Robbert Jan Kok
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
Robbert Jan Kok has a total of 556 co-authors. Here are the top co-authors by number of shared publications:
- Grietje Molema
Department of Pathology and Medical Biology, Medical Biology section, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
23 shared publications Wim E. Hennink
Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
21 shared publicationsGert Storm
Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
18 shared publicationsMarie Lacombe
LinXis B.V., Amsterdam, The Netherlands
13 shared publications- Jai Prakash
Department of Medical Biosciences Radboud University Medical Centre Nijmegen the Netherlands
12 shared publications Klaas Poelstra
Department of Pharmacokinetics and Drug Delivery, Groningen University Institute for Drug Exploration, Groningen, The Netherlands
12 shared publications
Latest Publications
- Open Access
- 9 November 2026
- Published by Elsevier in European Journal of Pharmaceutical Sciences
Automated Extrusion-based Dispensing of Mucoadhesive Oral Films Containing Buprenorphine for Feline Delivery to the Gingiva
- 9 November 2026
- Published by Elsevier in European Journal of Pharmaceutical Sciences
Open AccessAutomated Extrusion-based Dispensing of Mucoadhesive Oral Films Containing Buprenorphine for Feline Delivery to the Gingiva
- Open Access
- 9 October 2026
- Published by Elsevier in Journal of Pharmaceutical Sciences
Particle engineering enables laser powder bed fusion of highly loaded metoprolol tablets at room temperature
- 9 October 2026
- Published by Elsevier in Journal of Pharmaceutical Sciences
Open AccessParticle engineering enables laser powder bed fusion of highly loaded metoprolol tablets at room temperature
- Open Access
- 14 February 2026
- Published by Elsevier in International Journal of Pharmaceutics
- Vol. 693, 126677
A highly absorbing substrate based on functionalized calcium carbonate for personalized dosing of clonidine by drop-on dispensing
- 14 February 2026
- Published by Elsevier in International Journal of Pharmaceutics
- Vol. 693, 126677
Open AccessA highly absorbing substrate based on functionalized calcium carbonate for personalized dosing of clonidine by drop-on dispensing
- Open Access
- 31 July 2025
- Published by MDPI AG in Pharmaceutics
- Vol. 17 (8) , 1005
Extemporaneous Compounding, Pharmacy Preparations and Related Product Care in the Netherlands
Background/Objectives: In many parts of the world, pharmacists hold the primary responsibility for providing safe and effective pharmacotherapy. A key aspect is the availability of appropriate medicines for each individual patient. When industrially manufactured medicines are unsuitable or unavailable, pharmacists can prepare tailor-made medicines. While this principle applies globally, practices vary between countries. In the Netherlands, the preparation of medicines in pharmacies is well-established and integrated into routine healthcare. This narrative review explores the role and significance of extemporaneous compounding, pharmacy preparations and related product care in the Netherlands. Methods: Pharmacists involved in pharmacy preparations across various professional sectors, including community and hospital pharmacies, central compounding facilities, academia, and the professional pharmacists’ organisation, provided detailed and expert insights based on the literature and policy documents while also sharing their critical perspectives. Results: We present arguments supporting the need for pharmacy preparations and examine their position and role in community and hospital pharmacies in the Netherlands. Additional topics are discussed, including the regulatory and legal framework, outsourcing, quality assurance, standardisation, education, and international context. Specific pharmacy preparation topics, often with a research component and a strong focus on product care, are highlighted, including paediatric dosage forms, swallowing difficulties and feeding tubes, hospital-at-home care, reconstitution of oncolytic drugs and biologicals, total parenteral nutrition (TPN), advanced therapy medicinal products (ATMPs), radiopharmaceuticals and optical tracers, clinical trial medication, robotisation in reconstitution, and patient-centric solid oral dosage forms. Conclusions: The widespread acceptance of pharmacy preparations in the Netherlands is the result of a unique combination of strict adherence to tailored regulations that ensure quality and safety, and patient-oriented flexibility in design, formulation, and production. This approach is further reinforced by the standardisation of a broad range of formulations and procedures across primary, secondary and tertiary care, as well as by continuous research-driven innovation to develop new medicines, formulations, and production methods.
- 31 July 2025
- Published by MDPI AG in Pharmaceutics
- Vol. 17 (8) , 1005
Open AccessExtemporaneous Compounding, Pharmacy Preparations and Related Product Care in the Netherlands
Background/Objectives: In many parts of the world, pharmacists hold the primary responsibility for providing safe and effective pharmacotherapy. A key aspect is the availability of appropriate medicines for each individual patient. When industrially manufactured medicines are unsuitable or unavailable, pharmacists can prepare tailor-made medicines. While this principle applies globally, practices vary between countries. In the Netherlands, the preparation of medicines in pharmacies is well-established and integrated into routine healthcare. This narrative review explores the role and significance of extemporaneous compounding, pharmacy preparations and related product care in the Netherlands. Methods: Pharmacists involved in pharmacy preparations across various professional sectors, including community and hospital pharmacies, central compounding facilities, academia, and the professional pharmacists’ organisation, provided detailed and expert insights based on the literature and policy documents while also sharing their critical perspectives. Results: We present arguments supporting the need for pharmacy preparations and examine their position and role in community and hospital pharmacies in the Netherlands. Additional topics are discussed, including the regulatory and legal framework, outsourcing, quality assurance, standardisation, education, and international context. Specific pharmacy preparation topics, often with a research component and a strong focus on product care, are highlighted, including paediatric dosage forms, swallowing difficulties and feeding tubes, hospital-at-home care, reconstitution of oncolytic drugs and biologicals, total parenteral nutrition (TPN), advanced therapy medicinal products (ATMPs), radiopharmaceuticals and optical tracers, clinical trial medication, robotisation in reconstitution, and patient-centric solid oral dosage forms. Conclusions: The widespread acceptance of pharmacy preparations in the Netherlands is the result of a unique combination of strict adherence to tailored regulations that ensure quality and safety, and patient-oriented flexibility in design, formulation, and production. This approach is further reinforced by the standardisation of a broad range of formulations and procedures across primary, secondary and tertiary care, as well as by continuous research-driven innovation to develop new medicines, formulations, and production methods.
- Open Access
- 15 October 2024
- Published by Rockefeller University Press in Journal of Experimental Medicine
- Vol. 221 (11)
Uniting education, research, healthcare, and society to advance women’s heart health
Complex health challenges require professionals to operate across disciplines and to better connect with society. Here, we showcase a community-engaged and challenge-based educational model in which undergraduate students conduct transdisciplinary research on authentic complex biomedical problems. This concept reinforces translational medicine, human capital, and exemplifies synergy between education, research, healthcare, and society.
- 15 October 2024
- Published by Rockefeller University Press in Journal of Experimental Medicine
- Vol. 221 (11)
Open AccessUniting education, research, healthcare, and society to advance women’s heart health
Complex health challenges require professionals to operate across disciplines and to better connect with society. Here, we showcase a community-engaged and challenge-based educational model in which undergraduate students conduct transdisciplinary research on authentic complex biomedical problems. This concept reinforces translational medicine, human capital, and exemplifies synergy between education, research, healthcare, and society.
- Open Access
- 16 August 2022
- Published by American Chemical Society (ACS) in Molecular Pharmaceutics
- Vol. 19 (9) , 3057-3074
Utility of Intravenous Curcumin Nanodelivery Systems for Improving In Vivo Pharmacokinetics and Anticancer Pharmacodynamics
Curcumin nanoformulations for intravenous injection have been developed to offset poor absorption, biotransformation, degradation, and excessive clearance associated with parenteral delivery. This review investigates (1) whether intravenous nanoformulations improve curcumin pharmacokinetics (PK) and (2) whether improved PK yields greater therapeutic efficacy. Standard PK parameters (measured maximum concentration [Cmax], area under the curve [AUC], distribution volume [Vd], and clearance [CL]) of intravenously administered free curcumin in mice and rats were sourced from literature and compared to curcumin formulated in nanoparticles, micelles, and liposomes. The studies that also featured analysis of pharmacodynamics (PD) in murine cancer models were used to determine whether improved PK of nanoencapsulated curcumin resulted in improved PD. The distribution and clearance of free and nanoformulated curcumin were very fast, typically accounting for >80% curcumin elimination from plasma within 60 min. Case-matched analysis demonstrated that curcumin nanoencapsulation generally improved curcumin PK in terms of measured Cmax (n = 27) and AUC (n = 33), and to a lesser extent Vd and CL. However, when the data were unpaired and clustered for comparative analysis, only 5 out of the 12 analyzed nanoformulations maintained a higher relative curcumin concentration in plasma over time compared to free curcumin. Quantitative analysis of the mean plasma concentration of free curcumin versus nanoformulated curcumin did not reveal an overall marked improvement in curcumin PK. No correlation was found between PK and PD, suggesting that augmentation of the systemic presence of curcumin does not necessarily lead to greater therapeutic efficacy.
- 16 August 2022
- Published by American Chemical Society (ACS) in Molecular Pharmaceutics
- Vol. 19 (9) , 3057-3074
Open AccessUtility of Intravenous Curcumin Nanodelivery Systems for Improving In Vivo Pharmacokinetics and Anticancer Pharmacodynamics
Curcumin nanoformulations for intravenous injection have been developed to offset poor absorption, biotransformation, degradation, and excessive clearance associated with parenteral delivery. This review investigates (1) whether intravenous nanoformulations improve curcumin pharmacokinetics (PK) and (2) whether improved PK yields greater therapeutic efficacy. Standard PK parameters (measured maximum concentration [Cmax], area under the curve [AUC], distribution volume [Vd], and clearance [CL]) of intravenously administered free curcumin in mice and rats were sourced from literature and compared to curcumin formulated in nanoparticles, micelles, and liposomes. The studies that also featured analysis of pharmacodynamics (PD) in murine cancer models were used to determine whether improved PK of nanoencapsulated curcumin resulted in improved PD. The distribution and clearance of free and nanoformulated curcumin were very fast, typically accounting for >80% curcumin elimination from plasma within 60 min. Case-matched analysis demonstrated that curcumin nanoencapsulation generally improved curcumin PK in terms of measured Cmax (n = 27) and AUC (n = 33), and to a lesser extent Vd and CL. However, when the data were unpaired and clustered for comparative analysis, only 5 out of the 12 analyzed nanoformulations maintained a higher relative curcumin concentration in plasma over time compared to free curcumin. Quantitative analysis of the mean plasma concentration of free curcumin versus nanoformulated curcumin did not reveal an overall marked improvement in curcumin PK. No correlation was found between PK and PD, suggesting that augmentation of the systemic presence of curcumin does not necessarily lead to greater therapeutic efficacy.
- Open Access
- 4 December 2021
- Published by MDPI AG in Pharmaceutics
- Vol. 13 (12) , 2077
Assessing the Effects of VEGF Releasing Microspheres on the Angiogenic and Foreign Body Response to a 3D Printed Silicone-Based Macroencapsulation Device
Macroencapsulation systems have been developed to improve islet cell transplantation but can induce a foreign body response (FBR). The development of neovascularization adjacent to the device is vital for the survival of encapsulated islets and is a limitation for long-term device success. Previously we developed additive manufactured multi-scale porosity implants, which demonstrated a 2.5-fold increase in tissue vascularity and integration surrounding the implant when compared to a non-textured implant. In parallel to this, we have developed poly(ε-caprolactone-PEG-ε-caprolactone)-b-poly(L-lactide) multiblock copolymer microspheres containing VEGF, which exhibited continued release of bioactive VEGF for 4-weeks in vitro. In the present study, we describe the next step towards clinical implementation of an islet macroencapsulation device by combining a multi-scale porosity device with VEGF releasing microspheres in a rodent model to assess prevascularization over a 4-week period. An in vivo estimation of vascular volume showed a significant increase in vascularity (* p = 0.0132) surrounding the +VEGF vs. −VEGF devices, however, histological assessment of blood vessels per area revealed no significant difference. Further histological analysis revealed significant increases in blood vessel stability and maturity (** p = 0.0040) and vessel diameter size (*** p = 0.0002) surrounding the +VEGF devices. We also demonstrate that the addition of VEGF microspheres did not cause a heightened FBR. In conclusion, we demonstrate that the combination of VEGF microspheres with our multi-scale porous macroencapsulation device, can encourage the formation of significantly larger, stable, and mature blood vessels without exacerbating the FBR.
- 4 December 2021
- Published by MDPI AG in Pharmaceutics
- Vol. 13 (12) , 2077
Open AccessAssessing the Effects of VEGF Releasing Microspheres on the Angiogenic and Foreign Body Response to a 3D Printed Silicone-Based Macroencapsulation Device
Macroencapsulation systems have been developed to improve islet cell transplantation but can induce a foreign body response (FBR). The development of neovascularization adjacent to the device is vital for the survival of encapsulated islets and is a limitation for long-term device success. Previously we developed additive manufactured multi-scale porosity implants, which demonstrated a 2.5-fold increase in tissue vascularity and integration surrounding the implant when compared to a non-textured implant. In parallel to this, we have developed poly(ε-caprolactone-PEG-ε-caprolactone)-b-poly(L-lactide) multiblock copolymer microspheres containing VEGF, which exhibited continued release of bioactive VEGF for 4-weeks in vitro. In the present study, we describe the next step towards clinical implementation of an islet macroencapsulation device by combining a multi-scale porosity device with VEGF releasing microspheres in a rodent model to assess prevascularization over a 4-week period. An in vivo estimation of vascular volume showed a significant increase in vascularity (* p = 0.0132) surrounding the +VEGF vs. −VEGF devices, however, histological assessment of blood vessels per area revealed no significant difference. Further histological analysis revealed significant increases in blood vessel stability and maturity (** p = 0.0040) and vessel diameter size (*** p = 0.0002) surrounding the +VEGF devices. We also demonstrate that the addition of VEGF microspheres did not cause a heightened FBR. In conclusion, we demonstrate that the combination of VEGF microspheres with our multi-scale porous macroencapsulation device, can encourage the formation of significantly larger, stable, and mature blood vessels without exacerbating the FBR.
- Open Access
- 19 January 2021
- Published by American Chemical Society (ACS) in Molecular Pharmaceutics
- Vol. 18 (3) , 1247-1263
In Vitro and In Vivo Studies on HPMA-Based Polymeric Micelles Loaded with Curcumin
Curcumin-loaded polymeric micelles composed of poly(ethylene glycol)-b-poly(N-2-benzoyloxypropyl methacrylamide) (mPEG-b-p(HPMA-Bz)) were prepared to solubilize and improve the pharmacokinetics of curcumin. Curcumin-loaded micelles were prepared by a nanoprecipitation method using mPEG5kDa-b-p(HPMA-Bz) copolymers with varying molecular weight of the hydrophobic block (5.2, 10.0, and 17.1 kDa). At equal curcumin loading, micelles composed of mPEG5kDa-b-p(HPMA-Bz)17.1kDa showed better curcumin retention in both phosphate-buffered saline (PBS) and plasma at 37 °C than micelles based on block copolymers with smaller hydrophobic blocks. No change in micelle size was observed during 24 h incubation in plasma using asymmetrical flow field-flow fractionation (AF4), attesting to particle stability. However, 22–49% of the curcumin loading was released from the micelles during 24 h from formulations with the highest to the lowest molecular weight p(HPMA-Bz), respectively, in plasma. AF4 analysis further showed that the released curcumin was subsequently solubilized by albumin. In vitro analyses revealed that the curcumin-loaded mPEG5kDa-b-p(HPMA-Bz)17.1kDa micelles were internalized by different types of cancer cells, resulting in curcumin-induced cell death. Intravenously administered curcumin-loaded, Cy7-labeled mPEG5kDa-b-p(HPMA-Bz)17.1kDa micelles in mice at 50 mg curcumin/kg showed a long circulation half-life for the micelles (t1/2 = 42 h), in line with the AF4 results. In contrast, the circulation time of curcumin was considerably shorter than that of the micelles (t1/2α = 0.11, t1/2β = 2.5 h) but ∼5 times longer than has been reported for free curcumin (t1/2α = 0.02 h). The faster clearance of curcumin in vivo compared to in vitro studies can be attributed to the interaction of curcumin with blood cells. Despite the excellent solubilizing effect of these micelles, no cytostatic effect was achieved in neuroblastoma-bearing mice, possibly because of the low sensitivity of the Neuro2A cells to curcumin.
- 19 January 2021
- Published by American Chemical Society (ACS) in Molecular Pharmaceutics
- Vol. 18 (3) , 1247-1263
Open AccessIn Vitro and In Vivo Studies on HPMA-Based Polymeric Micelles Loaded with Curcumin
Curcumin-loaded polymeric micelles composed of poly(ethylene glycol)-b-poly(N-2-benzoyloxypropyl methacrylamide) (mPEG-b-p(HPMA-Bz)) were prepared to solubilize and improve the pharmacokinetics of curcumin. Curcumin-loaded micelles were prepared by a nanoprecipitation method using mPEG5kDa-b-p(HPMA-Bz) copolymers with varying molecular weight of the hydrophobic block (5.2, 10.0, and 17.1 kDa). At equal curcumin loading, micelles composed of mPEG5kDa-b-p(HPMA-Bz)17.1kDa showed better curcumin retention in both phosphate-buffered saline (PBS) and plasma at 37 °C than micelles based on block copolymers with smaller hydrophobic blocks. No change in micelle size was observed during 24 h incubation in plasma using asymmetrical flow field-flow fractionation (AF4), attesting to particle stability. However, 22–49% of the curcumin loading was released from the micelles during 24 h from formulations with the highest to the lowest molecular weight p(HPMA-Bz), respectively, in plasma. AF4 analysis further showed that the released curcumin was subsequently solubilized by albumin. In vitro analyses revealed that the curcumin-loaded mPEG5kDa-b-p(HPMA-Bz)17.1kDa micelles were internalized by different types of cancer cells, resulting in curcumin-induced cell death. Intravenously administered curcumin-loaded, Cy7-labeled mPEG5kDa-b-p(HPMA-Bz)17.1kDa micelles in mice at 50 mg curcumin/kg showed a long circulation half-life for the micelles (t1/2 = 42 h), in line with the AF4 results. In contrast, the circulation time of curcumin was considerably shorter than that of the micelles (t1/2α = 0.11, t1/2β = 2.5 h) but ∼5 times longer than has been reported for free curcumin (t1/2α = 0.02 h). The faster clearance of curcumin in vivo compared to in vitro studies can be attributed to the interaction of curcumin with blood cells. Despite the excellent solubilizing effect of these micelles, no cytostatic effect was achieved in neuroblastoma-bearing mice, possibly because of the low sensitivity of the Neuro2A cells to curcumin.
- Open Access
- 1 January 2021
- Published by Elsevier in European Journal of Pharmaceutics and Biopharmaceutics
- Vol. 158, 1-10
Post-loading of proangiogenic growth factors in PLGA microspheres
- 1 January 2021
- Published by Elsevier in European Journal of Pharmaceutics and Biopharmaceutics
- Vol. 158, 1-10
Open AccessPost-loading of proangiogenic growth factors in PLGA microspheres
- Open Access
- 1 December 2020
- Published by Elsevier in Journal of Controlled Release
- Vol. 328, 942-951
Correlation between in vitro stability and pharmacokinetics of poly(ε-caprolactone)-based micelles loaded with a photosensitizer
- 1 December 2020
- Published by Elsevier in Journal of Controlled Release
- Vol. 328, 942-951
Open AccessCorrelation between in vitro stability and pharmacokinetics of poly(ε-caprolactone)-based micelles loaded with a photosensitizer