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Guidetti M, Hilfiker R, Kuentz M, Bauer-Brandl A, Blatter F. Water-mediated phase transformations of posaconazole: An intricate jungle of crystal forms. Eur J Pharm Sci 2024; 195:106722. [PMID: 38336250 DOI: 10.1016/j.ejps.2024.106722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/20/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Posaconazole is a broad-spectrum antifungal agent exhibiting rich polymorphism. Up to now, a total of fourteen different crystal forms have been reported, sometimes with an ambiguous nomenclature, but less is known about their properties and stability relationships. Investigating the solid-state of a drug compound is essential to identify the most stable form under working conditions and to prevent the risk of undesired solid-phase transformations under processing and storage. In this paper, we study posaconazole polymorphism by providing a description of its polymorphs, hydrates, and solvates. Powder X-ray diffraction (PXRD), dynamic vapor sorption (DVS), spectroscopic and thermal techniques were employed to characterize the different forms. In addition, the solid-phase transformations of posaconazole in aqueous suspensions were studied by means of Raman microscopy. Surprisingly, we found that Form S, the crystal form contained in the marketed oral suspension, is not the most stable form in water. Form S readily converts to a more stable hydrate, i.e. Form A, after storage in water for two weeks. In the commercial oral formulation the conversion between the two forms is prevented by the presence of polysorbate 80. Such insights into the stabilizing excipient effects beyond particle dispersion are critical to formulators.
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Affiliation(s)
- Matteo Guidetti
- Solvias AG, Solid-State Development Department, Römerpark 2, Kaiseraugst CH- 4303, Switzerland; Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, Odense 5230, Denmark
| | - Rolf Hilfiker
- Solvias AG, Solid-State Development Department, Römerpark 2, Kaiseraugst CH- 4303, Switzerland
| | - Martin Kuentz
- University of Applied Sciences and Arts Northwestern Switzerland, Institute of Pharma Technology, Muttenz CH- 4132, Switzerland
| | - Annette Bauer-Brandl
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, Odense 5230, Denmark
| | - Fritz Blatter
- Solvias AG, Solid-State Development Department, Römerpark 2, Kaiseraugst CH- 4303, Switzerland.
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Guidetti M, Hilfiker R, Kuentz M, Bauer-Brandl A, Blatter F. Exploring the Cocrystal Landscape of Posaconazole by Combining High-Throughput Screening Experimentation with Computational Chemistry. Cryst Growth Des 2023; 23:842-852. [PMID: 36747574 PMCID: PMC9896487 DOI: 10.1021/acs.cgd.2c01072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/05/2022] [Indexed: 06/18/2023]
Abstract
The development of multicomponent crystal forms, such as cocrystals, represents a means to enhance the dissolution and absorption properties of poorly water-soluble drug compounds. However, the successful discovery of new pharmaceutical cocrystals remains a time- and resource-consuming process. This study proposes the use of a combined computational-experimental high-throughput approach as a tool to accelerate and improve the efficiency of cocrystal screening exemplified by posaconazole. First, we employed the COSMOquick software to preselect and rank cocrystal candidates (coformers). Second, high-throughput crystallization experiments (HTCS) were conducted on the selected coformers. The HTCS results were successfully reproduced by liquid-assisted grinding and reaction crystallization, ultimately leading to the synthesis of thirteen new posaconazole cocrystals (7 anhydrous, 5 hydrates, and 1 solvate). The posaconazole cocrystals were characterized by PXRD, 1H NMR, Fourier transform-Raman, thermogravimetry-Fourier transform infrared spectroscopy, and differential scanning calorimetry. In addition, the prediction performance of COSMOquick was compared to that of two alternative knowledge-based methods: molecular complementarity (MC) and hydrogen bond propensity (HBP). Although HBP does not perform better than random guessing for this case study, both MC and COSMOquick show good discriminatory ability, suggesting their use as a potential virtual tool to improve cocrystal screening.
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Affiliation(s)
- Matteo Guidetti
- Solid-State
Development Department, Solvias AG, Römerpark 2, CH-4303Kaiseraugst, Switzerland
| | - Rolf Hilfiker
- Solid-State
Development Department, Solvias AG, Römerpark 2, CH-4303Kaiseraugst, Switzerland
| | - Martin Kuentz
- Institute
of Pharma Technology, University of Applied
Sciences and Arts Northwestern Switzerland, CH-4132Muttenz, Switzerland
| | - Annette Bauer-Brandl
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Campusvej 55, 5230Odense, Denmark
| | - Fritz Blatter
- Solid-State
Development Department, Solvias AG, Römerpark 2, CH-4303Kaiseraugst, Switzerland
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Gafner S, Bastiaenen C, Ferrari S, Gold G, Terrier P, Hilfiker R, Allet L. The diagnostic accuracy of hip abductor strength in the fall risk of older persons. Ann Phys Rehabil Med 2018. [DOI: 10.1016/j.rehab.2018.05.787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Hilfiker R, Knutti IA, Raval-Roland B, Rivier G, Crombez G, Opsommer E. Erratum to: Validity and responsiveness of the French version of the Örebro Musculoskeletal Pain Screening Questionnaire in chronic low back pain. Eur Spine J 2017; 26:297. [PMID: 27885475 DOI: 10.1007/s00586-016-4866-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- R Hilfiker
- School of Health Sciences, University of Applied Sciences and Arts Western Switzerland (HES-SO) Valais-Wallis, Chemin de l'Agasse 5, 1950, Sion, Switzerland
| | - I A Knutti
- University of Applied Sciences and Arts Western Switzerland (HES-SO), School of Health Sciences (HESAV), Av. de Beaumont 21, 1011, Lausanne, Switzerland
| | - B Raval-Roland
- University of Applied Sciences and Arts Western Switzerland (HES-SO), School of Health Sciences (HESAV), Av. de Beaumont 21, 1011, Lausanne, Switzerland
| | - G Rivier
- Clinique Romande de Réadaptation, Av. du Grand-Champsec 90, 1950, Sion, Switzerland
| | - G Crombez
- Ghent University, Henri Dunantlaan 2, 9000, Ghent, Belgium
| | - Emmanuelle Opsommer
- University of Applied Sciences and Arts Western Switzerland (HES-SO), School of Health Sciences (HESAV), Av. de Beaumont 21, 1011, Lausanne, Switzerland.
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Janssen S, Trippolini M, Hilfiker R, Oesch P. Entwicklung einer Kurzversion des Spinal Function Sort (M-SFS): Ein Mixed-Method-Ansatz ,. physioscience 2016. [DOI: 10.1055/s-0035-1567112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- S. Janssen
- Arbeitsorientierte Rehabilitation, Rehaklinik Bellikon, Suva Care, Bellikon, Schweiz
| | - M. Trippolini
- Arbeitsorientierte Rehabilitation, Rehaklinik Bellikon, Suva Care, Bellikon, Schweiz
| | - R. Hilfiker
- HES-SO Valais-Wallis, Fachhochschule für Gesundheit Wallis, Sion, Schweiz
| | - P. Oesch
- Forschungsabteilung, Kliniken Valens, Valens, Schweiz
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Benz T, Angst F, Oesch P, Hilfiker R, Lehmann S, Mueller Mebes C, Kramer E, Verra ML. Comparison of patients in three different rehabilitation settings after knee or hip arthroplasty: a natural observational, prospective study. BMC Musculoskelet Disord 2015; 16:317. [PMID: 26497597 PMCID: PMC4619418 DOI: 10.1186/s12891-015-0780-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/16/2015] [Indexed: 11/29/2022] Open
Abstract
Background Patients after primary hip or knee replacement surgery can benefit from postoperative treatment in terms of improvement of independence in ambulation, transfers, range of motion and muscle strength. After discharge from hospital, patients are referred to different treatment destination and modalities: intensive inpatient rehabilitation (IR), cure (medically prescribed stay at a convalescence center), or ambulatory treatment (AT) at home. The purpose of this study was to 1) measure functional health (primary outcome) and function relevant factors in patients with hip or knee arthroplasty and to compare them in relation to three postoperative management strategies: AT, Cure and IR and 2) compare the post-operative changes in patient’s health status (between preoperative and the 6 month follow-up) for three rehabilitation settings. Methods Natural observational, prospective two-center study with follow-up. Sociodemographic data and functional mobility tests, Timed Up and Go (TUG) and Iowa Level of Assistance Scale (ILOAS) of 201 patients were analysed before arthroplasty and at the end of acute hospital stay (mean duration of stay: 9.7 days +/− 3.9). Changes in health state were measured with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) before and 6 months after arthroplasty. Results Compared to patients referred for IR and Cure, patients referred for AT were significantly younger and less comorbid. Patients admitted to IR had the highest functional disability before arthroplasty. Before rehabilitation, mean TUG was 40.0 s in the IR group, 33.9 s in the Cure group, and 27.5 s in the AT group, and corresponding mean ILOAS was 16.0, 13.0 and 12.2 (50.0 = worst). At the 6 months follow-up, the corresponding effect sizes of the WOMAC global score were 1.32, 1.87, and 1.51 (>0 means improvement). Conclusions Age, comorbidity and functional disability are associated with referral for intensive inpatient rehabilitation after hip or knee arthroplasty and partly affect health changes after rehabilitation.
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Affiliation(s)
- T Benz
- Research Department, RehaClinic, Bad Zurzach, Switzerland.
| | - F Angst
- Research Department, RehaClinic, Bad Zurzach, Switzerland.
| | - P Oesch
- Kliniken Valens, Rehabilitationszentrum Valens, Valens, Switzerland.
| | - R Hilfiker
- School of Health Sciences, HES-SO Valais-Wallis, Leukerbad, Switzerland.
| | - S Lehmann
- Research Department, RehaClinic, Bad Zurzach, Switzerland.
| | - C Mueller Mebes
- Department of Physiotherapy, Bern University Hospital, Bern, Switzerland.
| | - E Kramer
- Klinik Adelheid, Unterägeri, Switzerland.
| | - M L Verra
- Department of Physiotherapy, Bern University Hospital, Bern, Switzerland.
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Konzelmann M, Burrus C, Hilfiker R, Rivier G, Deriaz O, Luthi F. Cross-cultural adaptation, reliability, internal consistency and validation of the Hand Function Sort (HFS©) for French speaking patients with upper limb complaints. J Occup Rehabil 2015; 25:18-24. [PMID: 24839002 DOI: 10.1007/s10926-014-9514-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
INTRODUCTION Functional evaluation of upper limb is not only based on clinical findings but requires self-administered questionnaires to address patients' perspective. The Hand Function Sort (HFS©) was only validated in English. The aim of this study was the French cross cultural adaptation and validation of the HFS© (HFS-F). METHODS 150 patients with various upper limbs impairments were recruited in a rehabilitation center. Translation and cross-cultural adaptation were made according to international guidelines. Construct validity was estimated through correlations with Disabilities Arm Shoulder and Hand (DASH) questionnaire, SF-36 mental component summary (MCS),SF-36 physical component summary (PCS) and pain intensity. Internal consistency was assessed by Cronbach's α and test-retest reliability by intraclass correlation. RESULTS Cronbach's α was 0.98, test-retest reliability was excellent at 0.921 (95 % CI 0.871-0.971) same as original HFS©. Correlations with DASH were-0.779 (95 % CI -0.847 to -0.685); with SF 36 PCS 0.452 (95 % CI 0.276-0.599); with pain -0.247 (95 % CI -0.429 to -0.041); with SF 36 MCS 0.242 (95 % CI 0.042-0.422). There were no floor or ceiling effects. CONCLUSIONS The HFS-F has the same good psychometric properties as the original HFS© (internal consistency, test retest reliability, convergent validity with DASH, divergent validity with SF-36 MCS, and no floor or ceiling effects). The convergent validity with SF-36 PCS was poor; we found no correlation with pain. The HFS-F could be used with confidence in a population of working patients. Other studies are necessary to study its psychometric properties in other populations.
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Affiliation(s)
- M Konzelmann
- Service de réadaptation de l'appareil locomoteur, Clinique romande de réadaptation suvacare, Avenue du grand champsec, 90, 1950, Sion, Switzerland,
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Blaser-Sziede R, Hilfiker R, Heynen S, Meichtry A. Triggerpunkttherapie und Bewegungskontrolle bei Rückenschmerzen. Manuelle Medizin 2013. [DOI: 10.1007/s00337-013-1059-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Burrus C, Hilfiker R, Konzelmann M. Cross-cultural adaptation, and validation of the Hand Function Sort (HFS) questionnaire in a French-speaking population of upper limb injury. Ann Phys Rehabil Med 2012. [DOI: 10.1016/j.rehab.2012.07.160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Luthi F, Deriaz O, Hilfiker R. Validation of a predictive model for return to work after orthopaedic trauma. Ann Phys Rehabil Med 2012. [DOI: 10.1016/j.rehab.2012.07.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Luthi F, Deriaz O, Hilfiker R. Validation d’un modèle prédictif de retour au travail après un traumatisme orthopédique. Ann Phys Rehabil Med 2012. [DOI: 10.1016/j.rehab.2012.07.154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Burrus C, Hilfiker R, Konzelmann M. Adaptation transculturelle et validation du questionnaire Hand Function Sort (HFS) dans une population francophone d’accidentés du membre supérieur. Ann Phys Rehabil Med 2012. [DOI: 10.1016/j.rehab.2012.07.153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
A re-investigation of the crystalline state of methylene blue has led to the identification of five different hydrates with clearly distinct structures. These include the already known pentahydrate, a hydrate with 2.2-2.3 equivalents of water, two dihydrates, and a monohydrate. Contrary to older reports, no trihydrate was found. The preparation and characterization of the hydrates as well as the transformations between them are reported. The applied analytical methods include X-ray powder diffraction (XRPD), infrared spectroscopy (ATR-IR), thermogravimetry (TGA), differential scanning calorimetry (DSC), dynamic water vapor sorption (DVS) and solution calorimetry (SolCal). A phase diagram of temperature vs. composition has been established, and the stability domains of the different hydrates as a function of water activity and temperature have been determined based on data from DSC, SolCal and suspension equilibration experiments. Four out of the five hydrates are thermodynamically stable within a certain range of temperature and humidity.
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Affiliation(s)
- Timo Rager
- Solvias AG, Department for Solid-State Development, Römerpark 2, 4303 KAISERAUGST, Switzerland.
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Luginbuehl H, Lehmann C, Gerber R, Kuhn A, Hilfiker R, Baeyens JP, Radlinger L. Continuous versus intermittent stochastic resonance whole body vibration and its effect on pelvic floor muscle activity. Neurourol Urodyn 2012; 31:683-7. [PMID: 22395850 DOI: 10.1002/nau.21251] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 11/15/2011] [Indexed: 12/11/2022]
Abstract
AIMS To determine the optimal stochastic whole body vibration (SR-WBV) load modality regarding pelvic floor muscle (PFM) activity in order to complete the SR-WBV training methodology for future PFM training with SR-WBV. METHODS The continuous and the intermittent SR-WBV modalities were tested by means of electromyography in two independent groups (27 women 8 weeks to 1-year postpartum and 23 women nulliparae or >1-year postpartum) with self-reported stress urinary incontinence. The change in the PFM activity within a single set and over three sets were calculated for both SR-WBV modalities together (time effect) and for both SR-WBV modalities separately (modality-time interaction). RESULTS There was no statistically significant or clinically relevant change in PFM activity over time or PFM fatigue in either SR-WBV modality within one or three sets and no difference between the modalities or the groups. CONCLUSIONS The lack of change in PFM activity could be due to a no more than moderate to submaximal PFM activity during SR-WBV, the maintenance of reflexive PFM activity despite PFM fatigue or a compensation of slow red PFM fiber fatigue by an increase of innervation frequency and motor unit recruitment of the fast white fibers. As there is no SR-WBV modality dependent difference regarding PFM activity, the continuous modality is recommended in clinical practice as it is easier to apply and less time consuming.
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Affiliation(s)
- H Luginbuehl
- Bern University of Applied Sciences, Health, Bern, Switzerland.
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Abstract
Typical selection criteria for co-crystal formers include toxicological considerations, physico-chemical properties such as water solubility, and the functional groups that are available for interaction with the substance to be co-crystallized (e.g., a drug substance). Some degree of predictability for the formation of a crystalline multi-component compound is often claimed for certain combinations of functional groups. The expression crystal engineering has been coined for this strategy and combined with the concept of synthons from organic chemistry. Computer modeling may further improve the predictive potential based on interaction energies and steric aspects.
Thermodynamic considerations offer a complementary approach for targeted co-crystal search and development. They can provide selection criteria for suitable co-crystal formers and can also help to predict the most promising preparation conditions. This includes the potential to reduce experimental effort in co-crystal search and crystallization optimization significantly. Phase diagrams are the method of choice for visualizing the thermodynamic relationships and simplifying their application. Phase diagrams are thus a powerful and intuitive tool for planning co-crystal screenings and crystallization optimizations.
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Affiliation(s)
- Timo Rager
- Solvias AG Department for Solid-State Development, Römerpark 2, 4303 Kaiseraugst Switzerland
| | - Rolf Hilfiker
- Solvias AG Department for Solid-State Development, Römerpark 2, 4303 Kaiseraugst Switzerland
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Hilfiker R, Deriaz O, Luthi F. Facteurs prédictifs du recours à la kinésithérapie et à l’ergothérapie 2ans après réadaptation pour un traumatisme orthopédique. Ann Phys Rehabil Med 2011. [DOI: 10.1016/j.rehab.2011.07.471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Deriaz O, Luthi F, Hilfiker R. INTERMED predicts non-return to work in an occupational rehabilitation setting for individuals with orthopaedic trauma–part 2. Ann Phys Rehabil Med 2011. [DOI: 10.1016/j.rehab.2011.07.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Chryssochou E, Hilfiker R, Deriaz O, Luthi F, Konzelmann M. Construct validity of the French version of the PRWE (Patient Rated Wrist Evaluation) with the French version of the DASH (Disabilities Arm Shoulder and Hand) is good to very good in a population of patients with wrist injuries in an inpatient rehabilitation unit. Ann Phys Rehabil Med 2011. [DOI: 10.1016/j.rehab.2011.07.343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hilfiker R, Deriaz O, Luthi F. Predictors of physiotherapy and occupational therapy use two years after a vocational rehabilitation for orthopaedic trauma. Ann Phys Rehabil Med 2011. [DOI: 10.1016/j.rehab.2011.07.473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Luthi F, Hilfiker R, Deriaz O. INTERMED predicts non-return to work in an occupational rehabilitation setting for individuals with orthopaedic trauma–Part I. Ann Phys Rehabil Med 2011. [DOI: 10.1016/j.rehab.2011.07.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Taeymans J, Schmid S, Hilfiker R. Systematische Literaturstudien und Metaanalysen im physiotherapeutischen Kontext verstehen. physioscience 2011. [DOI: 10.1055/s-0031-1281855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
| | - S. Schmid
- Berner Fachhochschule, Gesundheit, CH-Bern
| | - R. Hilfiker
- Fachhochschule Westschweiz Wallis, Bereich Gesundheit & Soziale Arbeit – Physiotherapie, CH-Leukerbad
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Linden EVD, Bedeaux D, Hilfiker R, Eicke HF. Determination of the Bending Modulus in Microemulsions by Using the Dynamic Kerr Effect. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19910950806] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Hilfiker R, Eicke HF, Sager W, Steeb C, Hofmeier U, Gehrke R. Form and Structure Factors of Water/AOT/Oil Microemulsions from Synchrotron SAXS. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19900940611] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Abstract
The topology of ternary phase diagrams of systems that are forming salts, cocrystals, solvates, or hydrates is discussed based on a simple mathematical model. The considerations include the thermodynamic stability of the multi-component crystal relative to the individual components, the character of the interactions in solution, the effect of relative solubility of the components, the consequences of using liquid components, the formation of multi-component crystals with different stoichiometry, and the competition between cocrystals or salts and solvates. Based on the characteristics of the phase diagrams, recommendations are provided as to an efficient design of salt formation and cocrystallization experiments.
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Heitz CAM, Hilfiker R, Bachmann LM, Joronen H, Lorenz T, Uebelhart D, Klipstein A, Brunner F. Comparison of risk factors predicting return to work between patients with subacute and chronic non-specific low back pain: systematic review. Eur Spine J 2009; 18:1829-35. [PMID: 19565277 DOI: 10.1007/s00586-009-1083-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 06/14/2009] [Indexed: 10/20/2022]
Abstract
The objective of the study was to provide an inventory of predictive instruments and their constituting parameters associated with return to work in patients with subacute (2-10 weeks pain duration) and chronic (10-24 weeks pain duration) non-specific low back pain (NSLBP). Data sources included systematic review in Medline, Embase, Cinahl, Central, PEDro, Psyndex, PsychInfo/PsycLit, and Sociofile up to September 2008, in reference lists of systematic reviews on risk factors, and of included studies. For the systematic review, two reviewers independently assessed study eligibility and quality, and extracted data. Disagreements were resolved by consensus. Risk factors were inventorised and grouped into a somatic and psychosocial domain. 23 studies reporting on subacute and 16 studies reporting on chronic patients were included. The studies on subacute patients reported on a total of 56 biomedical factors out of which 35 (63%) were modifiable and 61 psychosocial factors out of which 51 (84%) were modifiable. The corresponding values in studies on chronic patients were 44 biomedical [27 (62%) modifiable] and 61 [40 (66%) modifiable] respectively. Our data suggest that the interdisciplinary approach in patients at risk to develop persistent NSLBP is justified in both, the subacute and chronic disease stages. Psychosocial interventions might be more effective in subacute stages since a higher proportion of modifiable risk factors were identified in that group.
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Affiliation(s)
- C A M Heitz
- Department of Rheumatology, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland
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Cieza A, Hilfiker R, Boonen A, van der Heijde D, Braun J, Stucki G. Towards an ICF-based clinical measure of functioning in people with ankylosing spondylitis: a methodological exploration. Disabil Rehabil 2009; 31:528-37. [PMID: 18608418 DOI: 10.1080/09638280802173475] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE To explore whether it is possible to construct clinical measures of functioning for patients with ankylosing spondylitis (AS) by integrating information obtained across categories of the International Classification of Functioning, Disability and Health (ICF). METHODS Sixty-eight ICF categories that were identified as relevant by patients with AS and that covered body functions, structures, and activity and participation were analysed based on the Rasch model for ordered response options. The following properties were studied: unidimensionality, reliability, fit of the ICF categories to the Rasch model, the appropriateness of the order of the response options of the ICF qualifier, and the targeting between the ICF categories and the person's abilities. RESULTS After accounting for disordered thresholds and misfitting ICF categories, a clinical measure of functioning for AS was proposed that contained 64 ICF categories. On the basis of a transformation table, the raw scores obtained by adding the answers to the 64 ICF categories can be transformed to the Rasch logit scale and to a meaningful interval scale ranging from zero to 100. CONCLUSION For the first time, it has been shown that clinical measures of functioning, in principle, can be constructed based on the comprehensive ICF framework covering body functions and structures and activities and participation domains. The results of this investigation are preliminary and must be validated, but they are promising and can contribute to the acceptance and usefulness of the ICF in clinical practice.
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Affiliation(s)
- A Cieza
- ICF Research Branch of the WHO Collaborating Center for the Family of International Classifications at the German Institute of Medical Documentation and Information (DIMDI), IHRS, Ludwig-Maximilian University, Munich, Germany
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Gies P, Roy C, McLennan A, Pailthorpe M, Hilfiker R, Osterwalder U, Monard B, Moseley H, Sliney D, Wengraitis S, Wong J, Human S, Bilimis Z, Holmes G. Ultraviolet Protection Factors for Clothing: An Intercomparison of Measurement Systems¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0770058upffca2.0.co2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Gies P, Roy C, McLennan A, Pailthorpe M, Hilfiker R, Osterwalder U, Monard B, Moseley H, Sliney D, Wengraitis S, Wong J, Human S, Bilimis Z, Holmes G. Ultraviolet protection factors for clothing: an intercomparison of measurement systems. Photochem Photobiol 2003; 77:58-67. [PMID: 12856884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
In recent years the need to standardize measurement protocols for quantifying the degree of ultraviolet radiation (UVR) protection provided by clothing has led to the introduction of a number of standards around the world. To date, these standards have specified spectral measurements of UVR transmission by clothing and fabrics. Development of a standard test method has become an important part of the testing process, and this article presents results from an intercomparison involving 10 independent testing laboratories and 11 different UVR transmission measurement instruments. In addition to comparing the measured ultraviolet protection factors (UPF), this intercomparison also incorporates detailed scan results from all 10 laboratories and highlights differences in performance of the various instruments in different wavelength regions. Careful examination of these differences can indicate where changes to the systems could be made to allow improvements both in equipment performance and in agreement of the final results. The variability in the measurements of UPF in this study suggest that the protection categories in standards may need to be broadened.
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Affiliation(s)
- Peter Gies
- Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), Melbourne, Australia.
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Eicke HF, Gauthier M, Hilfiker R, Struis RPWJ, Xu G. Conformations of telechelic ionomers in water/oil microemulsions. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100191a078] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hilfiker R, Von Raumer M, Geoffroy A, Blatter F, Haesslin HW. Bioperformance Improvement: Small Particles and Optimal Polymorphs. Chimia (Aarau) 2001. [DOI: 10.2533/chimia.2001.699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The average molar mass of active substances in crop protection as well as in pharmaceuticals has grown almost tenfold in the last century. In general, large molar masses are a drawback when looking at bioavailability. There are several strategies to overcome the problem of low bioavailability.
Two of those strategies will be discussed in this paper: (i) Increasing the dissolution rate of the solids by increasing the specific surface and (ii) increasing the solubility by choosing an optimal polymorph or an amorphous substance. It will be shown what physicochemical measurements are
useful to predict which excipients will stabilize suspensions of particles as small as 500 nm. In relation to optimal polymorphs, the importance of the optimal choice will be highlighted and examples of reliable stabilization of the amorphous form will be given.
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Madörin M, van Hoogevest P, Hilfiker R, Leuenberger H. The use of fluorescence resonance energy transfer to study the disintegration kinetics of liposomes containing lysolecithin and oleic acid in rat plasma. Pharm Res 2000; 17:1118-23. [PMID: 11087045 DOI: 10.1023/a:1026413914687] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To validate Fluorescence Resonance Energy Transfer (RET) as method to monitor disintegration of fluorescently labeled liposomes varying in lysolecithin/oleic acid (equimolar) content, lysolecithin fatty acid composition and vesicle size in rat blood plasma and buffer. METHODS NBD-PE and Rho-PE were used for RET. The measurements were performed on a Perkin Elmer LS-50 spectrofluorimeter. Liposomes were prepared by the extrusion method. RESULTS Analysis of the RET data was optimised using a fitting procedure to correct for fluorescence interference by plasma. The disintegration patterns of liposomes could be described by a biexponential decay model. Disintegration rate increased at increasing lysolecithin/oleic acid content and decreasing size. In contrast, all liposomes showed no disintegration in buffer. CONCLUSIONS RET is a suitable method to monitor liposome disintegration in non-diluted plasma. Rate and extent of liposome disintegration increases at decreasing liposome size and increasing lysolecithin/oleic acid content.
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Affiliation(s)
- M Madörin
- Pharmaceutical and Analytical Development, Novartis AG, Basel, Switzerland.
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Abstract
Single-nucleotide polymorphisms (SNPs), common variations among the DNA of individuals, are being uncovered and assembled into large SNP databases that promise to enable the dissection of the genetic basis of disease and drug response (i.e., pharmacogenomics). Although great strides have been made in understanding the diversity of the human genome, such as the frequency, distribution, and type of genetic variation that exists, the feasibility of applying this information to uncover useful pharmacogenomic markers is uncertain. The health care industry is clamoring for access to SNP databases for use in research in the hope of revolutionizing the drug development process. As the reality of using SNPs to uncover drug response markers is rarely addressed, this review discusses practical issues, such as patient sample size, SNP density and genome coverage, and data interpretation, that will be important for determining the applicability of pharmacogenomic information to medical practice.
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Affiliation(s)
- J J McCarthy
- Millennium Predictive Medicine, Inc., Cambridge, MA 02139, USA.
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Madörin M, van Hoogevest P, Hilfiker R, Langwost B, Kresbach GM, Ehrat M, Leuenberger H. Analysis of drug/plasma protein interactions by means of asymmetrical flow field-flow fractionation. Pharm Res 1997; 14:1706-12. [PMID: 9453057 DOI: 10.1023/a:1012171511285] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE The applicability of Asymmetrical Flow Field-Flow Fractionation (Asymmetrical Flow FFF) as an alternative tool to examine the distribution of a lipophilic drug (N-Benzoyl-staurosporine) within human plasma protein fractions was investigated with respect to high separation speed and loss of material on surfaces due to adsorption. METHODS Field-Flow Fractionation is defined as a group of pseudochromatographic separation methods, where compounds are separated under the influence of an externally applied force based on differences in their physicochemical properties. This method was used to separate human plasma in its protein fractions. The drug distribution in the fractions was investigated by monitoring the fractionated eluate for drug content by fluorescence spectroscopy. RESULTS Human plasma was separated into human serum albumin (HSA), high density lipoprotein (HDL), alpha 2-macroglobulin and low density lipoprotein (LDL) fractions in less than ten minutes. Calibration of the system and identification of the individual fractions was performed using commercially available protein reference standards. The influence of membrane type and carrier solution composition on the absolute recovery of N-Benzoyl-staurosporine and fluorescein-isothiocyanate-albumin (FITC-albumin) was found to be quite significant. Both factors were optimized during the course of the investigations. N-Benzoyl-staurosporine was found to be enriched in the fraction containing HSA. CONCLUSIONS If experimental conditions are thoroughly selected and controlled to suppress drug and plasma protein adsorption at the separation membrane, Asymmetrical Flow FFF shows high recoveries and fast separation of human plasma proteins, and can be a reliable tool to characterize drug/plasma protein interactions. For analytical purposes it has the potential to rival established technologies like ultracentrifugation in terms of ease-of-use, precision, and separation time.
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Affiliation(s)
- M Madörin
- Novartis Pharma AG, Basel, Switzerland
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Isele U, van Hoogevest P, Hilfiker R, Capraro HG, Schieweck K, Leuenberger H. Large-scale production of liposomes containing monomeric zinc phthalocyanine by controlled dilution of organic solvents. J Pharm Sci 1994; 83:1608-16. [PMID: 7891283 DOI: 10.1002/jps.2600831117] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This work describes the development of an organic solvent dilution method suitable for the large scale manufacturing of small unilamellar liposomes containing the water-insoluble photosensitizer zinc phthalocyanine in the monomeric state. N-Methyl pyrrolidone (NMP)/tert-butyl alcohol was selected as water miscible organic phase in which the phospholipids 1-palmitoyl, 2-oleoylphosphatidylcholine (POPC), and 1,2-dioeloylphosphatidylserine (OOPS) and the dye were dissolved. This organic phase was mixed with an excess of a water phase using a dynamic mixing device, yielding reproducibly unilamellar liposomes with a mean size of 50-150 nm as measured with quasielastic light scattering. After concentration, the organic solvents were efficiently removed by cross-flow filtration. The liposomes were then sterile filtered and freeze-dried. A method to measure the aggregation state of the dye in the liposomes was developed. A stable lyophilized formulation containing monomeric liposomal ZnPc could be obtained by using a solution of ZnPc in NMP (2 mg/mL) and ZnPc/phospholipid (1:100 w/w ratio) and performing concentration and dialysis at 4 degrees C and lyophilization in presence of a mixture of lactose and phospholipid (5:1 w/w ratio).
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Affiliation(s)
- U Isele
- Research and Development Department Ciba-Geigy Ltd., Basle, Switzerland
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Hilfiker R, Wu DQ, Chu B. Synchrotron SAXS measurements on solutions of poly(styrene-isoprene) AB block copolymer in aniline. J Colloid Interface Sci 1990. [DOI: 10.1016/0021-9797(90)90028-m] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Eicke HF, Hilfiker R, Xu G. Blockcopolymers in microemulsions differential heats of solution and shift of the percolation temperature in W/O microemulsions. Helv Chim Acta 1990. [DOI: 10.1002/hlca.19900730125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kim V, Hilfiker R, Eicke HF. Excess adsorption of hydrocarbons on the oil/water interface in H2O/AOT/oil microemulsions in the presence of additives. J Colloid Interface Sci 1988. [DOI: 10.1016/0021-9797(88)90460-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hilfiker R, Eicke HF. Self-consistency of the percolation model as applied to a macrofluid-like water-in-oil microemulsion. ACTA ACUST UNITED AC 1987. [DOI: 10.1039/f19878301621] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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