John F. Kauffman

Selective melamine detection in multiple sample matrices with a portable Raman instrument using surface enhanced Raman spectroscopy-active gold nanoparticles

Melamine adulteration of food and pharmaceutical products is a major concern and there is a growing need to protect the public from exposure to contaminated or adulterated products. One approach to reduce this threat is to develop a portable method for on-site rapid testing. We describe a universal and selective method for the detection of melamine in a variety of solid matrices at the 100-200 μg L(-1) level by surface enhanced Raman spectroscopy (SERS) with gold nanoparticles. With minimal sample preparation and the use of a portable Raman spectrometer, this work will lead to field-based screening for melamine adulteration. Citrate coated gold nanoparticles (Au NPs) were investigated for both colorimetric and Raman-based responses. Several non-hazardous solvents were evaluated in order to develop a melamine extraction procedure safe for field applications. Au NP agglomerates formed by the addition of isopropanol (IPA) prior to sample introduction enhanced the Raman signal for melamine and eliminated matrix interference for substrate formation. The melamine Raman signal resulted in a 10(5) enhancement through the use of Au NP agglomerates. To our knowledge, we have developed the first portable SERS method using Au NPs to selectively screen for the presence of melamine adulteration in a variety of food and pharmaceutical matrices, including milk powder, infant formula, lactose, povidone, whey protein, wheat bran and wheat gluten.

Using a portable ion mobility spectrometer to screen dietary supplements for sibutramine

In response to recent incidents of undeclared sibutramine, an appetite suppressant found in dietary supplements, we developed a method to detect sibutramine using hand-held ion mobility spectrometers with an analysis time of 15 s. Ion mobility spectrometry is a high-throughput and sensitive technique that has been used for illicit drug, explosive, volatile organic compound and chemical warfare detection. We evaluated a hand-held ion mobility spectrometer as a tool for the analysis of supplement extracts containing sibutramine. The overall instrumental limit of detection of five portable ion mobility spectrometers was 2 ng of sibutramine HCl. When sample extractions containing 30 ng/μl or greater of sibutramine were analyzed, saturation of the ionization chamber of the spectrometer occurred and the instrument required more than three cleaning cycles to remove the drug. Hence, supplement samples suspected of containing sibutramine should be prepared at concentrations of 2-20 ng/μl. To obtain this target concentration range for products containing unknown amounts of sibutramine, we provided a simple sample preparation procedure, allowing the U.S. Food and Drug Administration or other agencies to screen products using the portable ion mobility spectrometer.

Assessment of the influence factors on in vitro testing of nasal sprays using Box-Behnken experimental design

The purpose of the research was to investigate the influences of actuation parameters and formulation physical properties on nasal spray delivery performance using design of experiment (DOE) methodology. A 3-level, 4-factor Box-Behnken design with a total of 27 experimental runs was used in this study. Nine simulated aqueous formulations with different viscosities and surface tensions were prepared using carboxymethylcellulose sodium (CMC, gelling agent) and Tween80 (surfactant) each at three concentration levels. Four factors, actuation stroke length, actuation velocity, concentration of gelling agent, and concentration of surfactant were investigated for their influences on measured responses of shot weight, spray pattern, plume geometry and droplet size distribution (DSD). The models based on data from the DOE were then optimized by eliminating insignificant terms. Pfeiffer nasal spray pump units filled with the simulated formulations were used in the study. Nasal pump actuation stroke length exerts a strong, independent influence on shot weight, and also slightly affects spray pattern and plume geometry. Actuation velocity and concentration of gelling agent have significant effects on spray pattern, plume geometry and DSD, in a complicated manner through interaction terms. Concentration of surfactant has little, if any, influence on nasal spray characteristics. Results were fitted to quadratic models describing the inherent relationships between the four factors evaluated and nasal spray performance. The DOE study helped us to identify the source of variability in nasal spray product performance, and obtained better understanding in how to control the variability. Moreover, the quadratic models developed from the DOE study quantitatively describe the inherent relationships between the factors and nasal spray performance characteristics. With the assistance of the response surfaces developed from the DOE model, the time and labor in designing a nasal spray product to achieve desired product performance characteristics can be reduced.

Qualitative screening for adulterants in weight-loss supplements by ion mobility spectrometry

Ion mobility spectrometry (IMS) served as a rapid, qualitative screening tool for the analysis of adulterated weight-loss products. We have previously shown that sibutramine extracted into methanol from dietary supplements can be detected at low levels (2ng) using a portable IMS spectrometer, and have adapted a similar method for the analysis of additional weight-loss product adulterants. An FDA collaborative study helped to define the limits for fluoxetine with a limit of detection of 2ng. We also evaluated more readily available, less toxic extraction solvents and found isopropanol and water were comparable to methanol. Isopropanol was favored over water for two reasons: (1) water increases the analysis time and (2) aqueous solutions were more susceptible to pH change, which affected the detection of sibutramine. In addition to sibutamine and fluoxetine, we surveyed 11 weight-loss adulterants; bumetanide, fenfluramine, furosemide, orlistat, phenolphthalein, phentermine, phenytoin, rimonabant, sertraline and two sibutramine analogs, desmethylsibutramine and didesmethylsibutramine, using portable and benchtop ion mobility spectrometers. Out of these 13 active pharmaceutical ingredients (APIs), portable and benchtop ion mobility spectrometers were capable of screening products for 10 of these APIs. The developed procedure was applied to two weight-loss dietary supplements using both portable and benchtop instruments. One product contained didesmethylsibutramine while the other contained didesmethylsibutramine and phenolphthalein.

Elemental Impurities in Pharmaceutical Excipients

Control of elemental impurities in pharmaceutical materials is currently undergoing a transition from control based on concentrations in components of drug products to control based on permitted daily exposures in drug products. Within the pharmaceutical community, there is uncertainty regarding the impact of these changes on manufactures of drug products. This uncertainty is fueled in part by a lack of publically available information on elemental impurity levels in common pharmaceutical excipients. This paper summarizes a recent survey of elemental impurity levels in common pharmaceutical excipients as well as some drug substances. A widely applicable analytical procedure was developed and was shown to be suitable for analysis of elements that are subject to United States Pharmacopoeia Chapter <232> and International Conference on Harmonizations Q3D Guideline on Elemental Impurities. The procedure utilizes microwave-assisted digestion of pharmaceutical materials and inductively coupled plasma mass spectrometry for quantitative analysis of these elements. The procedure was applied to 190 samples from 31 different excipients and 15 samples from eight drug substances provided through the International Pharmaceutical Excipient Council of the Americas. The results of the survey indicate that, for the materials included in the study, relatively low levels of elemental impurities are present.

Evaluation of Impaction Force of Nasal Sprays and Metered-Dose Inhalers Using the Texture Analyser☆

The impaction force from an inhalation product is an important characteristics by which to characterize the spray plume. It is one of the plume characteristics that can be perceived by a patient, and is expected to be good measures of local delivery equivalence for inhalation drugs. A Stable Micro Systems TA-XT.plus Texture Analyser equipped with 750 g load cell was used to measure the impaction force of several nasal sprays and metered-dose inhalers (MDIs). A survey of several commercial nasal spray and MDI products shows that impaction forces of these products varies from 1.5 to 6.5 g force and are significantly different from each other. A 3-level, 4-factor Box-Behnken design was applied to the study of impaction force of nasal sprays using placebo solutions. The influences of four factors: actuation stroke length, actuation velocity, concentration of gelling agent, and concentration of surfactant, were investigated. Of those factors examined here, actuation velocity exerts the greatest effect on impaction force. Impaction force is a discriminative parameter for in vitro testing of nasal spray and MDI products. Since impaction force is more directly related to patient sensation and aerosol deposition in the nasal mucus than other, more traditional parameters, it may provide a better way to evaluate in vitro equivalence in support of abbreviated new drug applications (ANDAs) for orally inhaled and nasal drug products.

Propagation of uncertainty in nasal spray in vitro performance models using Monte Carlo simulation: Part II. Error propagation during product performance modeling

Monte Carlo simulations were applied to investigate the propagation of uncertainty in both input variables and response measurements on model prediction for nasal spray product performance design of experiment (DOE) models in the first part of this study, with an initial assumption that the models perfectly represent the relationship between input variables and the measured responses. In this article, we discard the initial assumption, and extended the Monte Carlo simulation study to examine the influence of both input variable variation and product performance measurement variation on the uncertainty in DOE model coefficients. The Monte Carlo simulations presented in this article illustrate the importance of careful error propagation during product performance modeling. Our results show that the error estimates based on Monte Carlo simulation result in smaller model coefficient standard deviations than those from regression methods. This suggests that the estimated standard deviations from regression may overestimate the uncertainties in the model coefficients. Monte Carlo simulations provide a simple software solution to understand the propagation of uncertainty in complex DOE models so that design space can be specified with statistically meaningful confidence levels.

Synthesis and detection of N-sulfonated oversulfated chondroitin sulfate in marketplace heparin

N-sulfonated oversulfated chondroitin sulfate (NS-OSCS), recently reported as a potential threat to the heparin supply, was prepared along with its intermediate derivatives. All compounds were spiked into marketplace heparin and subjected to United States Pharmacopeia (USP) identification assays for heparin (proton nuclear magnetic resonance [(1)H NMR], chromatographic identity, % galactosamine [%GalN], anti-factor IIa potency, and anti-factor Xa/IIa ratio). The U.S. Food and Drug Administration (FDA) strong-anionic exchange high-performance liquid chromatography (SAX-HPLC) method resolved NS-OSCS from heparin and OSCS and had a limit of detection of 0.26% (w/w) NS-OSCS. The %GalN test was sensitive to the presence of NS-OSCS in heparin. Therefore, current USP heparin monograph tests (i.e., SAX-HPLC and %GalN) detect the presence of NS-OSCS in heparin.

Propagation of uncertainty in nasal spray in vitro performance models using Monte Carlo simulation: Part I. model prediction using Monte Carlo Simulation*

Design of experiment (DOE) methodology can provide a complete evaluation of the influences of nasal spray activation and formulation properties on delivery performance which makes it a powerful tool for product design purposes. Product performance models are computed from complex expressions containing multiple factor terms and response terms. Uncertainty in the regression model can be propagated using Monte Carlo simulation. In this study, four input factors, actuation stroke length, actuation velocity, concentration of gelling agent, and concentration of surfactant were investigated for their influences on measured responses of spray pattern, plume width, droplet size distribution (DSD), and impaction force. Quadratic models were calculated and optimized using a Box-Behnken experimental design to describe the relationship between factors and responses. Assuming that the models perfectly represent the relationship between input variables and the measured responses, the propagation of uncertainty in both input variables and response measurements on model prediction was performed using Monte Carlo simulations. The Monte Carlo simulations presented in this article illustrate the propagation of uncertainty in model predictions. The most influential input variable variances on the product performance variance were identified, which could help prioritize input variables in terms of importance during continuous improvement of nasal spray product design. This work extends recent Monte Carlo simulations of process models to the realm of product development models.