Harmonization of strategies for the validation of quantitative analytical procedures: a SFSTP proposal part IV. Examples of application

The free cortisol calculated: correlation with the free cortisol concentrations measured with liquid chromatography-tandem mass spectrometry after equilibrium dialysis and establishment of reference intervals

BACKGROUND

Changes in cortisol binding globulin (CBG) impact the total serum cortisol concentration and affect the accurate assessment of adrenal function. Free biologically cortisol can be calculated using different equations or directly measured after complicated procedures.

METHODS

The free cortisol index (FCI) obtained using the Bonte formula as well as the free cortisol concentration calculated (Coolens equation) were first estimated for 45 healthy workers. The CBG level was determined by a competitive radioimmunoassay and the total cortisol concentration, was measured with an electrochemiluminescent assay. The correlations between FCI, the free cortisol concentrations calculated and the free cortisol levels measured with liquid chromatography-tandem mass spectrometry after equilibrium dialysis were studied for those 45 samples. Reference limits were established on 158 healthy hospital workers and patients with serum samples collected between 7:30 am and 10 am.

RESULTS

The FCI as well as the free cortisol concentrations calculated obtained for the 45 samples correlated significantly with the free cortisol levels measured. Although the cortisol and CBG levels were statistically higher in women using contraceptives compared with women not taking them as well as men, the calculated FCI and free cortisol concentrations did not differ between these groups. The medians (P2.5-P97.5) obtained for the 158 healthy workers were respectively 26.4% (12.3-51.6%) and 10.6 nmol/L (4.3-26.7 nmol/L).

CONCLUSIONS

This study highlighted a significant correlation between the FCI, the free cortisol concentrations calculated and the free cortisol levels measured with LC-MS/MS, it has also allowed the establishment of reference intervals for calculated FCI and free cortisol.

Cistracurium Besylate 10 mg/mL Solution Compounded in a Hospital Pharmacy to Prevent Drug Shortages: A Stability Study Involving Four Degradation Products

BACKGROUND

Stability study of a 10 mg/mL injectable cisatracurium solution stored refrigerated in amber glass ampoules for 18 months (M18).

METHODS

4000 ampoules were aseptically compounded using European Pharmacopoeia (EP)-grade cisatracurium besylate, sterile water for injection, and benzenesulfonic acid. We developed and validated a stability-indicating HPLC-UV method for cisatracurium and laudanosine. At each stability study time point, we recorded the visual aspect, cisatracurium and laudanosine levels, pH, and osmolality. Sterility, bacterial endotoxin content, and non-visible particles in solution were checked after compounding (T0) and after M12 and M18 of storage. We used HPLC-MS/MS to identify the degradation products (DPs).

RESULTS

During the study, osmolality remained stable, pH decreased slightly, and the organoleptic properties did not change. The number of non-visible particles remained below the EP's threshold. Sterility was preserved, and bacterial endotoxin level remained below the calculated threshold. Cisatracurium concentration remained within the ±10% acceptance interval for 15 months and then decreased to 88.7% of C0 after M18. The laudanosine generated accounted for less than a fifth of the cisatracurium degradation, and three DPs were generated-identified as EP impurity A, impurities E/F, and impurities N/O.

CONCLUSION

Compounded 10 mg/mL cisatracurium injectable solution is stable for at least 15 months.

Emerging analytical techniques for pharmaceutical quality control: Where are we in 2022?

Quality control is a fundamental and critical activity in the pharmaceutical industry that guarantees the quality of medicines. QC analyses are currently performed using several well-known techniques, mainly liquid and gas chromatography. However, current trends are focused on the development of new techniques to reduce analysis time and cost, to improve the performances and decrease ecological footprint. In this context, analytical scientists developed and studied emerging technologies based on spectroscopy and chromatography. The present review aims to give an overview of the recent development of vibrational spectroscopy, supercritical fluid chromatography and multi-dimensional chromatography. Selected emerging techniques are discussed using SWOT analysis and published pharmaceutical QC applications are discussed.

Salt-Induced Homogeneous Liquid–Liquid Microextraction of Piroxicam and Meloxicam from Human Urine Prior to Their Determination by HPLC-DAD

A salt-induced homogeneous liquid–liquid microextraction (SI-HLLME) protocol combined with high-performance liquid chromatography–diode array detection is presented for the first time for the determination of piroxicam and meloxicam in human urine. The main parameters affecting the performance of the sample preparation protocol were optimized by means of a two-step experimental design (i.e., 2-level fractional factorial design and Box–Behnken design). Following its optimization, the proposed method was thoroughly validated in terms of the total error concept in order to take into consideration the random and systematic errors. For the target analytes, accuracy profiles were constructed, and they were used as graphical decision-making tools. In all cases, the β-expectation tolerance intervals complied with the acceptance criteria of ±15%, proving that 95% of future results will fall within the defined bias limits. The limits of detection were 0.02 μg mL−1 and 0.03 μg mL−1 for piroxicam and meloxicam, respectively. The relative standard deviations were lower than 4.4% in all cases, and the mean relative biases ranged between −5.7 and 3.4% for both drugs. The proposed scheme is simple and rapid, while it is characterized by high sample throughput. Moreover, SI-HLLME requires reduced sample and reagent consumption, according to the requirements of Green Analytical Chemistry.

Development and Validation of an HPLC-UV Method for the Dissolution Studies of 3D-Printed Paracetamol Formulations in Milk-Containing Simulated Gastrointestinal Media

Herein, a simple and rapid HPLC method for the determination of paracetamol milk-containing biorelevant media is proposed. The separation of the analyte from the milk-containing biorelevant media was accomplished isocratically using a mobile phase containing 25 mM phosphate buffer (pH = 3.0) and methanol, 80:20, v/v at a flow rate of 1 mL min⁻¹. Following a protein precipitation-based sample clean-up, a thorough investigation of the effect of the precipitation reagent (methanol, acetonitrile, 10% v/v trifluoroacetic acid solution) on the analyte recovery was performed. The matrix effect was assessed in each biorelevant medium by comparing the slopes of the calibration curves of aqueous and matrix-matched calibration curves. The method was comprehensively validated using the accuracy profiles. The β-expectation tolerance intervals did not exceed the acceptance criteria of ±15%, meaning that 95% of future results will be included in the defined bias limits. The relative bias ranged between −4.5 and +3.9% for all analytes, while the RSD values for repeatability and intermediate precision were less than 2.7% and 3.0%, respectively. The achieved limit of detection (LOD) was 0.02 μg mL⁻¹ and the lower limits of quantitation (LLOQ) were established as 10 μg mL⁻¹, which corresponded to 2% of the highest expected concentration of paracetamol. The proposed scheme was utilized for the determination of paracetamol in dissolution studies of its 3D-printed formulation in milk-containing biorelevant media.

HPLC Determination of Colistin in Human Urine Using Alkaline Mobile Phase Combined with Post-Column Derivatization: Validation Using Accuracy Profiles

In this study, the development, validation, and application of a new liquid chromatography post-column derivatization method for the determination of Colistin in human urine samples is demonstrated. Separation of Colistin was performed using a core–shell C₁₈ analytical column in an alkaline medium in order (i) to be compatible with the o-phthalaldehyde-based post-column derivatization reaction and (ii) to obtain better retention of the analyte. The Colistin derivative was detected spectrofluorometrically (λ_ext/λ_em = 340/460 nm) after post-column derivatization with o-phthalaldehyde and N-acetyl cysteine. The post-column derivatization parameters were optimized using the Box–Behnken experimental design, and the method was validated using the total error concept. The β-expectation tolerance intervals did not exceed the acceptance criteria of ±15%, meaning that 95% of future results would be included in the defined bias limits. The limit of detection of the method was adequate corresponding to 100 nmol·L⁻¹. The mean analytical bias (expressed as relative error) in the spiking levels was suitable, being in the range of −2.8 to +2.5% for both compounds with the percentage relative standard deviation lower than 3.4% in all cases. The proposed analytical method was satisfactorily applied to the analysis of the drug in human urine samples.

Physicochemical Stability of a Novel Tacrolimus Ophthalmic Formulation for the Treatment of Ophthalmic Inflammatory Diseases

Tacrolimus is an immunosuppressant used to treat a large variety of inflammatory or immunity-mediated ophthalmic diseases. However, there are currently no commercial industrial forms available that can provide relief to patients. Various ophthalmic formulations have been reported in the literature, but their stability has only been tested over short periods. The objective of this study was to evaluate the physicochemical stability of a preservative-free tacrolimus formulation (0.2 and 1 mg/mL) at three storage temperatures (5 °C, 25 °C and 35 °C) for up to nine months in a multidose eyedropper. Analyses performed were the following: visual inspection and chromaticity, turbidity, viscosity, size of micelles, osmolality and pH measurements, tacrolimus quantification by a stability-indicating liquid chromatography method, breakdown product research, and sterility assay. In an in-use study, tacrolimus quantification was also performed on the drops emitted from the eyedroppers. All tested parameters remained stable during the nine month period when the eyedrops were stored at 5 °C. However, during storage at 25 °C and 35 °C, several signs of chemical instability were detected. Furthermore, a leachable compound originating from a silicone part of the eyedropper was detected during the in-use assay. Overall, the 0.2 mg/mL and 1 mg/mL tacrolimus ophthalmic solutions were physicochemically stable for up to nine months when stored at 5 °C.

A Validated HPLC-PDA-HRMS Method to Investigate the Biological Stability and Metabolism of Antiparasitic Triterpenic Esters

Pentacyclic triterpenes (PTs) are commonly found in medicinal plants with well-known antiparasitic effects. Previous research on C-3 and C-27 triterpenic esters showed effective and selective in vitro antiparasitic activities and in vivo effectiveness by parenteral routes. The aim of this study was to determine triterpenic esters' stability in different biological-like media and the main microsomal degradation products. An HPLC-PDA method was developed and validated to simultaneously analyze and quantify bioactive triterpenic esters in methanol (LOQ: 2.5 and 1.25-100 µg/mL) and plasma (LOQ: 5-125 µg/mL). Overall, both triterpenic esters showed a stable profile in aqueous and buffered solutions as well as in entire plasma, suggesting gaining access to the ester function is difficult for plasma enzymes. Conversely, after 1 h, 30% esters degradation in acidic media was observed with potential different hydrolysis mechanisms. C-3 (15 and 150 µM) and C-27 esters (150 µM) showed a relatively low hepatic microsomal metabolism (<23%) after 1 h, which was significantly higher in the lowest concentration of C-27 esters (15 µM) (>40% degradation). Metabolic HPLC-PDA-HRMS studies suggested hydrolysis, hydroxylation, dehydration, O-methylation, hydroxylation and/or the reduction of hydrolyzed derivatives, depending on the concentration and the position of the ester link. Further permeability and absorption studies are required to better define triterpenic esters pharmacokinetic and specific formulations designed to increase their oral bioavailability.

Machine Learning for Process Monitoring and Control of Hot-Melt Extrusion: Current State of the Art and Future Directions

In the last few decades, hot-melt extrusion (HME) has emerged as a rapidly growing technology in the pharmaceutical industry, due to its various advantages over other fabrication routes for drug delivery systems. After the introduction of the ‘quality by design’ (QbD) approach by the Food and Drug Administration (FDA), many research studies have focused on implementing process analytical technology (PAT), including near-infrared (NIR), Raman, and UV–Vis, coupled with various machine learning algorithms, to monitor and control the HME process in real time. This review gives a comprehensive overview of the application of machine learning algorithms for HME processes, with a focus on pharmaceutical HME applications. The main current challenges in the application of machine learning algorithms for pharmaceutical processes are discussed, with potential future directions for the industry.

Multi-class analysis of 30 antimicrobial residues in poultry feathers by liquid chromatography tandem mass spectrometry

Poultry feathers are nowadays partially re-introduced into the animal food chain and the environment. They are valorised by their transformation into feather meal in order to be used as fertilisers in agriculture but also in animal feed (in particular, pet food and fish feed). However, unlike food producing animals for humans, feathers from poultry animals are not subject to a ban or regulatory limits on the presence of antibiotic residue after veterinary treatment. Feathers could therefore be a potential reservoir of antibiotic residues, unintentionally exposing the environment and animals through food, which might contribute to the emergence of antibiotic resistance. To this end, a multi-class liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) was developed for the detection and determination of residues of 30 antibiotics from eight groups of antibacterial (quinolones, lincosamides, macrolides, penicillins, phenicols, tetracyclines, sulphonamides and diaminopyrimidines) in feathers. The extraction of the analytes from the feathers was carried out by the salting out technique. The separation of the analytes employed a Kinetex C18 column. Quantification was made using internal standards. All analytes have been validated according to the performance criteria of Decision 2002/657/EC. Trueness of the method ranged from to 93% to 111% for all analytes and intermediate precision were to 1.2-18.8%. The limits of quantification (LOQ) were from 13 to 150 µg kg^-1 depending on the analytes. The method is suitable for the monitoring and quantification of antibiotic residues in feathers over the range 13-600 µg kg^-1 depending on the compound.

Stability study of a compounded oral solution of nicardipine for the treatment of hypertension in children

Nicardipine is an antihypertensive drug that may be used off-label by oral route to treat hypertension in children. Currently commercially available tablets are inappropriate for oral use in children and manufactured hard capsules are not suitable for easy dose individualization to achieve target blood pressure. We aimed to fulfill this lack of appropriate dose forms by developing an oral liquid formulation of nicardipine. We compounded an extemporaneous 2 mg/mL nicardipine solution in InOrpha® vehicle for oral use with 1% polysorbate 80. A HPLC-MS/MS stability-indicating method was developed and validated. The stability was assessed under room temperature and refrigerated storage conditions. Nicardipine concentration remained above 95% of the initial concentration for 90 days in both storage conditions, without apparition of degradation products. Organoleptic parameters, pH, osmolality, viscosity and density were assessed and remained stable throughout storage. A uniformity of content was maintained before and after agitation of the packaging bottles. Mass uniformity of delivered doses was also ensured. Finally, the formulation met the Pharmacopoeia specifications for microbiological contaminations. In this study we report a compounded formulation of nicardipine for oral use in pediatrics. This solution, which could be easily manufactured, is being used in our hospital. Pharmacological and clinical parameters including bioavailability, pharmacokinetics, efficacy and tolerance remain to be assessed.

Development and Validation of an Automated Zone Fluidics-Based Sensor for In Vitro Dissolution Studies of Captopril Using Total Error Concept

In the present research, a zone fluidics-based automated sensor for the analysis of captopril in in vitro dissolution samples is reported. Captopril is reacted under flow conditions with Ni(II) (10 mmol L^-1) in alkaline medium (0.15% v/v NH₃) to form a stable derivate, which is monitored spectrophotometrically at 340 nm. The chemical and instrumental parameters were carefully investigated and optimized. The validation of the developed method was performed in the range of 5 to 120% of the expected maximum concentration using the accuracy profiles as a graphical decision-making tool. The β-expectation tolerance intervals did not exceed the acceptance criteria of ±10%, which means that 95% of future results will be encompassed in the defined bias limits. The variation of the relative bias ranged between -2.3% and 3.5% and the RSD values for repeatability and intermediate precision were lower than 2.3% in all cases. The limit of detection (LOD), and the lower and the upper limit of quantification (LLOQ, ULOQ) were satisfactory and found to be 1%, 5% and 120% (corresponding to 0.6, 2.78 and 66.67 μg mL^-1 in dissolution medium). The developed method was successfully applied for the analysis of captopril in dissolution tests of two commercially available batches.

Multi-element Quantification in Parenteral Nutrition Mixture by MP-AES and Comparison with ICP-AES

Background:

Individualized parenteral nutrition requires tailor-made preparation in hospital pharmacy followed by suitable quality control, including electrolytic content determination within complex and variable admixtures, containing up to 50 ingredients.

Materials and Methods:

An analytical tool has been developed to simultaneously quantify four major electrolytes in parenteral in parenteral nutrition mixtures (i.e., sodium, potassium, magnesium and calcium) using microwave plasma atomic emission spectroscopy (MP-AES). A comparison with reference inducted coupled plasma atomic emission spectroscopy (ICP-AES) was conducted. Calibration standard solutions ranged between 0.2 to 5.0 mg.L-1 for sodium, potassium and calcium and 0.1 to 2.5 mg.L-1 for magnesium. Wavelengths used were respectively 422.6 nm, 517.2 nm, 766.4 nm and 589.5 nm for calcium, magnesium, potassium and sodium, respectively. Accuracy profiles were used for the validation protocol.

Results and Conclusion:

The analytical protocol using MP-AES demonstrated high throughput and good sensitivity, thus enabling efficient quality control of manufactured individualized parenteral nutrition mixtures.

Detection of norovirus, hepatitis A and hepatitis E viruses in multicomponent foodstuffs

Among the enteric viruses implicated in foodborne outbreaks, the human norovirus and hepatitis viruses A and E (HAV and HEV) represent a serious public health concern. International standard ISO 15216 proposes methods for detecting HAV and norovirus (genogroups I and II) RNA from soft fruit, leaf, stem and bulb vegetables, bottled water or food surfaces. These methods had not previously been validated for detecting the targeted viruses in other foodstuffs such as multicomponent foods, nor for detecting other viruses in foodstuffs. The aim of this study was to characterise a method derived from the vegetable method described in ISO 15216 to detect HAV, HEV and norovirus in artificially-contaminated multicomponent foodstuffs according to the recent international standard ISO 16140-4. Results showed that the mean recovery rates for all settings did not differ according to the operator. The mean extraction yields ranged from 0.35% to 40.44% for HAV, 5.19% to 100% for HEV, 0.10% to 40.61% for norovirus GI and 0.88% to 69.16% for norovirus GII. The LOD₉₅ was 10² genome copies/g for HAV, HEV and norovirus GII and 10³ genome copies/g for norovirus GI. The LOQ was 2.90 × 10⁴, 1.40 × 10³, 1.60 × 10⁴ and 1.30 × 10⁴ genome copies/g for HAV, HEV, norovirus GI and norovirus GII respectively. The MNV-1 process control was detected in 120 out of 128 RNA extracts analysed and was recovered with an efficiency of between 3.83% and 50.22%. The mean inhibition rates of quantitative real-time RT-PCR reaction ranged from 3.25% to 28.70% and varied significantly with the type of food matrix. The described method could be used to detect viruses in composite food products for routine diagnosis needs.

Simultaneous determination of 8 beta-lactams and linezolid by an ultra-performance liquid chromatography method with UV detection and cross-validation with a commercial immunoassay for the quantification of linezolid

Linezolid and beta-lactams are anti-infective drugs frequently used in intensive care unit patients. Critical illness could induce alterations of pharmacokinetic parameters due to changes in the distribution, the metabolism and the elimination process. Therapeutic drug monitoring (TDM) is therefore recommended to prevent mainly under-dosing of beta-lactams or hematological and neurological toxicities of linezolid. In Multi-or Extensively-Drugs Resistant-Tuberculosis Bacteria, the regimen could include linezolid with meropenem and amoxicillin/clavulanate justifying the development of a method allowing their simultaneous quantification. The aim of this work was to develop an in-house ultra-performance liquid chromatography method with UV detection (UHPLC-PDA) allowing the simultaneous determination of 8 beta-lactams (amoxicillin, aztreonam, cefepime, ceftazidime, ceftriaxone, cefuroxime, meropenem and piperacillin) and linezolid and to cross-validate the linezolid quantification with a new commercial immunoassay (ARK kit) tested on a Cobas analyzer. The main advantages of the immunoassay are a 24/24 h random access assay which is fully automated and results provided within 2 h. The interference due to potential co-administrated drugs was evaluated on both methods. The preanalytical factors (type of matrix, stability) for linezolid were also investigated. The influence of hemolysis, icteria or lipemia on the spectroscopic detection of the immunoassay was assessed. The analytical performances were evaluated using the accuracy profiles approach with acceptance limits fixed at ±30%. Seventy patient samples were measured using both methods. No cross-reaction with the tested anti-infective drugs as well as no influence of hemolysis, lipemia, icteria were observed. The linezolid concentration could be measured on heparinized plasma or serum without a significant difference and remained stable for at least 72h at 4°C.The UHPLC-PDA method performed well in the analytical range investigated (0.25-50 mg/L for meropenem, 0.75-50 mg/L for linezolid and 1-200 mg/L for other beta-lactams) with an intermediate precision and a relative bias below 7.6 and 7.7%, respectively. The analytical range of the immunoassay was narrower, from 0.85 to 18.5 mg/L. The precision and relative bias were lower than 8.1% and 4.2%, respectively. Results obtained on clinical samples showed an acceptable difference between methods with a mean bias of -1.8% [95% confidence interval: -5.2% - 1.6%]. To conclude, both methods showed acceptable performance to perform TDM of linezolid considering the therapeutic through target of 2-8 mg/L. The choice of the method should be made according to the degree of emergency of the response required and the field of application justifying or not the simultaneous quantification of beta-lactams and linezolid.

Do Ophthalmic Solutions of Amphotericin B Solubilised in 2-Hydroxypropyl-γ-Cyclodextrins Possess an Extended Physicochemical Stability?

Fungal keratitis is a sight-threatening disease for which amphotericin B eye drops is one of the front-line treatments. Unfortunately, there are currently no commercial forms available, and there is little data concerning the long-term stability of compounded formulations based on intravenous dosages forms. New formulations of amphotericin B ophthalmic solutions solubilised with γ-cyclodextrins have shown promising in-vitro results, but stability data is also lacking. The objective of this study was therefore to investigate the stability of a formulation of ready-to-use amphotericin B solubilised in 2-hydroxypropyl-γ-cyclodextrins (AB-HP-γ-CD), for 350 days. An amphotericin B deoxycholate (ABDC) formulation was used as a comparator. Analyses used were the following: visual inspection, turbidity, osmolality and pH measurements, amphotericin B quantification by a stability-indicating liquid chromatography method, breakdown product research, and sterility assay. AB-HP-γ-CD formulation showed signs of chemical instability (loss of amphotericin B) after 28 and 56 days at 25 °C and 5 °C. Adding an antioxidant (ascorbic acid) to the formulation did not improve stability. ABDC formulation showed signs of physical instability (increased turbidy and amphotericin B precipitation) after 28 days and 168 days at 25 °C and 5 °C. As such, AB-HP-γ-CD formulation does not provide long-term stability for ophthalmic amphotericin B solutions.

Stability of Ophthalmic Atropine Solutions for Child Myopia Control

Myopia is an ophthalmic condition affecting more than 1/5th of the world population, especially children. Low-dose atropine eyedrops have been shown to limit myopia evolution during treatment. However, there are currently no commercial industrial forms available and there is little data published concerning the stability of medications prepared by compounding pharmacies. The objective of this study was to evaluate the stability of two 0.1 mg/mL atropine formulations (with and without antimicrobiobial preservatives) for 6 months in two different low-density polyethylene (LDPE) multidose eyedroppers. Analyses used were the following: visual inspection, turbidity, chromaticity measurements, osmolality and pH measurements, atropine quantification by a stability-indicating liquid chromatography method, breakdown product research, and sterility assay. In an in-use study, atropine quantification was also performed on the drops emitted from the multidose eyedroppers. All tested parameters remained stable during the 6 months period, with atropine concentrations above 94.7% of initial concentration. A breakdown product (tropic acid) did increase slowly over time but remained well below usually admitted concentrations. Atropine concentrations remained stable during the in-use study. Both formulations of 0.1 mg/mL of atropine (with and without antimicrobial preservative) were proved to be physicochemically stable for 6 months at 25 °C when stored in LDPE bottles, with an identical microbial shelf-life.

Quantitation of active pharmaceutical ingredient through the packaging using Raman handheld spectrophotometers: A comparison study

Handheld Raman spectroscopy is actually booming. Recent devices improvements aim at addressing the usual Raman spectroscopy issues: fluorescence with shifted-excitation Raman difference spectroscopy (SERDS), poor sensitivity with surface enhanced Raman scattering (SERS) and information only about the sample surface with spatially offset Raman spectroscopy (SORS). While qualitative performances of handheld devices are generally well established, the quantitative analysis of pharmaceutical samples remains challenging. The aim of this study was to compare the quantitative performances of three commercially available handheld Raman spectroscopy devices. Two of them (TruScan and IDRaman mini) are equipped with a 785 nm laser wavelength and operate in a conventional backscattering mode. The IDRaman has the Orbital Raster Scanning (ORS) option to increase the analyzed surface. The third device (Resolve) operates with an 830 nm laser wavelength both in backscattering and in SORS modes. The comparative study was carried out on ibuprofen-mannitol-microcrystalline cellulose ternary mixtures. The concentration of ibuprofen ranged from 24 to 52% (w/w) while the proportions of the two excipients were varied to avoid cross-correlation as much as possible. Analyses were performed either directly through a glass vial or with the glass vial in an opaque polypropylene flask, using a validated FT-NIR spectroscopy method as a reference method. Chemometric analyses were carried out with the Partial Least Squares Regression (PLS-R) algorithm. The quantitative models were validated using the total error approach and the ICH Q2 (R1) guidelines with ± 15% as acceptance limits.

Development and validation of a multiplex UHPLC-MS/MS method for the determination of the investigational antibiotic against multi-resistant tuberculosis macozinone (PBTZ169) and five active metabolites in human plasma

The emergence of Mycobacterium tuberculosis strains resistant to current first-line antibiotic regimens constitutes a major global health threat. New treatments against multidrug-resistant tuberculosis (MDR-TB) are thus eagerly needed in particular in countries with a high MDR-TB prevalence. In this context, macozinone (PBTZ169), a promising drug candidate with an unique mode of action and highly potent in vitro tuberculocidal properties against MDR Mycobacterium strains, has now reached the clinical phase and has been notably tested in healthy male volunteers in Switzerland. To that endeavor, a multiplex UHPLC-MS/MS method has been developed for the sensitive and accurate human plasma levels determination of PBTZ169 along with five metabolites retaining in vitro anti-TB activity. Plasma protein precipitation with methanol was carried out as a simplified sample clean-up procedure followed by direct injection of the undiluted supernatant for the bioanalysis of the six analytes within 5 min, using 1.8 μm reversed-phase chromatography coupled to triple quadrupole mass spectrometry employing electrospray ionization in the positive mode. Stable isotopically-labelled PBTZ169 was used as internal standard (ISTD), while metabolites could be reliably quantified using two unlabeled chemical analogues selected as ISTD from a large in-house analogous compounds library. The overall methodology was fully validated according to current recommendations (FDA, EMEA) for bioanalytical methods, which include selectivity, carryover, qualitative and quantitative matrix effect, extraction recovery, process efficiency, trueness, precision, accuracy profiles, method and instrument detection limits, integrity to dilution, anticoagulant comparison and short- and long-term stabilities. Stability studies on the reduced metabolite H₂-PBTZ169 have shown no significant impact on the actual PBTZ169 concentrations determined with the proposed assay. This simplified, rapid, sensitive and robust methodology has been applied to the bioanalysis of human plasma samples collected within the frame of a phase I clinical study in healthy volunteers receiving PBTZ169.

Validation and uncertainty estimation for trace amounts determination of 25 drugs used in hospital chemotherapy compounding units

The validation and uncertainty assessment of the analytical method developed for the simultaneous determination of 25 anticancer drugs commonly handled in hospital pharmacy was reported. Selected compounds were 5-fluorouracil, cytarabine, fludarabine phosphate, ganciclovir, gemcitabine, dacarbazine, methotrexate, pemetrexed, busulfan, raltitrexed, etoposide phosphate, topotecan, ifosfamide, cyclophosphamide, irinotecan, doxorubicin, epirubicin, daunorubicin, idarubicin, vincristine, vinblastine, vinorelbine, docetaxel and paclitaxel. Accuracy and uncertainty profiles were obtained for all compounds. Quantitative performances were satisfactory in term of specificity, sensitivity, precision and accuracy. Repeatability (1.9-25.4%) and intermediate precision (2.7-29%) were determined for all target compounds. Lower limits of quantification between 1 and 25 ng/mL were obtained. Uncertainty associated to measurement of routine samples was evaluated. The multi-targeted method was specific and reliable and was successfully applied to wipe samples from hospital pharmacy chemotherapy compounding unit and to the determination of outside contamination of vials from pharmaceutical manufacturers.

Optimization and validation of extraction and quantification methods of antimalarial triterpenic esters in Keetia leucantha plant and plasma

The aim of this study is to develop validated methods for the extraction and quantification of antimalarial triterpene esters from Keetia leucantha and from plasma samples. These compounds, showing in vitro and in vivo antiplasmodial activities, were optimally extracted from Keetia leucantha twigs using ultrasounds with dichloromethane and from plasma using protein precipitation with acetonitrile. We then developed and validated HPLC-UV quantification methods, which proved to be selective, accurate, linear, true and precise, both in plant and plasma samples for the eight triterpenic esters in mixture. Based on the total error concept as decision criteria, the validated dosage ranges of the triterpene esters mixture were set between 14.68 and 73.37 μg/mL in plants and 15.90 and 106.01 μg/mL in plasma injected solutions, corresponding to 7.95 and 53.01 μg/mL in plasma. These reliable methods were used to determine effectively triterpene esters content in collected samples, that seems highly variable in plant extracts, and will be helpful to further investigate pharmacokinetics parameters of these interesting bioactive compounds.

Physicochemical and Microbiological Stability of a New Oral Clonidine Solution for Paediatric Use

Background

As many drugs are unavailable for paediatric use, hospital pharmacies are often required to develop suitable formulations themselves. Clonidine is commonly used in paediatrics (in severe hypertension, in opiate withdrawal syndrome, in tics and Gilles de la Tourette syndrome or in anaesthetic premedication) but no appropriate formulation has been drawn up. The aims of this work were to develop an oral solution of clonidine dedicated to children and to assess its physicochemical and microbiological stability.

Methods

Formulation of an oral solution of clonidine hydrochloride suitable for neonates and paediatrics was developed using the active pharmaceutical ingredient (API), with as few excipients as possible and without any complex excipient vehicle. A stability study was made according to GERPAC-SFPC guidelines. At each point in time (D0, D1, D7, D15, D29, D60 and D90), visual aspect (limpidity), pH and osmolality were established. Clonidine concentration was quantified using a stability-indicating HPLC-UV-DAD method previously developed from a forced degradation study and validated according to SFSTP Pharma. Microbiological stability was also tested according to the European Pharmacopeia monograph with the best adapted method (by comparing membrane filtration and inclusion). Solutions were stored in amber glass bottles with an oral adapter for up to 3 months in two different conditions: 5 °C +/– 3 °C and at 25 °C +/– 2 °C with 60 % residual humidity (climatic chamber).

Results

The formulated oral solution is composed of API at a concentration of 10 µg/mL and of potassium sorbate (0.3 %), citric acid, potassium citrate (pH 5 buffer) and sodium saccharine (0.025 %). Forced degradation highlighted six degradation products and the method was validated in the acceptance limits of ± 5 %. On D29, the mean percentages of the initial clonidine concentrations (+/–standard deviation) were 92.95+/–1.28 % in the solution stored at 25 °C +/– 2 °C and 97.44+/–1.21 % when stored at 5 °C +/– 3 °C. On D90, means were respectively 81.82+/–0.41 % and 93.66+/–0.71 %. The visual aspect did not change. Physical parameters remained stable during the study: pH varied from 4.94 to 5.09 and osmolality from 82 to 92 mOsm/kg in the two conditions tested here. Membrane filtration appeared to be the more sensitive method. Whatever the storage conditions,<1 micro-organism/mL was identified (only environmental) with no detected E.coli.

Conclusions

This formulation is stable for at least 3 months at 5 °C +/– 3 °C in amber glass bottles and for one month when stored at room temperature. Microbiological stability was proven in accordance with the European Pharmacopeia.

State of the art in the validation of screening methods for the control of antibiotic residues: is there a need for further development?

Screening methods are used as a first-line approach to detect the presence of antibiotic residues in food of animal origin. The validation process guarantees that the method is fit-for-purpose, suited to regulatory requirements, and provides evidence of its performance. This article is focused on intra-laboratory validation. The first step in validation is characterisation of performance, and the second step is the validation itself with regard to pre-established criteria. The validation approaches can be absolute (a single method) or relative (comparison of methods), overall (combination of several characteristics in one) or criterion-by-criterion. Various approaches to validation, in the form of regulations, guidelines or standards, are presented and discussed to draw conclusions on their potential application for different residue screening methods, and to determine whether or not they reach the same conclusions. The approach by comparison of methods is not suitable for screening methods for antibiotic residues. The overall approaches, such as probability of detection (POD) and accuracy profile, are increasingly used in other fields of application. They may be of interest for screening methods for antibiotic residues. Finally, the criterion-by-criterion approach (Decision 2002/657/EC and of European guideline for the validation of screening methods), usually applied to the screening methods for antibiotic residues, introduced a major characteristic and an improvement in the validation, i.e. the detection capability (CCβ). In conclusion, screening methods are constantly evolving, thanks to the development of new biosensors or liquid chromatography coupled to tandem-mass spectrometry (LC-MS/MS) methods. There have been clear changes in validation approaches these last 20 years. Continued progress is required and perspectives for future development of guidelines, regulations and standards for validation are presented here.

Global approach for the validation of an in-line Raman spectroscopic method to determine the API content in real-time during a hot-melt extrusion process

Since the Food and Drug Administration (FDA) published a guidance based on the Process Analytical Technology (PAT) approach, real-time analyses during manufacturing processes are in real expansion. In this study, in-line Raman spectroscopic analyses were performed during a Hot-Melt Extrusion (HME) process to determine the Active Pharmaceutical Ingredient (API) content in real-time. The method was validated based on a univariate and a multivariate approach and the analytical performances of the obtained models were compared. Moreover, on one hand, in-line data were correlated with the real API concentration present in the sample quantified by a previously validated off-line confocal Raman microspectroscopic method. On the other hand, in-line data were also treated in function of the concentration based on the weighing of the components in the prepared mixture. The importance of developing quantitative methods based on the use of a reference method was thus highlighted. The method was validated according to the total error approach fixing the acceptance limits at ±15% and the α risk at ±5%. This method reaches the requirements of the European Pharmacopeia norms for the uniformity of content of single-dose preparations. The validation proves that future results will be in the acceptance limits with a previously defined probability. Finally, the in-line validated method was compared with the off-line one to demonstrate its ability to be used in routine analyses.

Establishment and reliability evaluation of the design space for HPLC analysis of six alkaloids in Coptis chinensis (Huanglian) using Bayesian approach

Coptis chinensis (Huanglian) is a commonly used traditional Chinese medicine (TCM) herb and alkaloids are the most important chemical constituents in it. In the present study, an isocratic reverse phase high performance liquid chromatography (RP-HPLC) method allowing the separation of six alkaloids in Huanglian was for the first time developed under the quality by design (QbD) principles. First, five chromatographic parameters were identified to construct a Plackett-Burman experimental design. The critical resolution, analysis time, and peak width were responses modeled by multivariate linear regression. The results showed that the percentage of acetonitrile, concentration of sodium dodecyl sulfate, and concentration of potassium phosphate monobasic were statistically significant parameters (P < 0.05). Then, the Box-Behnken experimental design was applied to further evaluate the interactions between the three parameters on selected responses. Full quadratic models were built and used to establish the analytical design space. Moreover, the reliability of design space was estimated by the Bayesian posterior predictive distribution. The optimal separation was predicted at 40% acetonitrile, 1.7 g·mL(-1) of sodium dodecyl sulfate and 0.03 mol·mL(-1) of potassium phosphate monobasic. Finally, the accuracy profile methodology was used to validate the established HPLC method. The results demonstrated that the QbD concept could be efficiently used to develop a robust RP-HPLC analytical method for Huanglian.

Surrogate matrix: opportunities and challenges for tissue sample analysis

Often there is limited availability of matching tissue matrix and/or the analyte may occur endogenously in the target tissue. Surrogate matrix provides an option for quantitation of drug, metabolite(s) and biomarker(s) in these circumstances. However, the use of a surrogate matrix also presents challenges. This paper summarizes and discusses the challenges of selecting a proper surrogate, validating the suitability of the surrogate and establishing a surrogate tissue method using the fit-for-purpose approach. This paper also systematically reviews the current practices for evaluating key parameters of a surrogate tissue assay, including sensitivity, specificity, selectivity, interference, precision, accuracy, recovery, matrix effects and stability. Considerations and suggestions are provided for dealing with such challenges during method establishment and tissue sample analysis.