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Customized pharmaceutical products aim to comply with the individual needs of a patient to enhance the treatment outcome. The current pharmaceutical production paradigm is, however, dominated by mass production, where the pharmaceutical products embrace a one-size-fits-all design with a low possibility of treatment optimization to patient needs. This production paradigm is not designed or intended for customized pharmaceutical products and operating this production context for customized pharmaceutical products is argued to be cost-inefficient. To address this challenge of inefficient production of customized pharmaceutical products, this study proposes an approach to modular pharmaceutical product design. As a mass customization strategy, product modularization enables serving customers with customized products cost-efficiently. The proposed modular pharmaceutical products integrate three product design requirements originating from patient needs: a scalable dose strength, a flexible target release profile, and a scalable treatment size. An approach to assess the value of these product designs is presented, by means of proposing three benefit metrics complying with respective design requirements and a cost metric assessing the cost of producing these modular pharmaceutical product designs. Results suggest that pharmaceutical product modularization can, by keeping the number of produced components low, substantially increase the external product variety and, hence, enhance the treatment outcome of patients. Furthermore, results indicate that the achieved benefit for the patient through product modularization increases beyond additional costs arising during production. However, a careful modularization must be performed to optimize the tradeoff between the increased benefit and cost.
Maria Siiskonen; Johan Malmqvist; Staffan Folestad. Pharmaceutical Product Modularization as a Mass Customization Strategy to Increase Patient Benefit Cost-Efficiently. Systems 2021, 9, 59 .
AMA StyleMaria Siiskonen, Johan Malmqvist, Staffan Folestad. Pharmaceutical Product Modularization as a Mass Customization Strategy to Increase Patient Benefit Cost-Efficiently. Systems. 2021; 9 (3):59.
Chicago/Turabian StyleMaria Siiskonen; Johan Malmqvist; Staffan Folestad. 2021. "Pharmaceutical Product Modularization as a Mass Customization Strategy to Increase Patient Benefit Cost-Efficiently." Systems 9, no. 3: 59.
Ideal controlled pulmonary drug delivery systems provide sustained release by retarding lung clearance mechanisms and efficient lung deposition to maintain therapeutic concentrations over prolonged time. Here, we use atomic layer deposition (ALD) to simultaneously tailor the release and aerosolization properties of inhaled drug particles without the need for lactose carrier. In particular, we deposit uniform nanoscale oxide ceramic films, such as Al2O3, TiO2, and SiO2, on micronized budesonide particles, a common active pharmaceutical ingredient for the treatment of respiratory diseases. In vitro dissolution and ex vivo isolated perfused rat lung tests demonstrate dramatically slowed release with increasing nanofilm thickness, regardless of the nature of the material. Ex situ transmission electron microscopy at various stages during dissolution unravels mostly intact nanofilms, suggesting that the release mechanism mainly involves the transport of dissolution media through the ALD films. Furthermore, in vitro aerosolization testing by fast screening impactor shows a ∼2-fold increase in fine particle fraction (FPF) for each ALD-coated budesonide formulation after 10 ALD process cycles, also applying very low patient inspiratory pressures. The higher FPFs after the ALD process are attributed to the reduction in the interparticle force arising from the ceramic surfaces, as evidenced by atomic force microscopy measurements. Finally, cell viability, cytokine release, and tissue morphology analyses verify a safe and efficacious use of ALD-coated budesonide particles at the cellular level. Therefore, surface nanoengineering by ALD is highly promising in providing the next generation of inhaled formulations with tailored characteristics of drug release and lung deposition, thereby enhancing controlled pulmonary delivery opportunities.
Damiano La Zara; Feilong Sun; Fuweng Zhang; Frans Franek; Kinga Balogh Sivars; Jenny Horndahl; Stephanie Bates; Marie Brännström; Pär Ewing; Michael J. Quayle; Gunilla Petersson; Staffan Folestad; J. Ruud van Ommen. Controlled Pulmonary Delivery of Carrier-Free Budesonide Dry Powder by Atomic Layer Deposition. ACS Nano 2021, 15, 6684 -6698.
AMA StyleDamiano La Zara, Feilong Sun, Fuweng Zhang, Frans Franek, Kinga Balogh Sivars, Jenny Horndahl, Stephanie Bates, Marie Brännström, Pär Ewing, Michael J. Quayle, Gunilla Petersson, Staffan Folestad, J. Ruud van Ommen. Controlled Pulmonary Delivery of Carrier-Free Budesonide Dry Powder by Atomic Layer Deposition. ACS Nano. 2021; 15 (4):6684-6698.
Chicago/Turabian StyleDamiano La Zara; Feilong Sun; Fuweng Zhang; Frans Franek; Kinga Balogh Sivars; Jenny Horndahl; Stephanie Bates; Marie Brännström; Pär Ewing; Michael J. Quayle; Gunilla Petersson; Staffan Folestad; J. Ruud van Ommen. 2021. "Controlled Pulmonary Delivery of Carrier-Free Budesonide Dry Powder by Atomic Layer Deposition." ACS Nano 15, no. 4: 6684-6698.
Independent individualization of multiple product attributes, such as dose and drug release, is a crucial overarching requirement of pharmaceutical products for individualized therapy as is the unified integration of individualized product design with the processes and production that drive patient access to such therapy. Individualization intrinsically demands a marked increase in the number of product variants to suit smaller, more stratified patient populations. One established design strategy to provide enhanced product variety is product modularization. Despite existing customized and/or modular product design concepts, multifunctional individualization in an integrated manner is still strikingly absent in pharma. Consequently, this study aims to demonstrate multifunctional individualization through a modular product design capable of providing an increased variety of release profiles independent of dose and dosage form size. To further exhibit that increased product variety is attainable even with a low degree of product modularity, the modular design was based upon a fixed target dosage form size of approximately 200 mm3 comprising two modules, approximately 100 mm3 each. Each module contained a melt-extruded and molded formulation of 40% w/w metoprolol succinate in a PEG1500 and Kollidon® VA64 erodible hydrophilic matrix surrounded by polylactic acid and/or polyvinyl acetate as additional release rate-controlling polymers. Drug release testing confirmed the generation of predictable, combined drug release kinetics for dosage forms, independent of dose, based on a product’s constituent modules and enhanced product variety through a minimum of six dosage form release profiles from only three module variants. Based on these initial results, the potential of the reconfigurable modular product design concept is discussed for unified integration into a pharmaceutical mass customization/mass personalization context.
Rydvikha Govender; Susanna Abrahmsén-Alami; Anette Larsson; Anders Borde; Alexander Liljeblad; Staffan Folestad. Independent Tailoring of Dose and Drug Release via a Modularized Product Design Concept for Mass Customization. Pharmaceutics 2020, 12, 771 .
AMA StyleRydvikha Govender, Susanna Abrahmsén-Alami, Anette Larsson, Anders Borde, Alexander Liljeblad, Staffan Folestad. Independent Tailoring of Dose and Drug Release via a Modularized Product Design Concept for Mass Customization. Pharmaceutics. 2020; 12 (8):771.
Chicago/Turabian StyleRydvikha Govender; Susanna Abrahmsén-Alami; Anette Larsson; Anders Borde; Alexander Liljeblad; Staffan Folestad. 2020. "Independent Tailoring of Dose and Drug Release via a Modularized Product Design Concept for Mass Customization." Pharmaceutics 12, no. 8: 771.
Damiano La Zara; Maximilian R. Bailey; Peter-Leon Hagedoorn; Dominik Benz; Michael J. Quayle; Staffan Folestad; J. Ruud Van Ommen. Sub-nanoscale Surface Engineering of TiO2 Nanoparticles by Molecular Layer Deposition of Poly(ethylene terephthalate) for Suppressing Photoactivity and Enhancing Dispersibility. ACS Applied Nano Materials 2020, 3, 6737 -6748.
AMA StyleDamiano La Zara, Maximilian R. Bailey, Peter-Leon Hagedoorn, Dominik Benz, Michael J. Quayle, Staffan Folestad, J. Ruud Van Ommen. Sub-nanoscale Surface Engineering of TiO2 Nanoparticles by Molecular Layer Deposition of Poly(ethylene terephthalate) for Suppressing Photoactivity and Enhancing Dispersibility. ACS Applied Nano Materials. 2020; 3 (7):6737-6748.
Chicago/Turabian StyleDamiano La Zara; Maximilian R. Bailey; Peter-Leon Hagedoorn; Dominik Benz; Michael J. Quayle; Staffan Folestad; J. Ruud Van Ommen. 2020. "Sub-nanoscale Surface Engineering of TiO2 Nanoparticles by Molecular Layer Deposition of Poly(ethylene terephthalate) for Suppressing Photoactivity and Enhancing Dispersibility." ACS Applied Nano Materials 3, no. 7: 6737-6748.
Individualized therapy with pharmaceutical products aims to elicit predictable and optimized treatment responses from specific patients. Doing so requires production platforms and technology capable of tailoring products to individual patient needs. However, despite recent manufacturing innovations and key technologies on the rise, e.g. continuous manufacturing and additive manufacturing (3D printing), the prevailing production paradigm employed in the pharmaceutical industry is mass production. Although mass production is efficient and cost-effective, it is typically based on a ‘one-size-fits-all’ product concept and lacks the flexibility and agility required to fully meet the needs of the individual patient. Indeed, we present data that confirm a suspected major imbalance between the recent medical evolution underpinning personalized/precision medicine and the recent advances in the associated manufacturing technologies. In this context we target the needs of the individual as a main driver for pharmaceutical products which support individualized therapy. We particularly address that a wider integration of critical patient dimensions into the manufacture and provision of pharmaceutical products is pivotal for enabling a patient-centric and efficient mass customization-based production paradigm. Here, we present a critical review of the area and its inherent challenges which aims to clarify key design requirements for establishing mass customization opportunities. Through primary sources of scientific information for individualized therapies, patient needs are captured, analysed, and conceptualized. This summarized set of key drivers provides the basis for a proposed patient-centric framework of requirements for use in design of product and production platforms for mass customization. The extent to which emerging pharmaceutical manufacturing technologies satisfy key individual patient needs is explored through a high-level assessment against the proposed patient-centric framework, with special attention paid to oral dosage forms. Altogether this holistic review and position paper, with its constituent steps, reveals major gaps in the evolution of Product-Process-Production approaches and solutions required for producing affordable individualized/personalized pharmaceuticals that respond to the needs and demands of the individual patient. Lastly, in a brief commentary and outlook, we suggest key research directions for closing gaps and addressing manufacturing technology challenges. We also articulate the importance of tackling them in a holistic, integrated way, together with challenges in product individualization and personalization.
Rydvikha Govender; Susanna Abrahmsén-Alami; Anette Larsson; Staffan Folestad. Therapy for the individual: Towards patient integration into the manufacturing and provision of pharmaceuticals. European Journal of Pharmaceutics and Biopharmaceutics 2020, 149, 58 -76.
AMA StyleRydvikha Govender, Susanna Abrahmsén-Alami, Anette Larsson, Staffan Folestad. Therapy for the individual: Towards patient integration into the manufacturing and provision of pharmaceuticals. European Journal of Pharmaceutics and Biopharmaceutics. 2020; 149 ():58-76.
Chicago/Turabian StyleRydvikha Govender; Susanna Abrahmsén-Alami; Anette Larsson; Staffan Folestad. 2020. "Therapy for the individual: Towards patient integration into the manufacturing and provision of pharmaceuticals." European Journal of Pharmaceutics and Biopharmaceutics 149, no. : 58-76.
In this work, we report molecular layer deposition (MLD) of ultrathin poly(ethylene terephthalate) (PET) films on gram-scale batches of ultrafine particles for the first time. TiO2 P25 nanoparticles (NPs) are coated up to 50 cycles in an atmospheric-pressure fluidized bed reactor at 150 °C using terephthaloyl chloride and ethylene glycol as precursors. Ex-situ diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis and transmission electron microscopy show the linear growth at 0.05 nm/cycle of uniform and conformal PET films, which are unattainable with conventional wet-phase approaches. The subnano and nano PET films not only suppress the photocatalytic activity of TiO2 NPs by reducing the generation of hydroxyl radicals, but also improve the dispersibility of TiO2 NPs in both organic and aqueous media. Still, the bulk optical properties, electronic structure and surface area of TiO2 are essentially unaffected by the MLD process. This study demonstrates the industrial relevance of MLD to simultaneously tune the photoactivity and dispersibility of the commercial photocatalyst TiO2 P25. Moreover, by rapidly modifying the surface properties of particles in a controlled manner at the subnanometer scale, particle MLD can serve many applications ranging from nanofluids to emulsions to polymer nanocomposites.
Damiano La Zara; Maximilian R. Bailey; Peter-Leon Hagedoorn; Dominik Benz; Michael J. Quayle; Staffan Folestad; J. Ruud Van Ommen. Subnano Surface Engineering of TiO2 Nanoparticles by PET Molecular Layer Deposition: Tuning Photoactivity and Dispersibility. 2019, 1 .
AMA StyleDamiano La Zara, Maximilian R. Bailey, Peter-Leon Hagedoorn, Dominik Benz, Michael J. Quayle, Staffan Folestad, J. Ruud Van Ommen. Subnano Surface Engineering of TiO2 Nanoparticles by PET Molecular Layer Deposition: Tuning Photoactivity and Dispersibility. . 2019; ():1.
Chicago/Turabian StyleDamiano La Zara; Maximilian R. Bailey; Peter-Leon Hagedoorn; Dominik Benz; Michael J. Quayle; Staffan Folestad; J. Ruud Van Ommen. 2019. "Subnano Surface Engineering of TiO2 Nanoparticles by PET Molecular Layer Deposition: Tuning Photoactivity and Dispersibility." , no. : 1.
In this work, we report molecular layer deposition (MLD) of ultrathin poly(ethylene terephthalate) (PET) films on gram-scale batches of ultrafine particles for the first time. TiO2 P25 nanoparticles (NPs) are coated up to 50 cycles in an atmospheric-pressure fluidized bed reactor at 150 °C using terephthaloyl chloride and ethylene glycol as precursors. Ex-situ diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis and transmission electron microscopy show the linear growth at 0.05 nm/cycle of uniform and conformal PET films, which are unattainable with conventional wet-phase approaches. The subnano and nano PET films not only suppress the photocatalytic activity of TiO2 NPs by reducing the generation of hydroxyl radicals, but also improve the dispersibility of TiO2 NPs in both organic and aqueous media. Still, the bulk optical properties, electronic structure and surface area of TiO2 are essentially unaffected by the MLD process. This study demonstrates the industrial relevance of MLD to simultaneously tune the photoactivity and dispersibility of the commercial photocatalyst TiO2 P25. Moreover, by rapidly modifying the surface properties of particles in a controlled manner at the subnanometer scale, particle MLD can serve many applications ranging from nanofluids to emulsions to polymer nanocomposites.
Damiano La Zara; Maximilian R. Bailey; Peter-Leon Hagedoorn; Dominik Benz; Michael J. Quayle; Staffan Folestad; J. Ruud Van Ommen. Subnano Surface Engineering of TiO2 Nanoparticles by PET Molecular Layer Deposition: Tuning Photoactivity and Dispersibility. 2019, 1 .
AMA StyleDamiano La Zara, Maximilian R. Bailey, Peter-Leon Hagedoorn, Dominik Benz, Michael J. Quayle, Staffan Folestad, J. Ruud Van Ommen. Subnano Surface Engineering of TiO2 Nanoparticles by PET Molecular Layer Deposition: Tuning Photoactivity and Dispersibility. . 2019; ():1.
Chicago/Turabian StyleDamiano La Zara; Maximilian R. Bailey; Peter-Leon Hagedoorn; Dominik Benz; Michael J. Quayle; Staffan Folestad; J. Ruud Van Ommen. 2019. "Subnano Surface Engineering of TiO2 Nanoparticles by PET Molecular Layer Deposition: Tuning Photoactivity and Dispersibility." , no. : 1.
Acoustic Emission (AE) measurement technology has gained wide appreciation in material sciences and process monitoring. In inhalation research, AE has been used for adherence indicating applications in clinical studies. Promising results from feasibility studies using AE combined with multivariate data analysis (AE-MVDA) in the analysis of devices for inhalation have prompted a broader study reported in this paper. This work presents the novel application of AE-MVDA for assessment of the combined inhalation device and formulation performance. The purpose is to evaluate the benefits that this technology can provide to inhalation product development programs. The work was carried out using two different dry powder inhaler device model systems while investigating different performance features. The devices were filled with dry powder formulations with both placebo and with active pharmaceutical ingredient (API). The acquired AE data was analyzed using multivariate data analysis tools such as Principal component analysis (PCA) and orthogonal projections to latent structures (OPLS). The AE profiles were indicative for device and formulation performance. Normal and deviating performances were readily picked up in the AE data. Moreover, performance trends between doses withdrawn from the inhalers were also observable. Lastly, differences in the AE profile between the formulations could be detected. The overall conclusion from the AE-MVDA measurement approach evaluation is that it has the potential to add value as a cost-effective, non-invasive quality and performance monitoring technology both in development and in production of inhaled medicines.
Mikael Boberg; Lisa Holmstén; Mats Josefson; Roland Greguletz; Kyrre Thalberg; Staffan Folestad; Lars Karlsson. Characterization of acoustic emission analysis in applications for inhalation device performance assessment. International Journal of Pharmaceutics 2019, 563, 304 -313.
AMA StyleMikael Boberg, Lisa Holmstén, Mats Josefson, Roland Greguletz, Kyrre Thalberg, Staffan Folestad, Lars Karlsson. Characterization of acoustic emission analysis in applications for inhalation device performance assessment. International Journal of Pharmaceutics. 2019; 563 ():304-313.
Chicago/Turabian StyleMikael Boberg; Lisa Holmstén; Mats Josefson; Roland Greguletz; Kyrre Thalberg; Staffan Folestad; Lars Karlsson. 2019. "Characterization of acoustic emission analysis in applications for inhalation device performance assessment." International Journal of Pharmaceutics 563, no. : 304-313.
The morphology, size and surface properties of pharmaceutical particles form an essential role in the therapeutic performance of active pharmaceutical ingredients (APIs) and excipients as constituents in various drug delivery systems and clinical applications. Recent advances in methods for surface modification, however, rely heavily on liquid-phase based modification processes and afford limited control over the thickness and conformality of the coating. Atomic layer deposition (ALD), on the other hand, enables the formation of conformal nanoscale films on complex structures with thickness control on the molecular level, whilst maintaining the substrate particle size and morphology. Moreover, this enables nanoengineering of surfaces of pharmaceutical particles also in the dry state. Successful nano-engineeering of crystal and amorphous surfaces of pharmaceutical particles is demonstrated in this study whereby functional properties, such as dissolution and dispersability, were tailored for drug delivery applications. This expands on our initial work on ALD of alumina on pharmaceutical particles within the lower micro- to higher nano-size ranges to here probe both crystalline and amorphous lactose substrate surfaces (d50 3.5 and 21 um). In addition, both water and ozone co-reactants were evaluated; the latter having not been evaluated previously for pharmaceutical particles. The deposition process is carried out at ambient conditions in a fluidized bed reactor for a low number of cycles (i.e. from 4 to14). Improved dissolution and extended release were achieved by the ALD nanoengineering of both crystalline and amorphous surfaces. This novel concept opens up exciting opportunities to produce more complex materials and structures using temperature and moisture sensitive drugs, e.g. targeting and drug delivery opportunities, as well as delivering new functionalities for novel applications in the pharmaceutical, medical, biological, and advanced materials fields. The prospects for advancing inhaled drug delivery are exemplified by the ALD surface nano-engineering concept.
Di Zhang; Damiano La Zara; Michael J. Quayle; Gunilla Petersson; J. Ruud van Ommen; Staffan Folestad. Nanoengineering of Crystal and Amorphous Surfaces of Pharmaceutical Particles for Biomedical Applications. ACS Applied Bio Materials 2019, 2, 1518 -1530.
AMA StyleDi Zhang, Damiano La Zara, Michael J. Quayle, Gunilla Petersson, J. Ruud van Ommen, Staffan Folestad. Nanoengineering of Crystal and Amorphous Surfaces of Pharmaceutical Particles for Biomedical Applications. ACS Applied Bio Materials. 2019; 2 (4):1518-1530.
Chicago/Turabian StyleDi Zhang; Damiano La Zara; Michael J. Quayle; Gunilla Petersson; J. Ruud van Ommen; Staffan Folestad. 2019. "Nanoengineering of Crystal and Amorphous Surfaces of Pharmaceutical Particles for Biomedical Applications." ACS Applied Bio Materials 2, no. 4: 1518-1530.
Atomic layer deposition on pharmaceutical particles for drug delivery applications is demonstrated using assisted fluidized bed dry powder processing. Complete and conformal layering is achieved on particle sizes from the lower micron to upper nanometer range under near ambient conditions. As few as 2–14 atomic alumina layers alter particle properties: dissolution, dispersibility and heat transfer.
D. Zhang; M. J. Quayle; G. Petersson; J. R. Van Ommen; S. Folestad. Atomic scale surface engineering of micro- to nano-sized pharmaceutical particles for drug delivery applications. Nanoscale 2017, 9, 11410 -11417.
AMA StyleD. Zhang, M. J. Quayle, G. Petersson, J. R. Van Ommen, S. Folestad. Atomic scale surface engineering of micro- to nano-sized pharmaceutical particles for drug delivery applications. Nanoscale. 2017; 9 (32):11410-11417.
Chicago/Turabian StyleD. Zhang; M. J. Quayle; G. Petersson; J. R. Van Ommen; S. Folestad. 2017. "Atomic scale surface engineering of micro- to nano-sized pharmaceutical particles for drug delivery applications." Nanoscale 9, no. 32: 11410-11417.
An overview of the role and use of Raman spectroscopy for advanced process measurements is presented. Special emphasis is given to the potential of Raman spectroscopy as a tool for assessment, monitoring and advanced control of chemical content and crystallinity/polymorphism during pharmaceutical processing. As a Process Analytical Technology (PAT) tool, Raman spectroscopy can add value to both product/process development and to manufacturing processing. The wide range of PAT examples that are reviewed in this chapter emanates from emerging applications in primary and secondary manufacturing processing and in bioprocessing. In addition, strategies and the special requirements on Raman instrumentation for PAT are discussed.
Jonas Johansson; Mike Claybourn; Staffan Folestad. Raman Spectroscopy: A Strategic Tool in the Process Analytical Technology Toolbox. Laser-Tissue Interactions 2009, 241 -262.
AMA StyleJonas Johansson, Mike Claybourn, Staffan Folestad. Raman Spectroscopy: A Strategic Tool in the Process Analytical Technology Toolbox. Laser-Tissue Interactions. 2009; ():241-262.
Chicago/Turabian StyleJonas Johansson; Mike Claybourn; Staffan Folestad. 2009. "Raman Spectroscopy: A Strategic Tool in the Process Analytical Technology Toolbox." Laser-Tissue Interactions , no. : 241-262.
Photontime-of-flight spectroscopy (PTOFS) is a powerful tool for analysis of turbid materials. We have constructed a time-of-flight spectrometer based on a supercontinuum fiber laser, acousto-optical tunable filtering, and an InP/InGaAsP microchannel plate photomultiplier tube. The system is capable of performing PTOFS up to 1400 nm, and thus covers an important region for vibrational spectroscopy of solid samples. The development significantly increases the applicability of PTOFS for analysis of chemical content and physical properties of turbid media. The great value of the proposed approach is illustrated by revealing the distinct absorption features of turbid epoxy resin. Promising future applications of the approach are discussed, including quantitative assessment of pharmaceuticals, powder analysis, and calibration-free near-infrared spectroscopy.
Tomas Svensson; Erik Alerstam; Dmitry Khoptyar; Jonas Johansson; Staffan Folestad; Stefan Andersson-Engels. Near-infrared photon time-of-flight spectroscopy of turbid materials up to 1400 nm. Review of Scientific Instruments 2009, 80, 063105 .
AMA StyleTomas Svensson, Erik Alerstam, Dmitry Khoptyar, Jonas Johansson, Staffan Folestad, Stefan Andersson-Engels. Near-infrared photon time-of-flight spectroscopy of turbid materials up to 1400 nm. Review of Scientific Instruments. 2009; 80 (6):063105.
Chicago/Turabian StyleTomas Svensson; Erik Alerstam; Dmitry Khoptyar; Jonas Johansson; Staffan Folestad; Stefan Andersson-Engels. 2009. "Near-infrared photon time-of-flight spectroscopy of turbid materials up to 1400 nm." Review of Scientific Instruments 80, no. 6: 063105.
We present significant advances in high-resolution spectroscopy for characterization of turbid and porous materials. In particular, we focus on its use for structural analysis of pharmaceutical materials, and the implementation of optical porosimetry.
Tomas Svensson; Stefan Andersson-Engels; Jonas Johansson; Staffan Folestad. Laser Spectroscopy for Assessing Structural Properties of Turbid Solids: Towards Optical Porosimetry. Laser Applications to Chemical, Security and Environmental Analysis 2008, 1 .
AMA StyleTomas Svensson, Stefan Andersson-Engels, Jonas Johansson, Staffan Folestad. Laser Spectroscopy for Assessing Structural Properties of Turbid Solids: Towards Optical Porosimetry. Laser Applications to Chemical, Security and Environmental Analysis. 2008; ():1.
Chicago/Turabian StyleTomas Svensson; Stefan Andersson-Engels; Jonas Johansson; Staffan Folestad. 2008. "Laser Spectroscopy for Assessing Structural Properties of Turbid Solids: Towards Optical Porosimetry." Laser Applications to Chemical, Security and Environmental Analysis , no. : 1.
Tomas Svensson; Linda Persson; Mats Andersson; Sune Svanberg; Stefan Andersson-Engels; Jonas Johansson; Staffan Folestad. Noninvasive Characterization of Pharmaceutical Solids by Diode Laser Oxygen Spectroscopy. Applied Spectroscopy 2007, 61, 784 -786.
AMA StyleTomas Svensson, Linda Persson, Mats Andersson, Sune Svanberg, Stefan Andersson-Engels, Jonas Johansson, Staffan Folestad. Noninvasive Characterization of Pharmaceutical Solids by Diode Laser Oxygen Spectroscopy. Applied Spectroscopy. 2007; 61 (7):784-786.
Chicago/Turabian StyleTomas Svensson; Linda Persson; Mats Andersson; Sune Svanberg; Stefan Andersson-Engels; Jonas Johansson; Staffan Folestad. 2007. "Noninvasive Characterization of Pharmaceutical Solids by Diode Laser Oxygen Spectroscopy." Applied Spectroscopy 61, no. 7: 784-786.
The scope of this work is a new methodology to correct conventional near-infrared (NIR) data for scattering effects. The technique aims at measuring the absorption coefficient of the samples rather than the total attenuation measured in conventional NIR spectroscopy. The main advantage of this is that the absorption coefficient is independent of the path length of the light inside the sample and therefore independent of the scattering effects. The method is based on time-resolved spectroscopy and modeling of light transport by diffusion theory. This provides an independent measure of the scattering properties of the samples and therefore of the path length of light. This yields a clear advantage over other preprocessing techniques, where scattering effects are estimated and corrected for by using the shape of the measured spectrum only. Partial least squares (PLS) calibration models show that, by using the proposed evaluation scheme, the predictive ability is improved by 50% as compared to a model based on conventional NIR data alone. The method also makes it possible to predict the concentration of active substance in samples with other physical properties than the samples included in the calibration model.
Christoffer Abrahamsson; Alexandra Löwgren; Birgitta Strömdahl; Tomas Svensson; Stefan Andersson-Engels; Jonas Johansson; Staffan Folestad. Scatter Correction of Transmission Near-Infrared Spectra by Photon Migration Data: Quantitative Analysis of Solids. Applied Spectroscopy 2005, 59, 1381 -1387.
AMA StyleChristoffer Abrahamsson, Alexandra Löwgren, Birgitta Strömdahl, Tomas Svensson, Stefan Andersson-Engels, Jonas Johansson, Staffan Folestad. Scatter Correction of Transmission Near-Infrared Spectra by Photon Migration Data: Quantitative Analysis of Solids. Applied Spectroscopy. 2005; 59 (11):1381-1387.
Chicago/Turabian StyleChristoffer Abrahamsson; Alexandra Löwgren; Birgitta Strömdahl; Tomas Svensson; Stefan Andersson-Engels; Jonas Johansson; Staffan Folestad. 2005. "Scatter Correction of Transmission Near-Infrared Spectra by Photon Migration Data: Quantitative Analysis of Solids." Applied Spectroscopy 59, no. 11: 1381-1387.
The utility of capillary electrophoresis (CE) for determination of the negative logarithm of dissociation constants (pKa) of labile compounds was investigated. In this study pyridinyl–methyl–sulfinyl–benzimidazoles (PMSB's), which have both an acidic and a basic pKa, were selected as a first set of model drug compounds. This is a group of compounds that are known to degrade in aqueous solutions under neutral and acidic conditions which thus may impair their pKa determination when using common batch techniques based on spectrophotometry or potentiometry. An additional set of model drug compounds, benzenesulfonic acid phenethyloxy–phenyl esters (BSAP's), which are labile at high pH, were also studied. It is demonstrated that pKa values can be determined with high precision and accuracy by CE for both these sets of model compounds because decomposition products and impurities can be sufficiently separated from the main component. Based on the results in this study, a general strategy is proposed and discussed for determination of pKa for labile compounds. Key steps comprise use of a stabilizing sample diluent, injection by electromigration, short analysis time, and characterization of the main component by UV–Vis spectra.
Eivor Örnskov; Anna Linusson; Staffan Folestad. Determination of dissociation constants of labile drug compounds by capillary electrophoresis. Journal of Pharmaceutical and Biomedical Analysis 2003, 33, 379 -391.
AMA StyleEivor Örnskov, Anna Linusson, Staffan Folestad. Determination of dissociation constants of labile drug compounds by capillary electrophoresis. Journal of Pharmaceutical and Biomedical Analysis. 2003; 33 (3):379-391.
Chicago/Turabian StyleEivor Örnskov; Anna Linusson; Staffan Folestad. 2003. "Determination of dissociation constants of labile drug compounds by capillary electrophoresis." Journal of Pharmaceutical and Biomedical Analysis 33, no. 3: 379-391.
Time-resolved spectroscopy in the visible and near-infrared (NIR) regions was used in a feasibility study for analysis of solid pharmaceuticals. The objective of the experiments was to study the interaction of light with pharmaceutical solids and to investigate the usefulness of the method as an analytical tool for spectroscopic analysis. In these experiments, a pulsed Ti:sapphire laser and white light generation in water was utilized to form a pulsed light source in the visible/NIR region. The light was focused onto the surface of tablets, and the transmitted light was detected by a time-resolving streak camera. Two types of measurements were performed. First, a spectrometer was put in front of the streak camera for spectral resolution. Secondly, the signal originating from different locations of the sample was collected. Time-resolved and wavelength/spatially resolved data were generated and compared for a number of different samples. The most striking result from the experiments is that the typical optical path length through a 3.5-mm-thick tablet is about 20–25 cm. This indicates very strong multiple scattering in these samples. Monte Carlo simulations and comparison with experimental data support very high scattering coefficients on the order of 500 cm−1. Furthermore, the data evaluation shows that photons with a particular propagation time through the sample contain a higher chemical contrast than other propagation times or than steady-state information. In conclusion, time-resolved NIR spectroscopy yields more information about solid pharmaceutical samples than conventional steady-state spectroscopy.
Jonas Johansson; Staffan Folestad; Mats Josefson; Anders Sparén; Christoffer Abrahamsson; Stefan Andersson-Engels; Sune Svanberg. Time-Resolved NIR/Vis Spectroscopy for Analysis of Solids: Pharmaceutical Tablets. Applied Spectroscopy 2002, 56, 725 -731.
AMA StyleJonas Johansson, Staffan Folestad, Mats Josefson, Anders Sparén, Christoffer Abrahamsson, Stefan Andersson-Engels, Sune Svanberg. Time-Resolved NIR/Vis Spectroscopy for Analysis of Solids: Pharmaceutical Tablets. Applied Spectroscopy. 2002; 56 (6):725-731.
Chicago/Turabian StyleJonas Johansson; Staffan Folestad; Mats Josefson; Anders Sparén; Christoffer Abrahamsson; Stefan Andersson-Engels; Sune Svanberg. 2002. "Time-Resolved NIR/Vis Spectroscopy for Analysis of Solids: Pharmaceutical Tablets." Applied Spectroscopy 56, no. 6: 725-731.
Transmission geometry is becoming an alternative to the conventional reflectance geometry in near-infrared (NIR) spectroscopy of pharmaceuticals. An advantage of transmission NIR is that it samples a volume whereas reflectance NIR merely samples the surface region of solid preparations. This leads to more representative measurements on complex matrices, such as some types of tablets. However, more attention must be paid to sample presentation with respect to light leakage. An investigation of the effects of the light leakage obtained with different sample holder geometries on content calibrations for transmission NIR on tablets was performed. Two different model samples, a composite and a compact tablet, were measured in sample wells in which the diameters and heights were varied according to a multivariate design. This was done in order to simulate a mismatch between the tablet and the sample well. Partial least-squares (PLS) models were built and used to evaluate the significance of the sample well geometry. Liquid chromatography was used as a reference method. As expected, for both types of tablets it was found that a small mismatch in tablet-to-well diameter deteriorated the repeatability of the NIR spectra, although, unexpectedly, this gave the best predictions and more robust models. In all, this indicates that light leakage should not be minimized at calibration, but included as a factor in the multivariate model that spans the future expected variation in light leakage.
Anders Sparen; Mattias Malm; Mats Josefson; Staffan Folestad; Jonas Johansson. Light Leakage Effects with Different Sample Holder Geometries in Quantitative Near-Infrared Transmission Spectroscopy of Pharmaceutical Tablets. Applied Spectroscopy 2002, 56, 586 -592.
AMA StyleAnders Sparen, Mattias Malm, Mats Josefson, Staffan Folestad, Jonas Johansson. Light Leakage Effects with Different Sample Holder Geometries in Quantitative Near-Infrared Transmission Spectroscopy of Pharmaceutical Tablets. Applied Spectroscopy. 2002; 56 (5):586-592.
Chicago/Turabian StyleAnders Sparen; Mattias Malm; Mats Josefson; Staffan Folestad; Jonas Johansson. 2002. "Light Leakage Effects with Different Sample Holder Geometries in Quantitative Near-Infrared Transmission Spectroscopy of Pharmaceutical Tablets." Applied Spectroscopy 56, no. 5: 586-592.