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Drug-drug interactions may amplify or diminish their intended effects, or even produce entirely new effects. Multicomponent mixture HPLC analysis offers a thorough and effective method for comprehending the makeup and behavior of complicated materials, advancing research and development across a range of scientific and industrial domains. A novel experimental design-assisted HPLC methodology for the concurrent investigation of the drug-drug interaction of pholcodine, ephedrine, and guaifenesin in biological fluids has been established. Rather than the routine methodology, the application of the factorial design-HPLC method offers a powerful and efficient tool for the analysis of these compounds. Both mixed and full factorial designs were employed to assess the impact of variable factors on chromatographic results. Utilizing an isocratic elution mode on a C18 column, the chromatographic separation was carried out. 15% Methanol, 5% acetonitrile, and 80% phosphate buffer with 0.1%(v/v) triethylamine set to pH 3 make up the mobile phase flowing at rate 1.0 mL/min. The calibration curves of the drugs show excellent linearity over a concentration ranges: 0.20–13.0 µg/mL for PHO, 0.50–20.0 µg/mL for EPH and 0.70–20.0 µg/mL for GUA with LOQ values of 0.18, 0.38 and 0.50. The fast separation and quantitation in less than 6 min is an advantage. Also, the method includes a robust sample preparation protocol for the analysis of complex biological samples, ensuring high selectivity and precision. The ease, speed and cost-effectiveness of the method are ideal for supporting in vitro studies, including drug-drug interaction investigations, especially in bioanalytical labs. [ABSTRACT FROM AUTHOR]

Abstract Drug-drug interactions may amplify or diminish their intended effects, or even produce entirely new effects. Multicomponent mixture HPLC analysis offers a thorough and effective method for comprehending the makeup and behavior of complicated materials, advancing research and development across a range of scientific and industrial domains. A novel experimental design-assisted HPLC methodology for the concurrent investigation of the drug-drug interaction of pholcodine, ephedrine, and guaifenesin in biological fluids has been established. Rather than the routine methodology, the application of the factorial design-HPLC method offers a powerful and efficient tool for the analysis of these compounds. Both mixed and full factorial designs were employed to assess the impact of variable factors on chromatographic results. Utilizing an isocratic elution mode on a C18 column, the chromatographic separation was carried out. 15% Methanol, 5% acetonitrile, and 80% phosphate buffer with 0.1%(v/v) triethylamine set to pH 3 make up the mobile phase flowing at rate 1.0 mL/min. The calibration curves of the drugs show excellent linearity over a concentration ranges: 0.20–13.0 µg/mL for PHO, 0.50–20.0 µg/mL for EPH and 0.70–20.0 µg/mL for GUA with LOQ values of 0.18, 0.38 and 0.50. The fast separation and quantitation in less than 6 min is an advantage. Also, the method includes a robust sample preparation protocol for the analysis of complex biological samples, ensuring high selectivity and precision. The ease, speed and cost-effectiveness of the method are ideal for supporting in vitro studies, including drug-drug interaction investigations, especially in bioanalytical labs.

A validated technique has been developed for the sequential determination of pholcodine, paracetamol, and pseudoephedrine. This method allows for their separation either in different ratios within a ternary mixture or in their fixed-dose combination (FDC) using HPLC. The chromatographic conditions involved the utilization of an X-select C18 column (5µ, 4.6 × 150 mm) and a mobile phase consisting of 0.05 M KH2PO4: Methanol (75:25, v/v), with orthophosphoric acid added to adjust the pH to 2.6. The separation was conducted at a 1.2 ml/min flow rate, while a UV detector was set at a wavelength of 206 nm to monitor the process. The three drugs were successfully eluted with retention times of 0.8, 1.9, and 3.0 min for pholcodine, paracetamol, and pseudoephedrine respectively providing fast analysis times.The method exhibited linearity for pholcodine, paracetamol, and pseudoephedrine over concentration ranges of 12–200 µg/ml, 5–100 µg/ml, and 30–200 µg/ml, respectively. It was accurate, reliable, and precise (RSD < 2 %). This proposed methodology was effectively implemented to quantify the concentration of pholcodine, pseudoephedrine, and paracetamol in freshly prepared mixtures and pharmaceutical dosage forms. Furthermore, the method's environmental impact was assessed using five different tools, demonstrating low hazard levels to the environment, and promoting its environmental friendliness compared to the reported method.

Abstract Pholcodine, an anti-tussive medication widely used as an over-the-counter, OTC drug, has recently faced restrictions in several countries. This paper presents a sensitive electrochemical approach for pholcodine detection. The electrochemical method involved fabricating a graphene nanoplatelets electrode, incorporating polythiophene nanospheres polymer to promote electron transfer and increase the activated surface area. Characterization of the fabricated electrode was performed using transmission electron microscopy, ATR-Fourier-transform infrared spectroscopy, X-ray crystallography, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The electrochemical behavior of pholcodine with the fabricated electrode was investigated using cyclic voltammetry, chronoamperometry, square wave voltammetry (SWV), and differential pulse voltammetry (DPV). The developed electrode led to a linear response for pholcodine ranging from 10 to 45 mg/L with detection limits of 1.41 and 1.51 mg/mL for SWV and DPV, respectively and quantification limits of 4.27 and 4.57 mg/L for SWV and DPV, respectively. The proposed method has accurately recovered pholcodine in spiked serum samples with a recovery percentage ranging from 1.2 to 2.9%. The optimized method is found to be accurate, precise, and robust by applying validation parameters provided by International Council for Harmonization. Two green metrics were computed to assess the method’s greenness, the findings showed that the developed method is environmentally friendly with minimum sample preparation steps.

A spectrophotometric platform based on two smart techniques namely Double Divisor ratio difference spectra spectrophotometry (DDRD) and Derivative ratio amplitude difference method (DR-AD) was applied and validated. These techniques were used for determining and resolving the overlapped spectra of the 3 drugs paracetamol (PAR), pseudoephedrine (PSE) and pholcodine (PHO) in their ternary mixture. DDRD is a successive technique while DR-AD is a progressive one. In DDRD, the mixtures' spectrum underwent division by a double divisor, and then the ratio difference method was applied. For DR-AD, consequent steps were performed to resolve each drug stepwise. DR-AD technique included division using a single divisor. The linearity ranges encompassed 5-25, 100-800 and 5-50 µg/mL for PAR, PSE and PHO, respectively. These methods were conducted according to ICH guidelines to ascertain accuracy, precision, and specificity. The analysis involved varied concentrations of drug mixtures and a pharmaceutical product. Statistical evaluation revealed no notable distinction between the suggested methodologies and those previously documented. Additionally, adherence to green analytical chemistry principles was demonstrated, establishing them as environmentally friendly analytical approaches. [ABSTRACT FROM AUTHOR]

Despite the purported link between pholcodine and neuromuscular blocking agent allergy, screening for prior pholcodine use offers no practical benefit to patients, and anaesthetists should continue to use a neuromuscular blocking agent where this is clinically indicated. [ABSTRACT FROM AUTHOR]

Guaifenesin and pholcodine are frequently co‐formulated in certain dosage forms. A new fast first derivative synchronous spectrofluorometric method has been used for their simultaneous analysis in mixtures. Here, first derivative synchronous spectrofluorometry enabled the successful simultaneous estimation of guaifenesin at 283 nm and pholcodine at 275 nm using a wavelength difference (Δλ) of 40 nm. The method was fully validated following International Council of Harmonization guidelines. For guaifenesin and pholcodine, linearity was determined within the corresponding ranges of 0.05–0.30 and 0.10–6.0 μg/ml. The two drugs were effectively analyzed using the developed approach in their respective formulations, and the results showed good agreement with those attained using reference methods. The method demonstrated excellent sensitivity, with detection limits down to 0.007 and 0.030 μg/ml and quantitation limits of 0.020 and 0.010 μg/ml for guaifenesin and pholcodine, respectively. Therefore, the procedure was successful in determining these drugs simultaneously in vitro in spiked plasma samples and syrup dosage form. The developed methodology also offered an environmentally friendly advantage by utilizing water as the optimal diluting solvent throughout the whole work. Different greenness approaches were investigated to ensure the method's ecofriendly properties. [ABSTRACT FROM AUTHOR]

Abstract Pholcodine and guaiacol are widely used together in pharmaceutical syrups for cough treatment. On the other hand, the Ultra Performance Liquid Chromatographic technique is characterized by having the power of increasing chromatographic efficiency and decreasing run time compared to the traditional High Performance Liquid Chromatographic one. In this work, this power was exploited for the simultaneous determination of pholcodine, guaiacol along with three guaiacol impurities, namely; guaiacol impurity A, guaiacol impurity B, and guaiacol impurity E. Good separation was achieved by employing Agilent Zorbax C8 column (50 × 2.1 mm) as the stationary phase, and acetonitrile: phosphate buffer pH 3.5 (40: 60, by volume) as a mobile phase. The proposed method was validated as per International Council for Harmonisation guidelines. Linear relationships, at ranges of 50–1000 µg mL−1 for pholcodine and 5–100 µg mL−1 for guaiacol and the three related impurities, were established. Finally, the proposed method was applied for pholcodine and guaiacol determination in Coughpent® syrup and compared favorably to the reported one.

Neuromuscular blocking agents (NMBAs) are among the leading cause of perioperative anaphylaxis, and most of these reactions are IgE mediated. Allergic sensitisation induced by environmental exposure to other quaternary ammonium-containing compounds, such as pholcodine, has been suggested. The aim of this study was to assess the relationship between pholcodine exposure and NMBA-related anaphylaxis. ALPHO was a multicentre case-control study, comparing pholcodine exposure within a year before anaesthesia between patients with NMBA-related perioperative anaphylaxis (cases) and control patients with uneventful anaesthesia in France. Each case was matched to two controls by age, sex, type of NMBA, geographic area, and season. Pholcodine exposure was assessed by a self-administered questionnaire and pharmaceutical history retrieved from pharmacy records. The diagnostic values of anti-pholcodine and anti-quaternary ammonium specific IgE (sIgE) were also evaluated. Overall, 167 cases were matched with 334 controls. NMBA-related anaphylaxis was significantly associated with pholcodine consumption (odds ratio 4.2; 95% confidence interval 2.3–7.0) and occupational exposure to quaternary ammonium compounds (odds ratio 6.1; 95% confidence interval 2.7–13.6), suggesting that apart from pholcodine, other environmental factors can also lead to sensitisation to NMBAs. Pholcodine and quaternary ammonium sIgEs had a high negative predictive value (99.9%) but a very low positive predictive value (<3%) for identifying NMBA-related reactions. Patients exposed to pholcodine 12 months before NMBA exposure have a significantly higher risk of an NMBA-related anaphylaxis. The low positive predictive values of pholcodine and quaternary ammonium sIgEs precludes their use to identify a population with a high risk of NMBA-related anaphylaxis. NCT02250729. [ABSTRACT FROM AUTHOR]

Pholcodine and guaiacol are widely used together in pharmaceutical syrups for cough treatment. On the other hand, the Ultra Performance Liquid Chromatographic technique is characterized by having the power of increasing chromatographic efficiency and decreasing run time compared to the traditional High Performance Liquid Chromatographic one. In this work, this power was exploited for the simultaneous determination of pholcodine, guaiacol along with three guaiacol impurities, namely; guaiacol impurity A, guaiacol impurity B, and guaiacol impurity E. Good separation was achieved by employing Agilent Zorbax C8 column (50 × 2.1 mm) as the stationary phase, and acetonitrile: phosphate buffer pH 3.5 (40: 60, by volume) as a mobile phase. The proposed method was validated as per International Council for Harmonisation guidelines. Linear relationships, at ranges of 50–1000 µg mL−1 for pholcodine and 5–100 µg mL−1 for guaiacol and the three related impurities, were established. Finally, the proposed method was applied for pholcodine and guaiacol determination in Coughpent® syrup and compared favorably to the reported one. [ABSTRACT FROM AUTHOR]

Two recent case–control studies, both published in the British Journal of Anaesthesia , have shown that intake of pholcodine-containing cough medicines during the year preceding general anaesthesia significantly increased the risk of anaphylaxis caused by neuromuscular blocking agents. Both a French multicentre study and a single-centre study from Western Australia offer strong support to the pholcodine hypothesis for IgE-sensitisation to neuromuscular blocking agents. The European Medicines Agency, criticised for not taking preventive action at its first assessment of pholcodine in 2011, finally recommended a stop to sales of all pholcodine-containing medicines throughout the EU on December 1, 2022. Time will tell whether this reduces the incidence of perioperative anaphylaxis in the EU, as in Scandinavia. [ABSTRACT FROM AUTHOR]

Background: The observation that patients presenting for bariatric surgery had a high incidence of neuromuscular blocking agent (NMBA) anaphylaxis prompted this restricted case-control study to test the hypothesis that obesity is a risk factor for NMBA anaphylaxis, independent of differences in pholcodine consumption.Methods: We compared 145 patients diagnosed with intraoperative NMBA anaphylaxis in Western Australia between 2012 and 2020 with 61 patients with cefazolin anaphylaxis with respect to BMI grade, history of pholcodine consumption, sex, age, comorbid disease, and NMBA type and dose. Confounding was assessed by stratification and binomial logistic regression.Results: Obesity (odds ratio [OR]=2.96, χ2=11.7, P=0.001), 'definite' pholcodine consumption (OR=14.0, χ2=2.6, P<0.001), and female sex (OR=2.70, χ2=9.61, P=0.002) were statistically significant risk factors for NMBA anaphylaxis on univariate analysis. The risk of NMBA anaphylaxis increased with BMI grade. Confounding analysis indicated that both obesity and pholcodine consumption remained important risk factors after correction for confounding, but that sex did not. The relative rate of rocuronium anaphylaxis was estimated to be 3.0 times that of vecuronium using controls as an estimate of market share, and the risk of NMBA anaphylaxis in patients presenting for bariatric surgery was 8.8 times the expected rate (74.9 vs 8.5 per 100 000 anaesthetic procedures).Conclusions: Obesity is a risk factor for NMBA anaphylaxis, the risk increasing with BMI grade. Pholcodine consumption is also a risk factor, and this is consistent with the pholcodine hypothesis. Rocuronium use is associated with an increased risk of anaphylaxis compared with vecuronium in this population. [ABSTRACT FROM AUTHOR]

The past two decades have seen the full expansion of all fields of Nanotechnology, Chemometrics, Recycling, and Vibration spectroscopy into most of the research areas. The proposed method involves the harmonization of the previously mentioned fields as a vital tool to fulfill the concepts of sustainability and green analytical chemistry. This may reduce the negative impact of analytical laboratory activities on the surrounding environment and enables the implementation of sustainable development principles to analytical laboratories. This work compares the performance of surface enhanced infrared spectroscopy (SEIRA) with traditional chromatographic techniques for quantification of active pharmaceutical ingredients concerning the twelve principles of green analytical chemistry. The used aluminum TLC slides were recycled to be used as a SEIRA substrate. Citrate capped silver nanoparticles were synthesized via one step chemical reduction method, characterized, and deposited on the surface of the recycled aluminum TLC slides to be used as an active mid-infrared surface for quantification of the active pharmaceutical ingredient's combinations. SEIRA coupled with PLSR chemometric tool was developed, validated and successfully applied to mixtures having diverged concentration ranges (5, 30 and 500 μg ml−1) of Pholcodine, Pseudoephedrine and Paracetamol, respectively. Pholcodine is a synthetic or semi-synthetic opium alkaloid that derived from morphine. Pseudoephedrine is a sympathomimetic agent that is prohibited in sports competitions by the world antidoping agency at certain concentration levels. Paracetamol has analgesic and antipyretic actions. After optimization of the method parameters and number of latent factors, a good linear calibration model of the PLSR strategy was obtained as indicated by the lowest root mean square error of calibration and prediction obtained and the regression coefficients R2 of 0.9912, 0.9888, and 0.9992, respectively. The calibration ranges for the three drugs in their pharmaceutical combinations was 2.5–12.5, 15–75 and 200–600 μg ml−1, respectively. The method showed high resolving power for the three drugs in presence of excipients and good recoveries were obtained in a range of 97–102% with relative standard deviation < 2. The developed lab on a chip SEIRA analyzer in comparison to the traditional chromatographic techniques does not only fulfill the twelve principles of GAC but also it combines the merits of high throughput straightforward fingerprint analyzers, portable to measure samples on its place, cost effective, reduced sample volume and solvent consumption, coupled with intelligent chemometric tools to analyze multiple samples, reduced trials and time to get results. Image 1 • Surface enhanced infrared spectroscopy coupled to chemometric tools for quantification of pharmaceutical combinations. • One step synthesis of citrate capped silver nanoparticles. and its characterization using different techniques • A cost-effective substrate was prepared using the nanoparticles deposited on recycled aluminum TLC plates. • The method has been applied for quantification of pholcodine, pseudoephedrine and paracetamol pharmaceutical combinations. • The opportunities for SEIRA to fulfill the twelve principles of GAC in comparison to traditional techniques were discussed. [ABSTRACT FROM AUTHOR]

Guaiacol (GUA) and pholcodine (PHO) were simultaneously determined in a pharmaceutical syrup using RP-HPLC with UV detection. The separation was performed using X-Bridge C8 column (100 mm × 4.6 mm, 2.5 μm particle size) and a mobile phase of acetonitrile – phosphate buffer (pH 6.8; 50 mM) (25:75, v/v) at a flow rate of 0.55 mL/min. The column temperature was adjusted to 35°C, and the detector was set to measure the absorbance at 238 nm. The ICH guidelines were followed to validate the method. The linearity was studied over 6.0 – 70 μg/mL and 4 – 420 μg/mL ranges for GUA and PHO, respectively. Linear relationships were obtained over the specified concentration ranges with correlation coefficients of 0.9989 for GUA and 0.9999 for PHO. The limits of detection were also determined and found to be 2 μg/mL for GUA and 1.2 μg/mL for PHO. The proposed method was applied for the determination of both drugs in Coughpent syrup; the results comply with the label claim (0.1572g/120mL for PHO and 0.0237g/120mL for GUA). [ABSTRACT FROM AUTHOR]

[Display omitted] • UPLC-MS/MS for determination of pholcodine, pseudoephedrine and paracetamol. • Liquid-liquid extraction allowed effective plasma extraction and purification. • Validated in accordance with FDA guidelines. • The method was applied in in-vivo pharmacokinetic study for drug-drug interaction. • Assessing COVID-19 drugs effect on co-administration of theses antitussive drugs. The symptoms of the viral infection COVID-19, which range from mild to severe, can include fever, coughing, sore throats, malaise, headaches, and a loss of taste or smell. Fever and cough are the most typical symptoms of COVID-19, and in more severe cases, it can make breathing difficult. Hence, in this in-vivo study, we studied the effect of the simultaneous co-administration of COVID-19 treatment drugs (azithromycin, dexamethasone, and hydroxychloroquine) on the pharmacokinetics of the antitussive drugs combination: pholcodine, pseudoephedrine and paracetamol in rats. For the simultaneous determination of pholcodine, pseudoephedrine, and paracetamol in rat plasma, a UPLC-MS/MS technique was developed and approved. a mobile phase made up of 0.15% aqueous formic acid: acetonitrile (20:80, v/v) was used using an Xterra C18 MS column (3.5 m, 4.6 × 50 mm). The detection procedure involved the employment of a multiple reaction monitoring mode utilizing triple-quadrupole tandem mass spectrometer. The concentration range for pholcodine, pseudoephedrine, and paracetamol was linear across 12–1000 ng/ml, 10–550 ng/ml, and 400–30000 ng/ mL, respectively. The results show that the coefficient of variation is satisfactory at quality control samples for all the mentioned drugs, confirming the accuracy and precision of the method. This approach was successfully implemented in a rat drug-drug pharmacokinetic interaction study to determine whether the co-administration of COVID-19 protocol medications would affect the bioavailability of pholcodine, pseudoephedrine and paracetamol. It was found that azithromycin, dexamethasone, and hydroxychloroquine co-administration significantly affect the bioavailability of these drugs, increasing their systemic exposure as a result and this could potentially lead to increasing adverse effects. Therefore, healthcare professionals should consider the potential drug-drug interaction when prescribing these medications to COVID-19 patients. [ABSTRACT FROM AUTHOR]

Guaifenesin and pholcodine are frequently co-formulated in certain dosage forms. A new fast first derivative synchronous spectrofluorometric method has been used for their simultaneous analysis in mixtures. Here, first derivative synchronous spectrofluorometry enabled the successful simultaneous estimation of guaifenesin at 283 nm and pholcodine at 275 nm using a wavelength difference (Δλ) of 40 nm. The method was fully validated following International Council of Harmonization guidelines. For guaifenesin and pholcodine, linearity was determined within the corresponding ranges of 0.05-0.30 and 0.10-6.0 μg/ml. The two drugs were effectively analyzed using the developed approach in their respective formulations, and the results showed good agreement with those attained using reference methods. The method demonstrated excellent sensitivity, with detection limits down to 0.007 and 0.030 μg/ml and quantitation limits of 0.020 and 0.010 μg/ml for guaifenesin and pholcodine, respectively. Therefore, the procedure was successful in determining these drugs simultaneously in vitro in spiked plasma samples and syrup dosage form. The developed methodology also offered an environmentally friendly advantage by utilizing water as the optimal diluting solvent throughout the whole work. Different greenness approaches were investigated to ensure the method's ecofriendly properties., (© 2024 John Wiley & Sons Ltd.)

Résumé L’allergie aux curares est une complication souvent grave survenant en cours d’anesthésie. C’est le plus souvent une réaction immunologique IgE médiée. Tous les curares peuvent induire des réactions anaphylactiques. Le rocuronium et le suxaméthonium induisent plus fréquemment des réactions anaphylactiques que les autres curares. L’allergie aux curares est imprévisible en dehors d’antécédent de réaction grave inexpliquée survenue lors d’anesthésie antérieure. Le plus souvent le patient fera le choc anaphylactique sans avoir reçu un curare au préalable. Ceci suggère une sensibilisation croisée avec d’autres molécules contenant l’épitope des curares l’ion ammonium quaternaire. Différents modes de sensibilisation sont actuellement en cours d’investigation. La pholcodine principe actif de sirops antitussifs pourrait être un mode important de sensibilisation. L’antidote du rocuronium pourrait avoir un effet bénéfique sur les réactions anaphylactiques induites par le rocuronium. Cependant, elle a déjà induit des réactions anaphylactiques. En cas de survenue d’un choc anaphylactique, un bilan de la réaction et la recherche d’allergie croisée sont nécessaires déterminer un curare utilisable pour les anesthésies ultérieures. Anaphylaxis related to neuromuscular blocking agents (NMBA) is a life-threatening complication occurring during anaesthesia. It is an immediate hypersensitivity reaction that is mediated by IgE in more than 60% of cases. Amongst NMBAs, rocuronium and suxamethonium induce anaphylactic reactions more frequently than any other agents. Anaphylaxis related to NMBA is unpredictable other than in patients previously presenting unexplained severe reaction during anaesthesia. The fact that most patients affected have no previous history of NMBA use suggests cross-sensitization with other substances containing the epitope of the quaternary ammonium ion. Different modes of sensitization are currently under investigation. The cough-suppressant pholcodine could constitute an important pathway for sensitization. While the antidote to rocuronium has been reported as exerting beneficial effects on rocuronium-induced anaphylactic reactions, it has nevertheless already induced anaphylactic reactions. When anaphylactic shock occurs, allergy screening is mandatory to investigate cross-sensitization amongst NMBAs and to identify a safe NMBA for subsequent anaesthesia. [ABSTRACT FROM AUTHOR]

Background As a strong inducer of IgE antibodies to substituted ammonium ion epitopes ( QAI), pholcodine ( PHO) is a postulated cause of allergic anaphylaxis to neuromuscular blocking agents ( NMBAs). Three years after withdrawal of PHO in Norway, a significant reduction in IgE sensitization and anaphylaxis reporting was seen. Objective Six-year follow-up study on the effects of PHO withdrawal on IgE sensitization and anaphylaxis reporting. Methods From 650 acute consecutive reports (2005-2013) to the Norwegian Network for Anaphylaxis under Anaesthesia ( NARA), total number of reports on suspected anaphylactic reactions, number of reactions where NMBAs were administered, number of reactions where serum IgE antibodies (≥0.35 kUA/l) to suxamethonium ( SUX) and PHO were present at time of reaction and anaphylaxis severity grades were retrieved. In addition, NMBA sales and prevalence of IgE sensitization to PHO and SUX among 'allergics' were monitored. Results From baseline period P0 ( PHO on the market) through the first (P1) and second (P2), three-year periods after withdrawal, significant falls in total reports ( P < 0.001) and reports with IgE antibodies to PHO ( P = 0.008) and SUX ( P = 0.001) at time of reaction were found. Total NMBA sales in P2 were 83% of P0, and SUX and rocuronium ( ROC) together made up 86% of sales throughout the study. Five NMBA-related anaphylactic deaths occurred during P0 and P1 and, however, none during P2. Prevalence of IgE sensitization to SUX in 'allergics' fell to 0% at 4 and 5 years after withdrawal. Conclusions Six years after PHO withdrawal, the Norwegian population has become significantly less IgE-sensitized and clinically more tolerant to NMBAs. [ABSTRACT FROM AUTHOR]

Pholcodine is an opiate derivative drug which is widely used in pediatric medicine. In this study, a chemiluminescence (CL) method is described that determines pholcodine in human plasma and syrup samples. This method is based on the fact that pholcodine can greatly enhance the weak CL emission of reaction between tris(1,10 phenanthroline)ruthenium(II), Ru(phen)32+, and acidic Ce(IV). The CL mechanism is described in detail using UV-vis light, fluorescence and CL spectra. Effects of chemical variables were investigated and under optimum conditions, CL intensity was proportional to the pholcodine concentration over the range 4.0 × 10−8 to 8.0 × 10−6 mol L−1. The limit of detection (LOD) (S/N = 3) was 2.5 × 10−8 mol L−1. Percent of relative standard deviations (%RSD) for 3.0 × 10−7 and 3.0 × 10−6 mol L−1 of pholcodine was 2.9 and 4.0%, respectively. Effects of common ingredients were investigated and the method was applied successfully to the determination of pholcodine in syrup samples and human plasma. [ABSTRACT FROM AUTHOR]

Quality control of pharmaceuticals requires development of fast, efficient and reliable methods for determination of active compounds as well as known and very often unknown impurities within defined concentration ranges. In this work, a simple and rapid HPLC-UV-DAD method for identification and quantification of pholcodine process related impurities and some degradation products was developed and validated. Pholcodine and its five structural analogues such as morphine, codeine, thebaine, oripavine, and papaverine were separated in less than 10 minutes using reversed phase LiChrospher C-8 column. For optimal chromatographic performance with reproducible retention times, gradient elution with 2% ammonium hydroxide in water and acetonitrile was used. The method was validated by establishing its selectivity, specifity, sensitivity, linearity, intra- and inter-day precision and robustness. All tested parameters confirmed that the method is suitable for determination of pholcodine and its five impurities in pharmaceutical drug samples. The results obtained from real sample analysis give support to the suitability of the proposed method for the purpose of quality control.

A novel approach for the resolution and quantitation of severely overlapped quaternary mixture of carbinoxamine maleate (CAR), pholcodine (PHL), ephedrine hydrochloride (EPH) and sunset yellow (SUN) in syrup was demonstrated utilizing different spectrophotometric assisted multivariate calibration methods. The applied methods have used different processing and pre-processing algorithms. The proposed methods were partial least squares (PLS), concentration residuals augmented classical least squares (CRACLS), and a novel method; continuous wavelet transforms coupled with partial least squares (CWT-PLS). These methods were applied to a training set in the concentration ranges of 40–100 μg/mL, 40–160 μg/mL, 100–500 μg/mL and 8–24 μg/mL for the four components, respectively. The utilized methods have not required any preliminary separation step or chemical pretreatment. The validity of the methods was evaluated by an external validation set. The selectivity of the developed methods was demonstrated by analyzing the drugs in their combined pharmaceutical formulation without any interference from additives. The obtained results were statistically compared with the official and reported methods where no significant difference was observed regarding both accuracy and precision. [ABSTRACT FROM AUTHOR]

Neuromuscular blocking agents ( NMBAs) are the most commonly implicated drugs in IgE-mediated anaphylaxis during anaesthesia that can lead to perioperative morbidity and mortality. The rate of NMBA anaphylaxis shows marked geographical variation in patients who have had no known prior exposure to NMBAs, suggesting that there may be external or environmental factors that contribute to the underlying aetiology and pathophysiology of reactions. Substituted ammonium ions are shared among NMBAs and are therefore thought to be the main allergenic determinant of this class of drugs. Substituted ammonium ions are found in a wide variety of chemical structures, including prescription medications, over-the-counter medications and common household chemicals, such as the quaternary ammonium disinfectants. Epidemiological studies have shown parallels in the consumption of pholcodine, a nonprescription antitussive drug which contains a tertiary ammonium ion, and the incidence of NMBA anaphylaxis. This link has prompted the withdrawal of pholcodine in some countries, with an ensuing fall in the observed rate of NMBA anaphylaxis. While such observations are compelling in their suggestion of a relationship between pholcodine exposure and NMBA hypersensitivity, important questions remain regarding the mechanisms by which pholcodine is able to sensitize against NMBAs and whether there are other, as yet unidentified, agents that can elicit similar hypersensitivity reactions. This review aims to explore the evidence linking pholcodine exposure to NMBA hypersensitivity and discuss the implications for our understanding of the pathophysiology of these reactions. [ABSTRACT FROM AUTHOR]

• Solubility of Pholcodine (PHO , antitussive drug) in Sc-CO 2 was measured for the first time. • Experiments were conducted on temperatures (308–338 K) and pressures (120–270 bar). • Solubility data were correlated by three density-based models. • Self-consistency of experimental data was confirmed. Pholcodine (PHO , Antitussive Drug) solubility in supercritical carbon dioxide (Sc-CO 2) was measured at temperatures of 308, 318, 328, and 338 K and pressures of 120–270 bar. According to the measurements, mole fractions and solubilities of PHO dissolved in Sc-CO 2 ranged in 2.06–5.93 × 10−4 and 0.721–4.212 g/L, respectively. Three types of models were employed for correlating experimental results: 1) three existing empirical and semi-empirical models with three and six parameters, 2) the cubic equation of Peng-Robinson with the conventional temperature-dependent and independent mixing rule; and 3) regular solution with Hansen solubility parameter, Reddy-Madras and Alwi et al. models as solid-liquid equilibrium models. Based on the results, all applied models accurately described PHO solubility in Sc-CO 2 , although Alwi et al. model led to superior results based on AARD (0.29%) and AI C c criterion (-647.697). Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]

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Quality control of pharmaceuticals requires development of fast, efficient and reliable methods for determination of active compounds as well as known and very often unknown impurities within defined concentration ranges. In this work, a simple and rapid HPLC-UV-DAD method for identification and quantification of pholcodine process related impurities and some degradation products was developed and validated. Pholcodine and its five structural analogues such as morphine, codeine, thebaine, oripavine, and papaverine were separated in less than 10 minutes using reversed phase LiChrospher C-8 column. For optimal chromatographic performance with reproducible retention times, gradient elution with 2% ammonium hydroxide in water and acetonitrile was used. The method was validated by establishing its selectivity, specifity, sensitivity, linearity, intra- and inter-day precision and robustness. All tested parameters confirmed that the method is suitable for determination of pholcodine and its five impurities in pharmaceutical drug samples. The results obtained from real sample analysis give support to the suitability of the proposed method for the purpose of quality control. [ABSTRACT FROM AUTHOR]

To cite this article: Johansson SGO, Florvaag E, Öman H, Poulsen LK, Mertes PM, Harper NJN, Garvey LH, Gerth van Wijk R, Metso T, Irgens A, Dybendal T, Halsey J, Seneviratne SL, Guttormsen AB. National pholcodine consumption and prevalence of IgE-sensitization: a multicentre study. Allergy 2010; 65: 498–502. Background: The aim of this study was to test, on a multinational level, the pholcodine (PHO) hypothesis, i.e. that the consumption of PHO-containing cough mixtures could cause higher prevalence of IgE antibodies to PHO, morphine (MOR) and suxamethonium (SUX). As a consequence the risk of anaphylaxis to neuromuscular blocking agents (NMBA) will be increased. Methods: National PHO consumptions were derived from the United Nations International Narcotics Control Board (INCB) database. IgE and IgE antibodies to PHO, MOR, SUX and P-aminophenyl-phosphoryl choline (PAPPC) were measured in sera from atopic individuals, defined by a positive Phadiatop® test (>0.35 kUA/l), collected in nine countries representing high and low PHO-consuming nations. Results: There was a significant positive association between PHO consumption and prevalences of IgE-sensitization to PHO and MOR, but not to SUX and PAPPC, as calculated both by exposure group comparisons and linear regression analysis. The Netherlands and the USA, did not have PHO-containing drugs on the markets, although the former had a considerable PHO consumption. Both countries had high figures of IgE-sensitization. Conclusion: This international prevalence study lends additional support to the PHO hypothesis and, consequently, that continued use of drugs containing this substance should be seriously questioned. The results also indicate that other, yet unknown, substances may lead to IgE-sensitization towards NMBAs. [ABSTRACT FROM AUTHOR]

Copyright of Revue Francaise d'Allergologie is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Neuromuscular blocking agents (NMBAs) can cause anaphylaxis through immunoglobulin E (IgE) antibodies that bind quaternary ammonium ion epitopes. These epitopes are present in numerous common chemicals and drugs, exposure to which, theoretically, could be of importance in the development and maintenance of the IgE sensitization promoting allergic reactions. Pholcodine is one such drug, which in a recent pilot study was shown to induce a remarkable increase in serum IgE levels in two IgE-sensitized individuals. The present study explores the effect of pholcodine exposure on IgE in a population with previously diagnosed IgE-mediated anaphylaxis towards NMBAs. Methods: Seventeen patients were randomized to 1 week’s exposure with cough syrup containing either pholcodine or guaifenesin. The primary variables serum IgE and IgE antibodies towards pholcodine, morphine and suxamethonium were measured before and 4 and 8 weeks after start of exposure. Results: Patients exposed to pholcodine had a sharp rise in levels of IgE antibodies towards pholcodine, morphine and suxamethonium, the median proportional increases 4 weeks after exposure reaching 39.0, 38.6 and 93.0 times that of the base levels respectively. Median proportional increase of IgE was 19.0. No changes were observed in the guaifenesin group. Conclusion: Serum levels of IgE antibodies associated with allergy towards NMBAs increase significantly in sensitized patients after exposure to cough syrup containing pholcodine. Availability of pholcodine should be restricted by medical authorities because of the potential risk of future allergic reactions to muscle relaxants. [ABSTRACT FROM AUTHOR]

The acid–base properties of pholcodine, a cough-depressant agent, and related compounds including metabolites were studied by 1H NMR-pH titrations, and are characterised in terms of macroscopic and microscopic protonation constants. New N-methylated derivatives were also synthesized in order to quantitate site- and nucleus-specific protonation shifts and to unravel microscopic acid–base equilibria. The piperidine nitrogen was found to be 38 and 400 times more basic than its morpholine counterpart in pholcodine and norpholcodine, respectively. The protonation data show that the molecule of pholcodine bears an average of positive charge of 1.07 at physiological pH, preventing it from entering the central nervous system, a plausible reason for its lack of analgesic or addictive properties. The protonation constants of pholcodine and its derivatives are interpreted by comparing with related molecules of pharmaceutical interest. The pH-dependent relative concentrations of the variously protonated forms of pholcodine and morphine are depicted in distribution diagrams. [ABSTRACT FROM AUTHOR]

Background: A previous study showed a relation between pholcodine (PHO) consumption, prevalence of IgE-sensitization to PHO, morphine (MOR) and suxamethonium (SUX) and anaphylaxis to neuromuscular blocking agents (NMBA). The purpose of this pilot study was to explore the effect on IgE production, in IgE-sensitized and nonsensitized individuals, of exposure to cough syrup and environmental chemicals containing PHO, MOR and SUX related allergenic structures. Methods: Serum concentrations of IgE and IgE antibodies to PHO, MOR and SUX allergens measured by ImmunoCAPTM (Pharmacia Diagnostics, Uppsala, Sweden) were followed after intake of cough syrup, or exposure to confectionary and other household chemicals containing various amounts of substances cross-reacting with PHO, MOR and SUX. Results: Cough syrup containing PHO gave, in sensitized individuals, within 1–2 weeks, an increase of IgE of 60–105 times and of IgE antibodies to PHO, MOR and SUX in the order of 30–80 times. The tested confectionary did not have any similar stimulating effect but seemed to counteract the expected decrease of IgE. No effect was seen in nonsensitized individuals. The PHO stimulated IgE showed a nonspecific binding to ImmunoCAP with common allergens and glycine background ImmunoCAP that was up to 10-fold higher than that of monomeric myeloma-IgE at twice the concentration. Conclusions: It seems as cough syrups containing PHO have a most remarkable IgE boostering effect in persons IgE-sensitized to PHO, MOR and SUX related allergens. Household chemicals containing such allergenic epitopes seem capable of some, minor, stimulation. [ABSTRACT FROM AUTHOR]