 different wavelengths had been developed: 210 nm for the detection of morphine, codeine phosphate, ephedrine hydrochloride and pseudoephedrine hydrochloride, and 251 nm for papaverine hydrochloride. The column used was Acquity UPLC BEH C18 (100 mm x 2.1 mm ID, 1.7 microm) with linear gradient elution using acetonitrile and 0.1% phosphoric acid. The flow rate was 0.4 mL.min-1, and the column temperature was 30 degrees C. The linear response range was 0.375 0 - 12.50 microg.mL-1 for morphine, 0.064 32 - 2.144 microg.mL-1 for codeine phosphate, 0.030 06 - 1.002 microg.mL-1 for papaverine hydrochloride, 1.126 - 37.52 microg.mL-1 for ephedrine hydrochloride, 0.287 8 - 9.592 microg.mL-1 for pseudoephedrine hydrochloride (r = 0.999 7). The average recoveries of these compounds were 99.26%, 100.6%, 95.29%, 100.1% and 97.48%, respectively. This is a more reasonable and credible method of quality control for Kechuanning tablets.

Validation and application of chemometrics-assisted spectrophotometry and liquid chromatography for simultaneous determination of two ternary mixtures containing drotaverine hydrochloride.

Three methods were developed for the determination of two ternary mixtures containing drotaverine hydrochloride (DR) with caffeine and paracetamol (mixture 1) and DR with metronidazole and diloxanide furoate (mixture 2). The first method depends on HPLC separation on an RP C18 column at ambient temperature with the mobile phase methanol-water, pH 3.1 (50 + 50, v/v) and UV detection at 213 nm for mixture 1, and the mobile phase acetonitrile-25 mM potassium dihydrogen phosphate, pH 4.6 (55 + 45, v/v) with UV detection at 235 nm for mixture 2. The other two chemometric methods applied were partial least squares (PLS-1) and principal component regression (PCR). These approaches were successfully applied to quantify the five drugs in two ternary mixtures using information included in the UV absorption spectra of appropriate solutions in the wavelength range of 210-300 nm with 1 nm intervals. Calibration of PCR and PLS-1 models was evaluated by internal validation (prediction of compounds in its own designed training set of calibration), by cross-validation (obtaining statistical parameters that show the efficiency for a calibration fit model), and by external validation (using laboratory-prepared mixtures and pharmaceutical preparations). The proposed methods were successfully applied for the determination of the two ternary combinations in laboratory-prepared mixtures and commercial tablets; the results of PLS-1 and PCR methods were compared with the HPLC method, and a good agreement was found.

pH Gradient as a tool for the separation of ionizable analytes in reversed-phase high-performance chromatography.

The aim of this work was to propose a general scheme of optimizing separation of ionizable analytes and to determine conditions of maximal peak compression in pH-gradient reversed-phase high-performance liquid chromatography (RP HPLC). The approximated explicit equation of the linear pH gradient has been developed. It allows predicting retention times for a given organic modifier content, initial value of pH, and the start and steepness of the pH gradient. Also the formula for calculating maximal peak compression is provided. The developed theory was compared with experimental data on the example of a weak acid (ketoprofen) and a weak base (papaverine). Five parameters characterizing analyte retention (log k(w) and S of the ionized and nonionized forms along with pK(a,chrom)) were determined in a series of isocratic experiments carried out at different pH values and with different methanol contents in the eluent. Next, a series of pH gradients of different pH-gradient steepness and of different pH-gradient starting time has been obtained and used to test the validity of our theoretical approach. The conditions of maximal peak width compression have been found. The derived theory was proved to be in a good agreement with the experimental data. The pH-gradient method led to peak compression of up to 0.2, and minimized peak tailing was obtained for the tested analytes. Since the majority of analytical separations are done in an isocratic mode we proposed a means to transfer an isocratic method to a pH-gradient method.

Cathodic adsorptive stripping voltammetry of drotaverine hydrochloride and its determination in tablets and human urine by differential pulse voltammetry.

The stripping voltammetric behaviour of drotaverine hydrochloride (DvCl) was studied using a hanging mercury drop electrode (HMDE). The adsorptive stripping response has been evaluated with respect to pH, accumulation time, accumulation potential, scan rate and other variables. Differential pulse DP mode; over the potential range -400 to -1200 mV, is used in the presence of 0.04 M Britton-Robinson buffer pH 2. Cyclic voltammetric study indicates that the reduction process is irreversible and controlled by adsorption. The response of DP technique is linear over the concentration range 21.70-257.34 ng/ml. Limit of detection and limit of quantification were 3.15 and 10.50 ng/ml, respectively. The proposed method was successfully applied for the determination of the drug in commercial tablets and spiked human urine samples.

Determination of diclofenac sodium and papaverine hydrochloride in tablets by HPLC method.

A HPLC method for simultaneous determination of diclofenac sodium and papaverine hydrochloride in tablets was developed and validated. The determination was performed with a Zorbax SB-C18 column, mobile phase: methanol-water (60:40, v/v), flow rate: 1 mL min(-1) and UV detection at 278 nm.

[Absorption of papaverine, laudanosine and cepharanthine across human intestine by using human Caco-2 cells monolayers model].

Absorption of papaverine (PAP), laudanosine (LAU) and cepharanthine (CEP) as some chemical constituents of traditional Chinese medicines in human intestine were studied. By using Caco-2 (the human colonic adenocarcinoma cell lines) cell monolayers as an intestinal epithelial cell model, the permeability of PAP, LAU and CEP were studied from apical side (AP side) to basolateral side (BL side) or from BL side to AP side. The three alkaloids were measured by reversed-phase high-performance liquid chromatography coupled with UV detector. Transport parameters and apparent permeability coefficients (Papp) were then calculated and compared with those of propranolol as a control substance of high permeability and atenolol as a control substance of poor permeability. The Papp values of PAP, LAU and CEP were (3.524+/-0.223) x 10(-5), (2.821+/-0.050) x 10(-5) and (6.524+/-0.052) x 10(-5) cm s(-1) from AP side to BL side, and (5.095+/-0.508) x 10(-5), (2.646+/-0.146) x 10(-5) and (5.495+/-0.036) x 10(-5) cm s(-1) from BL side to AP side, respectively. Their Papp values were identical with those of propranolol, which is a transcellular transport marker. On the other hand, the efflux transport of PAP was 1.45 times higher than its influx transport with 0.69 rate of P(app A-->B)/P(app B-->A). But P(app A-->B)/P(app B-->A) values of LAU and CEP were 1.07 and 1.19, respectively, which suggested that the efflux transport have not been involved in their absorbed mechanism in Caco-2 cells monolayers. There is a good correlation between the Papp value and apparent distribution coefficient (Log D) at pH 7.35 for the three alkaloids. PAP, LAU and CEP can be absorbed across intestinal epithelial cells, and they are completely absorbed compounds. PAP may have been involved in efflux mechanism in Caco-2 cells monolayers model from the basolateral-to-apical direction. The O/W (oil/water) partition coefficient plays key role in their transmembrane permeation.

Simultaneous determination of nifuroxazide and drotaverine hydrochloride in pharmaceutical preparations by bivariate and multivariate spectral analysis.

The quantitative predictive abilities of the new and simple bivariate spectrophotometric method are compared with the results obtained by the use of multivariate calibration methods [the classical least squares (CLS), principle component regression (PCR) and partial least squares (PLS)], using the information contained in the absorption spectra of the appropriate solutions. Mixtures of the two drugs Nifuroxazide (NIF) and Drotaverine hydrochloride (DRO) were resolved by application of the bivariate method. The different chemometric approaches were applied also with previous optimization of the calibration matrix, as they are useful in simultaneous inclusion of many spectral wavelengths. The results found by application of the bivariate, CLS, PCR and PLS methods for the simultaneous determinations of mixtures of both components containing 2-12microgml(-1) of NIF and 2-8microgml(-1) of DRO are reported. Both approaches were satisfactorily applied to the simultaneous determination of NIF and DRO in pure form and in pharmaceutical formulation. The results were in accordance with those given by the EVA Pharma reference spectrophotometric method.

Separation and determination of five major opium alkaloids with mixed mode of hydrophilic/cation-exchange monolith by pressurized capillary electrochromatography.

A method for the separation and determination of five major opium alkaloids (narcotine, papaverine, thebaine, codeine, and morphine) in pericarpium papaveris by pressurized CEC (pCEC) with monolithic column has been developed. Under the optimum condition, linear calibration ranges of narcotine, papaverine, thebaine, codeine, and morphine were obtained as 2-85, 2-85, 5-75, 10-65, and 10-65 microg/mL, respectively. LODs of these analytes were 1.5-6.0 microg/mL. The RSD (n=7) of the migration time and peak area were 1.94-5.24 and 4.05-8.21%, respectively. The proposed method was successfully applied to the analysis of pericarpium papaveris samples. Average recoveries of 79.0-95.9% at different fortified levels of alkaloids were achieved with RSD less than 4.6%. Meanwhile, the mechanism of the separation of the alkaloids on the monolithic column was also discussed. The result showed that the separation of alkaloids was mainly based on the mixed mode of hydrophilic interaction (HI) and cation exchange.