20 results on '"Frijlink, P."'
Search Results
2. The Effect of Food on the Pharmacokinetics of Buspirone After Single Administration of a Sublingual Testosterone and Oral Buspirone Combination Tablet in Healthy Female Subjects
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Jeroen Gerritsen, MSc, Jos Bloemers, PhD, Kim van Rooij, PhD, Leo de Leede, PhD, Ronald van der Geest, PhD, Henderik W. Frijlink, PhD, Hans P.F. Koppeschaar, MD, PhD, Berend Olivier, PhD, and Adriaan Tuiten, PhD
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Sublingual Testosterone ,Buspirone ,Food Effect ,Pharmacokinetics ,Female Sexual Interest ,Arousal Disorder (FSIAD) ,Medicine - Abstract
Introduction: A new combination tablet containing sublingual testosterone and oral buspirone (T+B) was developed to benefit a subgroup of women suffering from female sexual interest/arousal disorder, caused by dysfunctionally overactive sexual inhibition. Aim: The aim of this study was to compare the effect of food intake on the pharmacokinetics of buspirone, administered as a dual-route, dual-release combination tablet containing 0.5 mg testosterone (T) and 10 mg buspirone (B). Methods: 19 healthy women took T+B under fed and fasted conditions during 2 overnight visits. The blood was sampled over a 24-hour period to determine the pharmacokinetics of buspirone and its active metabolite 1-(2-pyrimidinyl)piperazine (1-PP). Total testosterone levels were also assessed, at 5 time points and for quality control purposes only, as sublingual testosterone uptake is not expected to be influenced by prior food intake. Main Outcome Measure: PK profiles of buspirone and 1-PP. Results: For buspirone, the 90% confidence intervals (CIs) of the observed fed/fasted ratios for the plasma area under the curve (AUC)0-last, AUC0-inf, and Cmax after administration of T+B were not contained within the prespecified bounds of 80% and 125%, except for the lower bound of AUC0-inf. However, the 90% CIs of the observed fed/fasted ratios for the plasma AUC0-last, AUC0-inf, and Cmax of 1-PP were contained within the prespecified bounds, with the exception of the upper bound for Cmax. The mean AUCs and Cmax for 1-PP did not differ between fed and fasted conditions. Conclusions: Administration of T+B after high-caloric food intake increased the bioavailability of buspirone but did not result in differences in Tmax when compared with fasted conditions. Both in fed and fasted conditions, T+B was generally well tolerated and safe. Exposure of 1-PP in fed and fasted conditions was comparable in both conditions. These results demonstrate that T+B can safely and effectively be used in both fed and fasted states.Gerritsen J, Bloemers J, van Rooij K, et al. The Effect of Food on the Pharmacokinetics of Buspirone After Single Administration of a Sublingual Testosterone and Oral Buspirone Combination Tablet in Healthy Female Subjects. J Sex Med 2020;8:186–194.
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- 2020
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3. Tolerability and pharmacokinetic evaluation of inhaled dry powder hydroxychloroquine in healthy volunteers.
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Y A de Reus, P Hagedoorn, M G G Sturkenboom, F Grasmeijer, M S Bolhuis, I Sibum, H A M Kerstjens, H W Frijlink, and O W Akkerman
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Medicine ,Science - Abstract
RationaleInhaled antimicrobials enable high local concentrations where needed and, compared to orally administration, greatly reduce the potential for systemic side effects. In SARS-CoV-2 infections, hydroxychloroquine sulphate (HCQ) administered as dry powder via inhalation could be safer than oral HCQ allowing higher and therefore more effective pulmonary concentrations without dose limiting toxic effects.ObjectivesTo assess the local tolerability, safety and pharmacokinetic parameters of HCQ inhalations in single ascending doses of 5, 10 and 20 mg using the Cyclops dry powder inhaler.MethodsTwelve healthy volunteers were included in the study. Local tolerability and safety were assessed by pulmonary function tests, electrocardiogram and recording adverse events. To estimate systemic exposure, serum samples were collected before and 0.5, 2 and 3.5 h after inhalation.Results and discussionDry powder HCQ inhalations were well tolerated by the participants, except for transient bitter taste in all participants and minor coughing irritation. There was no significant change in QTc-interval or drop in FEV1 post inhalation. The serum HCQ concentration remained below 10 μg/L in all samples.ConclusionSingle doses of inhaled dry powder HCQ up to 20 mg are safe and well tolerated. Our data support that further studies with inhaled HCQ dry powder to evaluate pulmonary pharmacokinetics and efficacy are warranted.
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- 2022
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4. Assessing the Immunomodulatory Effect of Size on the Uptake and Immunogenicity of Influenza- and Hepatitis B Subunit Vaccines In Vitro
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Rick Heida, Philip A. Born, Gabriela Tapia-Calle, Henderik W. Frijlink, Anna Salvati, Anke L. W. Huckriede, and Wouter L. J. Hinrichs
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dendritic cells ,drug delivery systems ,flow cytometry ,hepatitis B virus ,human peripheral blood mononuclear cells ,influenza virus ,Medicine ,Pharmacy and materia medica ,RS1-441 - Abstract
Viral subunit vaccines are a safer and more tolerable alternative to whole inactivated virus vaccines. However, they often come with limited efficacy, necessitating the use of adjuvants. Using free and particle-bound viral antigens, we assessed whether size affects the uptake of those antigens by human monocyte-derived dendritic cells (Mo-DCs) and whether differences in uptake affect their capacity to stimulate cytokine production by T cells. To this end, influenza antigens and hepatitis B surface antigen (HBsAg) were covalently conjugated to polystyrene particles of 500 nm and 3 μm. Cellular uptake of the antigens, either unconjugated or conjugated, and their capacity to stimulate T cells within a population of human peripheral blood mononuclear cells (PBMCs) were measured by flow cytometry. Conjugation of both antigens to particles significantly increased their uptake by Mo-DCs. Moreover, both the 500 nm and 3 μm influenza conjugates induced significantly higher numbers of cytokine-producing CD4+ T cells and induced increased production of the pro-inflammatory cytokines IFNγ and TNFα. In contrast, conjugation of HBsAg to particles did not notably affect the T cell response. In conclusion, conjugation of antigen to 500 nm and 3 μm particles leads to increased antigen uptake by human Mo-DCs, although the capacity of such conjugates to induce T cell stimulation likely depends on the immunological status of the PBMC donor.
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- 2022
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5. Colistin dry powder inhalation with the Twincer™: An effective and more patient friendly alternative to nebulization.
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A M Akkerman-Nijland, F Grasmeijer, H A M Kerstjens, H W Frijlink, H van der Vaart, J M Vonk, P Hagedoorn, B L Rottier, G H Koppelman, and O W Akkerman
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Medicine ,Science - Abstract
BackgroundNebulization of antimicrobial drugs such as tobramycin and colistin is a cornerstone in the treatment of patients with cystic fibrosis (CF) infected with Pseudomonas aeruginosa. However, nebulization has a high treatment burden. The Twincer™ is a dry powder inhaler specifically developed for the inhalation of antibiotics such as colistin. The aim of this study was to compare patient outcomes and experience with colistin dry powder by the Twincer with nebulization of colistin or tobramycin in adult CF patients in a real-life setting.MethodsThis was a retrospective study from 01-01-2015 until 01-07-2018. Effectiveness was evaluated by comparing FEV1 decline and exacerbation rate during a mean of 4.1 years of nebulization therapy prior to the initiation of the Twincer against the same values during a mean of 1.7 years of treatment with the Twincer.ResultsTwenty-one patients were evaluated, of whom twelve could be included in the effectiveness analysis, with a total of twenty patient years. Of all patients 71.4% preferred therapy with the Twincer over nebulization. Twincer use resulted in high treatment adherence with an average adherence rate of 92.5%. There was no significant difference in annual decline in FEV1%pred prior to and after start changing from nebulization to the use of the Twincer powder inhaler (median decline -1.56 [-5.57-5.31] and 1.35 [-8.45-6.36]) respectively, p = 0.45 (linear mixed effect model)). No significant difference was found in the number of intravenous or combined total intravenous and oral antibiotic courses during Twincer therapy compared to when using nebulization (1.68 and 2.49 courses during Twincer therapy versus 1.51 and 2.94 courses during nebulization, p = 0.88 and p = 0.63).ConclusionColistin dry powder inhalation with the Twincer is a more patient friendly alternative to nebulization, and we did not observe significant differences in the clinical outcome, regarding lung function and exacerbation rates.
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- 2020
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6. Genotype scores predict drug efficacy in subtypes of female sexual interest/arousal disorder: A double-blind, randomized, placebo-controlled cross-over trial
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Adriaan Tuiten, Frits Michiels, Koen BE Böcker, Daniël Höhle, Jack van Honk, Robert PJ de Lange, Kim van Rooij, Rob Kessels, Jos Bloemers, Jeroen Gerritsen, Paddy Janssen, Leo de Leede, John-Jules Meyer, Walter Everaerd, Henderik W Frijlink, Hans PF Koppeschaar, Berend Olivier, and James G Pfaus
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Medicine - Abstract
Attempts to develop a drug treatment for female sexual interest/arousal disorder have so far been guided by the principle of ‘one size fits all’, and have failed to acknowledge the complexity of female sexuality. Guided by personalized medicine, we designed two on-demand drugs targeting two distinct hypothesized causal mechanisms for this sexual disorder. The objective of this study was to design and test a novel procedure, based on genotyping, that predicts which of the two on-demand drugs will yield a positive treatment response. In a double-blind, randomized, placebo-controlled cross-over experiment, 139 women with female sexual interest/arousal disorder received three different on-demand drug-combination treatments during three 2-week periods: testosterone 0.5 mg + sildenafil 50 mg, testosterone 0.5 mg + buspirone 10 mg, and matching placebo. The primary endpoint was change in satisfactory sexual events. Subjects’ genetic profile was assessed using a microarray chip that measures 300,000 single-nucleotide polymorphisms. A preselection of single-nucleotide polymorphisms associated with genes that are shown to be involved in sexual behaviour were combined into a Phenotype Prediction Score. The Phenotype Prediction Score demarcation formula was developed and subsequently validated on separate data sets. Prediction of drug-responders with the Phenotype Prediction Score demarcation formula gave large effect sizes (d = 0.66 through 1.06) in the true drug-responders, and medium effect sizes (d = 0.51 and d = 0.47) in all patients (including identified double, and non-responders). Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the Phenotype Prediction Score demarcation formula were all between 0.78 and 0.79, and thus sufficient. The resulting Phenotype Prediction Score was validated and shown to effectively and reliably predict which women would benefit from which on-demand drug, and could therefore also be useful in clinical practice, as a companion diagnostic establishing the way to a true personalized medicine approach.
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- 2018
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7. Ovalbumin-containing core-shell implants suitable to obtain a delayed IgG1 antibody response in support of a biphasic pulsatile release profile in mice.
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Katie Amssoms, Philip A Born, Max Beugeling, Ben De Clerck, Ellen Van Gulck, Wouter L J Hinrichs, Henderik W Frijlink, Niels Grasmeijer, Guenter Kraus, Roger Sutmuller, Kenny Simmen, and Lieven Baert
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Medicine ,Science - Abstract
A single-injection vaccine formulation that provides for both a prime and a boost immunization would have various advantages over a multiple-injection regime. For such a vaccine formulation, it is essential that the booster dose is released after a certain, preferably adjustable, lag time. In this study we investigated whether a core-shell based implant, containing ovalbumin as core material and poly(DL-lactic-co-glycolic acid) of various monomer ratios as shell material can be used to obtain such a booster release. An in vitro release study showed that the lag time after which the ovalbumin was released from the core-shell implant increased with increasing lactic to glycolic acid ratio of the polymer and ranged from 3-6 weeks. Fluorescence spectroscopy showed minimal differences between native ovalbumin and ovalbumin from core-shell implants that were incubated until just before the observed in vitro release. In addition, mice immunized with a subcutaneous inserted core-shell implant containing ovalbumin showed an ovalbumin-specific IgG1 antibody response after a lag time of 4 or 6-8 weeks. Moreover, delayed release of ovalbumin caused higher IgG1 antibody titers than conventional subcutaneous vaccination with ovalbumin dissolved in PBS. Collectively, these findings could contribute to the further development of a single-injection vaccine, making multiple injections of the vaccine superfluous.
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- 2018
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8. Prerequisites for a dry powder inhaler for children with cystic fibrosis.
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Anne J Lexmond, Paul Hagedoorn, Henderik W Frijlink, Bart L Rottier, and Anne H de Boer
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Medicine ,Science - Abstract
Correct inhalation technique is essential for effective use of dry powder inhalers (DPIs), as their effectiveness largely depends on the patient's inhalation manoeuvre. Children are an especially challenging target population for DPI development due to the large variability in understanding and inspiratory capacities. We previously performed a study in which we determined the prerequisites for a paediatric DPI in a mostly healthy paediatric population, for which we used an empty test inhaler with variable internal airflow resistance and mouthpiece. In the current study we investigated what specifications are required for a DPI for children with cystic fibrosis (CF), for which we expanded on our previous findings. We recorded flow profiles of 35 children with CF (aged 4.7-14.7 years) at three airflow resistances (0.031-0.045 kPa0.5.min.L-1) from which various inspiratory parameters were computed. Obstructions in the mouth during inhalation were recorded with a sinuscope. All children were able to perform a correct inhalation manoeuvre, although video analysis showed that children did not place the inhaler correctly in the mouth in 17% of the cases. No effect was found of medium to high airflow resistance on total inhaled volume, which implies that the whole resistance range tested is suitable for children with CF aged 4-14 years. No effect could be established of either mouthpiece design or airflow resistance on the occurrence of obstructions in the mouth cavity. This study confirms our previous conclusion that the development of DPIs specifically for children is highly desired. Such a paediatric DPI should function well at 0.5 L inhaled volume and a peak inspiratory flow rate of 20 to 30 L/min, depending on the internal airflow resistance. This resistance can be increased up to 0.045 kPa0.5.min.L-1 (medium-high) to reduce oropharyngeal deposition. A higher resistance may be less favourable due to its compromising effect on PIF and thereby on the energy available for powder dispersion.
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- 2017
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9. Tolerability and Pharmacokinetic Evaluation of Inhaled Dry Powder Tobramycin Free Base in Non-Cystic Fibrosis Bronchiectasis Patients.
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Marcel Hoppentocht, Onno W Akkerman, Paul Hagedoorn, Jan-Willem C Alffenaar, Tjip S van der Werf, Huib A M Kerstjens, Henderik W Frijlink, and Anne H de Boer
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Medicine ,Science - Abstract
RATIONALE:Bronchiectasis is a condition characterised by dilated and thick-walled bronchi. The presence of Pseudomonas aeruginosa in bronchiectasis is associated with a higher hospitalisation frequency and a reduced quality of life, requiring frequent and adequate treatment with antibiotics. OBJECTIVES:To assess local tolerability and the pharmacokinetic parameters of inhaled excipient free dry powder tobramycin as free base administered with the Cyclops dry powder inhaler to participants with non-cystic fibrosis bronchiectasis. The free base and absence of excipients reduces the inhaled powder dose. METHODS:Eight participants in the study were trained in handling the device and inhaling correctly. During drug administration the inspiratory flow curve was recorded. Local tolerability was assessed by spirometry and recording adverse events. Serum samples were collected before, and 15, 30, 45, 60, 75, 90, 105, 120 min; 4, 8 and 12 h after inhalation. RESULTS AND DISCUSSION:Dry powder tobramycin base was well tolerated and mild tobramycin-related cough was reported only once. A good drug dose-serum concentration correlation was obtained. Relatively small inhaled volumes were computed from the recorded flow curves, resulting in presumably substantial deposition in the central airways-i.e., at the site of infection. CONCLUSIONS:In this first study of inhaled dry powder tobramycin free base in non-cystic fibrosis bronchiectasis patients, the free base of tobramycin and the administration with the Cyclops dry powder device were well tolerated. Our data support further clinical studies to evaluate safety and efficacy of this compound in this population.
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- 2016
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10. The Production of a Stable Infliximab Powder: The Evaluation of Spray and Freeze-Drying for Production.
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Gaurav Kanojia, Rimko Ten Have, Arjen Bakker, Koen Wagner, Henderik W Frijlink, Gideon F A Kersten, and Jean-Pierre Amorij
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Medicine ,Science - Abstract
In prospect of developing an oral dosage form of Infliximab, for treatment of Crohn's disease and rheumatoid arthritis, freeze-drying (vial vs Lyoguard trays) and spray-drying were investigated as production method for stable powders. Dextran and inulin were used in combination with sucrose as stabilizing excipients. The drying processes did not affect Infliximab in these formulations, i.e. both the physical integrity and biological activity (TNF binding) were retained. Accelerated stability studies (1 month at 60°C) showed that the TNF binding ability of Infliximab was conserved in the freeze-dried formulations, whereas the liquid counterpart lost all TNF binding. After thermal treatment, the dried formulations showed some chemical modification of the IgG in the dextran-sucrose formulation, probably due to Maillard reaction products. This study indicates that, with the appropriate formulation, both spray-drying and freeze-drying may be useful for (bulk) powder production of Infliximab.
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- 2016
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11. Gastrointestinal pH and Transit Time Profiling in Healthy Volunteers Using the IntelliCap System Confirms Ileo-Colonic Release of ColoPulse Tablets.
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Jacoba M Maurer, Reinout C A Schellekens, Hèlen M van Rieke, Christoph Wanke, Ventzeslav Iordanov, Frans Stellaard, Klaus D Wutzke, Gerard Dijkstra, Margot van der Zee, Herman J Woerdenbag, Henderik W Frijlink, and Jos G W Kosterink
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Medicine ,Science - Abstract
ColoPulse tablets are an innovative development in the field of oral dosage forms characterized by a distal ileum and colon-specific release. Previous studies in humans showed release in the ileo-colonic region, but the relationship between gastrointestinal pH and release was not experimentally proven in vivo. This information will complete the in vivo release-profile of ColoPulse tablets.Release from ColoPulse tablets was studied in 16 healthy volunteers using the dual label isotope strategy. To determine gastrointestinal pH profiles and transit times the IntelliCap system was used. A ColoPulse tablet containing 13C-urea and an uncoated, immediate release tablet containing 15N2-urea were taken simultaneously followed by a standardized breakfast after three hours. Five minutes after intake of the tablets the IntelliCap capsule was swallowed and pH was measured until excretion in the feces. Breath and urine samples were collected for isotope analysis.Full analysis could be performed in 12 subjects. Median bioavailability of 13C -urea was 82% (95% CI 74-94%, range 61-114%). The median lag time (5% release of 13C) was 5:42 h (95% CI 5:18-6:18 h, range 2:36-6:36 h,) There was no statistically significant difference between lag time based on isotope signal and colon arrival time (CAT) based on pH (median 5:42 vs 5:31 h p = 0.903). In all subjects an intestinal pH value of 7.0 was reached before release of 13C from the ColoPulse tablet occurred.From the combined data from the IntelliCap system and the 13C -isotope signal it can be concluded that release from a ColoPulse tablet in vivo is not related to transit times but occurs in the ileo-colonic region after pH 7.0 is reached. This supports our earlier findings and confirms that the ColoPulse system is a promising delivery system for targeting the distal ileum and colon.ISRCTN Registry 18301880.
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- 2015
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12. Can Patients with Parkinson's Disease Use Dry Powder Inhalers during Off Periods?
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M Luinstra, A W F Rutgers, H Dijkstra, F Grasmeijer, P Hagedoorn, J M J Vogelzang, H W Frijlink, and A H de Boer
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Medicine ,Science - Abstract
Because of its rapid onset of action, pulmonary administration of levodopa is an interesting alternative to oral administration for the rescue treatment of Parkinson's disease patients in an off period. We studied the ability of Parkinson's disease patients to operate a dry powder inhaler (DPI) correctly during an off period. We used an instrumented test inhaler with three different resistances to air flow to record flow curves and computed various inhalation parameters. We observed that all (13) patients were able to generate pressure drops > 2 kPa over the highest resistance and 10 out of 13 patients achieved at least 4 kPa. Inhaled volumes (all resistances) varied from 1.2 L to 3.5 L. Total inhalation time and the time to peak inspiratory flow rate both decreased with decreasing inhaler resistance. Twelve out of thirteen patients could hold their breath for at least five seconds after inhalation and nine could extend this time to ten seconds. The data from this study indicate that patients with Parkinson's disease will indeed be able to use a dry powder inhaler during an off period and they provide an adequate starting point for the development of a levodopa powder inhaler to treat this particular patient group.
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- 2015
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13. Adjuvantation of Pulmonary-Administered Influenza Vaccine with GPI-0100 Primarily Stimulates Antibody Production and Memory B Cell Proliferation
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Harshad P. Patil, José Herrera Rodriguez, Jacqueline de Vries-Idema, Tjarko Meijerhof, Henderik W. Frijlink, Wouter L. J. Hinrichs, and Anke Huckriede
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influenza ,pulmonary immunization ,adjuvant ,immune mechanisms ,Medicine - Abstract
Adjuvants are key components in vaccines, they help in reducing the required antigen dose but also modulate the phenotype of the induced immune response. We previously showed that GPI-0100, a saponin-derived adjuvant, enhances antigen-specific mucosal and systemic antibody responses to influenza subunit and whole inactivated influenza virus (WIV) vaccine administered via the pulmonary route. However, the impact of the GPI-0100 dose on immune stimulation and the immune mechanisms stimulated by GPI-0100 along with antigen are poorly understood. Therefore, in this study we immunized C57BL/6 mice via the pulmonary route with vaccine consisting of WIV combined with increasing amounts of GPI-0100, formulated as a dry powder. Adjuvantation of WIV enhanced influenza-specific mucosal and systemic immune responses, with intermediate doses of 5 and 7.5 μg GPI-0100 being most effective. The predominant antibody subtype induced by GPI-0100-adjuvanted vaccine was IgG1. Compared to non-adjuvanted vaccine, GPI-0100-adjuvanted WIV vaccine gave rise to higher numbers of antigen-specific IgA- but not IgG-producing B cells in the lungs along with better mucosal and systemic memory B cell responses. The GPI-0100 dose was negatively correlated with the number of influenza-specific IFNγ- and IL17-producing T cells and positively correlated with the number of IL4-producing T cells observed after immunization and challenge. Overall, our results show that adjuvantation of pulmonary-delivered WIV with GPI-0100 mostly affects B cell responses and effectively induces B cell memory.
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- 2017
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14. New mechanisms to explain the effects of added lactose fines on the dispersion performance of adhesive mixtures for inhalation.
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Floris Grasmeijer, Anne J Lexmond, Maarten van den Noort, Paul Hagedoorn, Anthony J Hickey, Henderik W Frijlink, and Anne H de Boer
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Medicine ,Science - Abstract
Fine excipient particles or 'fines' have been shown to improve the dispersion performance of carrier-based formulations for dry powder inhalation. Mechanistic formulation studies have focussed mainly on explaining this positive effect. Previous studies have shown that higher drug contents may cause a decrease in dispersion performance, and there is no reason why this should not be true for fines with a similar shape, size and cohesiveness as drug particles. Therefore, the effects on drug detachment of 'fine lactose fines' (FLF, X50 = 1.95 µm) with a similar size and shape as micronised budesonide were studied and compared to those of 'coarse lactose fines' (CLF, X50 = 3.94 µm). Furthermore, interactions with the inhalation flow rate, the drug content and the mixing order were taken into account. The observed effects of FLF are comparable to drug content effects in that the detached drug fraction was decreased at low drug content and low flow rates but increased at higher flow rates. At high drug content the effects of added FLF were negligible. In contrast, CLF resulted in higher detached drug fractions at all flow rates and drug contents. The results from this study suggest that the effects of fines may be explained by two new mechanisms in addition to those previously proposed. Firstly, fines below a certain size may increase the effectiveness of press-on forces or cause the formation of strongly coherent fine particle networks on the carrier surface containing the drug particles. Secondly, when coarse enough, fines may prevent the formation of, or disrupt such fine particle networks, possibly through a lowering of their tensile strength. It is recommended that future mechanistic studies are based on the recognition that added fines may have any effect on dispersion performance, which is determined by the formulation and dispersion conditions.
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- 2014
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15. Stability of lysozyme in aqueous extremolyte solutions during heat shock and accelerated thermal conditions.
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Christina Avanti, Vinay Saluja, Erwin L P van Streun, Henderik W Frijlink, and Wouter L J Hinrichs
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Medicine ,Science - Abstract
The purpose of this study was to investigate the stability of lysozyme in aqueous solutions in the presence of various extremolytes (betaine, hydroxyectoine, trehalose, ectoine, and firoin) under different stress conditions. The stability of lysozyme was determined by Nile red Fluorescence Spectroscopy and a bioactivity assay. During heat shock (10 min at 70°C), betaine, trehalose, ectoin and firoin protected lysozyme against inactivation while hydroxyectoine, did not have a significant effect. During accelerated thermal conditions (4 weeks at 55°C), firoin also acted as a stabilizer. In contrast, betaine, hydroxyectoine, trehalose and ectoine destabilized lysozyme under this condition. These findings surprisingly indicate that some extremolytes can stabilize a protein under certain stress conditions but destabilize the same protein under other stress conditions. Therefore it is suggested that for the screening extremolytes to be used for protein stabilization, an appropriate storage conditions should also be taken into account.
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- 2014
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16. Effect of inhaler design variables on paediatric use of dry powder inhalers.
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Anne J Lexmond, Tonnis J Kruizinga, Paul Hagedoorn, Bart L Rottier, Henderik W Frijlink, and Anne H de Boer
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Medicine ,Science - Abstract
Age appropriateness is a major concern of pulmonary delivery devices, in particular of dry powder inhalers (DPIs), since their performance strongly depends on the inspiratory flow manoeuvre of the patient. Previous research on the use of DPIs by children focused mostly on specific DPIs or single inspiratory parameters. In this study, we investigated the requirements for a paediatric DPI more broadly using an instrumented test inhaler. Our primary aim was to assess the impact of airflow resistance on children's inspiratory flow profiles. Additionally, we investigated children's preferences for airflow resistance and mouthpiece design and how these relate to what may be most suitable for them. We tested 98 children (aged 4.7-12.6 years), of whom 91 were able to perform one or more correct inhalations through the test inhaler. We recorded flow profiles at five airflow resistances ranging from 0.025 to 0.055 kPa0.5.min.L-1 and computed various inspiratory flow parameters from these recordings. A sinuscope was used to observe any obstructions in the oral cavity during inhalation. 256 flow profiles were included for analysis. We found that both airflow resistance and the children's characteristics affect the inspiratory parameters. Our data suggest that a medium-high resistance is both suitable for and well appreciated by children aged 5-12 years. High incidences (up to 90%) of obstructions were found, which may restrict the use of DPIs by children. However, an oblong mouthpiece that was preferred the most appeared to positively affect the passageway through the oral cavity. To accommodate children from the age of 5 years onwards, a DPI should deliver a sufficiently high fine particle dose within an inhaled volume of 0.5 L and at a peak inspiratory flow rate of 25-40 L.min-1. We recommend taking these requirements into account for future paediatric inhaler development.
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- 2014
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17. A user-friendly model for spray drying to aid pharmaceutical product development.
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Niels Grasmeijer, Hans de Waard, Wouter L J Hinrichs, and Henderik W Frijlink
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Medicine ,Science - Abstract
The aim of this study was to develop a user-friendly model for spray drying that can aid in the development of a pharmaceutical product, by shifting from a trial-and-error towards a quality-by-design approach. To achieve this, a spray dryer model was developed in commercial and open source spreadsheet software. The output of the model was first fitted to the experimental output of a Büchi B-290 spray dryer and subsequently validated. The predicted outlet temperatures of the spray dryer model matched the experimental values very well over the entire range of spray dryer settings that were tested. Finally, the model was applied to produce glassy sugars by spray drying, an often used excipient in formulations of biopharmaceuticals. For the production of glassy sugars, the model was extended to predict the relative humidity at the outlet, which is not measured in the spray dryer by default. This extended model was then successfully used to predict whether specific settings were suitable for producing glassy trehalose and inulin by spray drying. In conclusion, a spray dryer model was developed that is able to predict the output parameters of the spray drying process. The model can aid the development of spray dried pharmaceutical products by shifting from a trial-and-error towards a quality-by-design approach.
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- 2013
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18. Correction: Mixing Time Effects on the Dispersion Performance of Adhesive Mixtures for Inhalation.
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Floris Grasmeijer, Paul Hagedoorn, Henderik W. Frijlink, and H. Anne de Boer
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Medicine ,Science - Published
- 2013
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19. Drug content effects on the dispersion performance of adhesive mixtures for inhalation.
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Floris Grasmeijer, Paul Hagedoorn, Henderik W Frijlink, and Anne H de Boer
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Medicine ,Science - Abstract
The drug content in adhesive mixtures for inhalation is known to influence their dispersion performance, but the direction and magnitude of this influence depends on other variables. In the past decades several mechanisms have been postulated to explain this finding and a number of possible interacting variables have been identified. Still, the role of drug content in the formulation of adhesive mixtures for inhalation, which includes its significance as an interacting variable to other parameters, is poorly understood. Therefore, the results from a series of drug detachment experiments are presented in which the effect of drug content and its dependence on flow rate, the mixing time and the type of drug is studied. Furthermore, it is investigated whether the effect depends on the range within which the drug content is changed. Quantitative and qualitative multiple order interactions are observed between these variables, which may be explained by a shifting balance between three different mechanisms. The results therefore demonstrate that accounting for (multiple order) interactions between variables has to be part of quality by design activities and the rational design of future experiments.
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- 2013
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20. Mixing time effects on the dispersion performance of adhesive mixtures for inhalation.
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Floris Grasmeijer, Paul Hagedoorn, Henderik W Frijlink, and H Anne de Boer
- Subjects
Medicine ,Science - Abstract
This paper deals with the effects of mixing time on the homogeneity and dispersion performance of adhesive mixtures for inhalation. Interactions between these effects and the carrier size fraction, the type of drug and the inhalation flow rate were studied. Furthermore, it was examined whether or not changes in the dispersion performance as a result of prolonged mixing can be explained with a balance of three processes that occur during mixing, knowing drug redistribution over the lactose carrier; (de-) agglomeration of the drug (and fine lactose) particles; and compression of the drug particles onto the carrier surface. For this purpose, mixtures containing salmeterol xinafoate or fluticasone propionate were mixed for different periods of time with a fine or coarse crystalline lactose carrier in a Turbula mixer. Drug detachment experiments were performed using a classifier based inhaler at different flow rates. Scanning electron microscopy and laser diffraction techniques were used to measure drug distribution and agglomeration, whereas changes in the apparent solubility were measured as a means to monitor the degree of mechanical stress imparted on the drug particles. No clear trend between mixing time and content uniformity was observed. Quantitative and qualitative interactions between the effect of mixing time on drug detachment and the type of drug, the carrier size fraction and the flow rate were measured, which could be explained with the three processes mentioned. Generally, prolonged mixing caused drug detachment to decrease, with the strongest decline occurring in the first 120 minutes of mixing. For the most cohesive drug (salmeterol) and the coarse carrier, agglomerate formation seemed to dominate the overall effect of mixing time at a low inhalation flow rate, causing drug detachment to increase with prolonged mixing. The optimal mixing time will thus depend on the formulation purpose and the choice for other, interacting variables.
- Published
- 2013
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