1
|
Lefol L, Bawuah P, Zeitler J, Verin J, Danede F, Willart J, Siepmann F, Siepmann J. Drug release from PLGA microparticles can be slowed down by a surrounding hydrogel. Int J Pharm X 2023; 6:100220. [PMID: 38146325 PMCID: PMC10749250 DOI: 10.1016/j.ijpx.2023.100220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/23/2023] [Accepted: 11/25/2023] [Indexed: 12/27/2023] Open
Abstract
This study aimed to evaluate and better understand the potential impact that a layer of surrounding hydrogel (mimicking living tissue) can have on the drug release from PLGA microparticles. Ibuprofen-loaded microparticles were prepared with an emulsion solvent extraction/evaporation method. The drug loading was about 48%. The surface of the microparticles appeared initially smooth and non-porous. In contrast, the internal microstructure of the particles exhibited a continuous network of tiny pores. Ibuprofen release from single microparticles was measured into agarose gels and well-agitated phosphate buffer pH 7.4. Optical microscopy, scanning electron microscopy, differential scanning calorimetry, X-ray powder diffraction, and X-ray μCT imaging were used to characterize the microparticles before and after exposure to the release media. Importantly, ibuprofen release was much slower in the presence of a surrounding agarose gel, e.g., the complete release took two weeks vs. a few days in well agitated phosphate buffer. This can probably be attributed to the fact that the hydrogel sterically hinders substantial system swelling and, thus, slows down the related increase in drug mobility. In addition, in this particular case, the convective flow in agitated bulk fluid likely damages the thin PLGA layer at the microparticles' surface, giving the outer aqueous phase more rapid access to the inner continuous pore network: Upon contact with water, the drug dissolves and rapidly diffuses out through a continuous network of water-filled channels. Without direct surface access, most of the drug "has to wait" for the onset of substantial system swelling to be released.
Collapse
Affiliation(s)
- L.A. Lefol
- Univ. Lille, Inserm, CHU Lille, U1008, Lille F-59000, France
| | - P. Bawuah
- Univ. Cambridge, Department of Chemical Engineering and Biotechnology, Cambridge CB3 0AS, UK
| | - J.A. Zeitler
- Univ. Cambridge, Department of Chemical Engineering and Biotechnology, Cambridge CB3 0AS, UK
| | - J. Verin
- Univ. Lille, Inserm, CHU Lille, U1008, Lille F-59000, France
| | - F. Danede
- Univ. Lille, USTL UMET UMR CNRS 8207, Villeneuve d'Ascq F-59650, France
| | - J.F. Willart
- Univ. Lille, USTL UMET UMR CNRS 8207, Villeneuve d'Ascq F-59650, France
| | - F. Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, Lille F-59000, France
| | - J. Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, Lille F-59000, France
| |
Collapse
|
2
|
Bassand C, Siepmann F, Benabed L, Verin J, Freitag J, Charlon S, Soulestin J, Siepmann J. 3D printed PLGA implants: How the filling density affects drug release. J Control Release 2023; 363:1-11. [PMID: 37714435 DOI: 10.1016/j.jconrel.2023.09.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/22/2023] [Accepted: 09/10/2023] [Indexed: 09/17/2023]
Abstract
Different types of ibuprofen-loaded, poly (D,L lactic-co-glycolic acid) (PLGA)-based implants were prepared by 3D printing (Droplet Deposition Modeling). The theoretical filling density of the mesh-shaped implants was varied from 10 to 100%. Drug release was measured in agarose gels and in well agitated phosphate buffer pH 7.4. The key properties of the implants (and dynamic changes thereof upon exposure to the release media) were monitored using gravimetric measurements, optical microscopy, Differential Scanning Calorimetry, Gel Permeation Chromatography, and Scanning Electron Microscopy. Interestingly, drug release was similar for implants with 10 and 30% filling density, irrespective of the experimental set-up. In contrast, implants with 100% filling density showed slower release kinetics, and the shape of the release curve was altered in agarose gels. These observations could be explained by the existence (or absence) of a continuous aqueous phase between the polymeric filaments and the "orchestrating role" of substantial system swelling for the control of drug release. At lower filling densities, it is sufficient for the drug to be released from a single filament. In contrast, at high filling densities, the ensemble of filaments acts as a much larger (more or less homogeneous) polymeric matrix, and the average diffusion pathway to be overcome by the drug is much longer. Agarose gel (mimicking living tissue) hinders substantial PLGA swelling and delays the onset of the final rapid drug release phase. This improved mechanistic understanding of the control of drug release from PLGA-based 3D printed implants can help to facilitate the optimization of this type of advanced drug delivery systems.
Collapse
Affiliation(s)
- C Bassand
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - F Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - L Benabed
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - J Verin
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - J Freitag
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - S Charlon
- IMT Lille Douai, Dept Polymers & Composites Technol & Mech Engn, F-59500 Douai, France
| | - J Soulestin
- IMT Lille Douai, Dept Polymers & Composites Technol & Mech Engn, F-59500 Douai, France
| | - J Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France.
| |
Collapse
|
3
|
Bassand C, Benabed L, Charlon S, Verin J, Freitag J, Siepmann F, Soulestin J, Siepmann J. 3D printed PLGA implants: APF DDM vs. FDM. J Control Release 2023; 353:864-874. [PMID: 36464064 DOI: 10.1016/j.jconrel.2022.11.052] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Abstract
3D Printing offers a considerable potential for personalized medicines. This is especially true for customized biodegradable implants, matching the specific needs of each patient. Poly(lactic-co-glycolic acid) (PLGA) is frequently used as matrix former in biodegradable implants. However, yet relatively little is known on the technologies, which can be used for the 3D printing of PLGA implants. The aim of this study was to compare: (i) Arburg Plastic Freeforming Droplet Deposition Modeling (APF DDM), and (ii) Fused Deposition Modeling (FDM) to print mesh-shaped, ibuprofen-loaded PLGA implants. During APF DDM, individual drug-polymer droplets are deposited, fusing together to form filaments, which build up the implants. During FDM, continuous drug-polymer filaments are deposited to form the meshes. The implants were thoroughly characterized before and after exposure to phosphate buffer pH 7.4 using optical and scanning electron microscopy, GPC, DSC, drug release measurements and monitoring dynamic changes in the systems' dry & wet mass and pH of the bulk fluid. Interestingly, the mesh structures were significantly different, although the device design (composition & theoretical geometry) were the same. This could be explained by the fact that the deposition of individual droplets during APF DDM led to curved and rather thick filaments, resulting in a much lower mesh porosity. In contrast, FDM printing generated straight and thinner filaments: The open spaces between them were much larger and allowed convective mass transport during drug release. Consequently, most of the drug was already released after 4 d, when substantial PLGA set on. In the case of APF DDM printed implants, most of the drug was still entrapped at that time point and substantial polymer swelling transformed the meshes into more or less continuous PLGA gels. Hence, the diffusion pathways became much longer and ibuprofen release was controlled over 2 weeks.
Collapse
Affiliation(s)
- C Bassand
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - L Benabed
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - S Charlon
- IMT Lille Douai, École Nationale Supérieure Mines-Télécom Lille Douai, Materials & Processes Center, Cité Scientifique, Villeneuve d'Ascq Cedex, France
| | - J Verin
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - J Freitag
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - F Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - J Soulestin
- IMT Lille Douai, École Nationale Supérieure Mines-Télécom Lille Douai, Materials & Processes Center, Cité Scientifique, Villeneuve d'Ascq Cedex, France
| | - J Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France.
| |
Collapse
|
4
|
Bassand C, Benabed L, Freitag J, Verin J, Siepmann F, Siepmann J. How bulk fluid renewal can affect in vitro drug release from PLGA implants: Importance of the experimental set-up. Int J Pharm X 2022; 4:100131. [PMID: 36189458 PMCID: PMC9519472 DOI: 10.1016/j.ijpx.2022.100131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/30/2022] [Accepted: 09/16/2022] [Indexed: 11/08/2022] Open
Abstract
The aim of this study was to better understand the potential impact of partial vs. complete renewal of the bulk fluid during drug release measurements from poly (lactic-co-glycolic acid) (PLGA)-based implants. A “standard experimental set-up”, in which the implants were directly exposed to well agitated phosphate buffer pH 7.4 was used, as well as set-ups, in which the implants were embedded within agarose hydrogels (mimicking living tissue). The gels were exposed to well agitated phosphate buffer pH 7.4. Ibuprofen-loaded implants were prepared by hot melt extrusion. The systems were thoroughly characterized before and during drug release by optical and scanning electron microscopy, gravimetric analysis, pH and solubility measurements as well as gel permeation chromatography. The bulk fluid was either completely or partially replaced by fresh medium at each sampling time point. In all cases, sink conditions were provided in the agitated bulk fluids throughout the experiments. Interestingly, the agarose set-ups did not show any noteworthy impact of the bulk fluid sampling volume on the observed drug release patterns, whereas complete fluid renewal in the “standard set-up” led to accelerated drug release. This could be explained by the considerable fragility of the implants once substantial polymer swelling set on, transforming them into PLGA gels: Complete fluid renewal caused partial disintegration and damage of the highly swollen systems, decreasing the lengths of the diffusion pathways for the drug. The mechanical stress is very much reduced at low sampling volumes, or if the implants are embedded within agarose gels. Thus, great care must be taken when defining the conditions for in vitro drug release measurements from PLGA-based implants: Once substantial system swelling sets on, the devices become highly fragile.
Collapse
|
5
|
Bassand C, Benabed L, Verin J, Danede F, Lefol L, Willart J, Siepmann F, Siepmann J. Hot melt extruded PLGA implants loaded with ibuprofen: How heat exposure alters the physical drug state. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
6
|
Wanselius M, Searle S, Rodler A, Tenje M, Abrahmsén-Alami S, Hansson P. Microfluidics Platform for Studies of Peptide – Polyelectrolyte Interaction. Int J Pharm 2022; 621:121785. [DOI: 10.1016/j.ijpharm.2022.121785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/12/2022] [Accepted: 04/26/2022] [Indexed: 02/01/2023]
|
7
|
Bock F, Bøtker JP, Larsen SW, Lu X, Østergaard J. Methodological Considerations in Development of UV Imaging for Characterization of Intra-Tumoral Injectables Using cAMP as a Model Substance. Int J Mol Sci 2022; 23:ijms23073599. [PMID: 35408971 PMCID: PMC8998202 DOI: 10.3390/ijms23073599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/17/2022] [Accepted: 03/23/2022] [Indexed: 12/19/2022] Open
Abstract
A UV imaging release-testing setup comprising an agarose gel as a model for tumorous tissue was developed. The setup was optimized with respect to agarose concentration (0.5% (w/v)), injection procedure, and temperature control. A repeatable injection protocol was established allowing injection into cavities with well-defined geometries. The effective resolution of the SDi2 UV imaging system is 30-80 µm. The linear range of the imaging system is less than that of typical spectrophotometers. Consequently, non-linear cAMP calibration curves were applied for quantification at 280 nm. The degree of deviation from Beer's law was affected by the background absorbance of the gel matrix. MATLAB scripts provided hitherto missing flexibility with respect to definition and utilization of quantification zones, contour lines facilitating visualization, and automated, continuous data analysis. Various release patterns were observed for an aqueous solution and in situ forming Pluronic F127 hydrogel and PLGA implants containing cAMP as a model for STING ligands. The UV imaging and MATLAB data analysis setup constituted a significant technical development in terms of visualizing behavior for injectable formulations intended for intra-tumoral delivery, and, thereby, a step toward establishment of a bio-predictive in vitro release-testing method.
Collapse
Affiliation(s)
- Frederik Bock
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark; (F.B.); (J.P.B.); (S.W.L.)
| | - Johan Peter Bøtker
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark; (F.B.); (J.P.B.); (S.W.L.)
| | - Susan Weng Larsen
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark; (F.B.); (J.P.B.); (S.W.L.)
| | - Xujin Lu
- Bristol Myers Squibb Company, Drug Product Development, 1 Squibb Drive, New Brunswick, NJ 08901, USA;
| | - Jesper Østergaard
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark; (F.B.); (J.P.B.); (S.W.L.)
- Correspondence: ; Tel.: +45-35336138
| |
Collapse
|
8
|
How agarose gels surrounding PLGA implants limit swelling and slow down drug release. J Control Release 2022; 343:255-266. [PMID: 35085697 DOI: 10.1016/j.jconrel.2022.01.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 01/12/2022] [Accepted: 01/19/2022] [Indexed: 11/20/2022]
Abstract
The aim of this study was to better understand to which extent and in which way the presence of an agarose gel (mimicking living tissue) around a PLGA [poly(lactic-co-glycolic acid)] implant affects the resulting drug release kinetics. Ibuprofen-loaded implants were prepared by hot melt extrusion. Drug release was measured upon exposure to phosphate buffer pH 7.4 in Eppendorf tubes, as well as upon inclusion into an agarose gel which was exposed to phosphate buffer pH 7.4 in an Eppendorf tube or in a transwell plate. Dynamic changes in the implants' dry & wet mass and dimensions were monitored gravimetrically and by optical macroscopy. Implant erosion and polymer degradation were observed by SEM and GPC. Different pH indicators were used to measure pH changes in the bulk fluids, gels and within the implants during drug release. Ibuprofen release was bi-phasic in all cases: A zero order release phase (~20% of the dose) was followed by a more rapid, final drug release phase. Interestingly, the presence of the hydrogel delayed the onset of the 2nd release phase. This could be attributed to the sterical hindrance of implant swelling: After a certain lag time, the degrading PLGA matrix becomes sufficiently hydrophilic and mechanically instable to allow for the penetration of substantial amounts of water into the system. This fundamentally changes the conditions for drug release: The latter becomes much more mobile and is more rapidly released. A gel surrounding the implant mechanically hinders system swelling and, thus, slows down drug release. These observations also strengthen the hypothesis of the "orchestrating" role of PLGA swelling for the control of drug release and can help developing more realistic in vitro release set-ups.
Collapse
|
9
|
An in vitro gel-based system for characterizing and predicting the long-term performance of PLGA in situ forming implants. Int J Pharm 2021; 609:121183. [PMID: 34653562 DOI: 10.1016/j.ijpharm.2021.121183] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/03/2021] [Accepted: 10/08/2021] [Indexed: 10/20/2022]
Abstract
In situ forming implants are exposed to an extracellular matrix resembling a gel rather than aqueous solution upon subcutaneous administration. The aim of study was to develop a gel-based release testing system for characterizing the long-term in vitro behavior of in situ forming implants. The gel-based system consisted of an agarose gel mimicking the subcutaneous injection site and a receiver layer comprising phosphate buffer. Poly(D,L-lactide-co-glycolide) in situ forming implants containing leuprolide acetate as the model peptide and N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO) or triacetin as co-solvent were investigated. The gel-based release testing system discriminated between the formulations. Accelerated release data obtained at elevated temperatures were able to predict real-time release applying the Arrhenius equation. Monitoring of the microenvironmental pH of the implants was performed by UV-Vis imaging in the gel-based system at 50 °C. A pH drop (from pH 7.4 to 6.7 for the NMP and DMSO implants, to pH 5.5 for the triacetin implants) within the first day was observed, followed by an increase to pH ∼7.4. The gel-based system coupled with UV imaging offered opportunity for detailed evaluation and prediction of the in vitro performance of long-acting injectables, facilitating future development of in situ depot forming delivery systems.
Collapse
|
10
|
Simulate SubQ: The Methods and the Media. J Pharm Sci 2021; 112:1492-1508. [PMID: 34728176 DOI: 10.1016/j.xphs.2021.10.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/21/2022]
Abstract
For decades, there has been a growing interest in injectable subcutaneous formulations to improve the absorption of drugs into the systemic circulation and to prolong their release over a longer period. However, fluctuations in the blood plasma levels together with bioavailability issues often limit their clinical success. This warrants a closer look at the performance of long-acting depots, for example, and their dependence on the complex interplay between the dosage form and the physiological microenvironment. For this, biopredictive performance testing is used for a thorough understanding of the biophysical processes affecting the absorption of compounds from the injection site in vivo and their simulation in vitro. In the present work, we discuss in vitro methodologies including methods and media developed for the subcutaneous route of administration on the background of the most relevant absorption mechanisms. Also, we highlight some important knowledge gaps and shortcomings of the existing methodologies to provide the reader with a better understanding of the scientific evidence underlying these models.
Collapse
|
11
|
Brown B, Ward A, Fazili Z, Østergaard J, Asare-Addo K. Application of UV dissolution imaging to pharmaceutical systems. Adv Drug Deliv Rev 2021; 177:113949. [PMID: 34461199 DOI: 10.1016/j.addr.2021.113949] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/11/2021] [Accepted: 08/23/2021] [Indexed: 12/19/2022]
Abstract
UV-vis spectrometry is widely used in the pharmaceutical sciences for compound quantification, alone or in conjunction with separation techniques, due to most drug entities possessing a chromophore absorbing light in the range 190-800 nm. UV dissolution imaging, the scope of this review, generates spatially and temporally resolved absorbance maps by exploiting the UV absorbance of the analyte. This review aims to give an introduction to UV dissolution imaging and its use in the determination of intrinsic dissolution rates and drug release from whole dosage forms. Applications of UV imaging to non-oral formulations have started to emerge and are reviewed together with the possibility of utilizing UV imaging for physical chemical characterisation of drug substances. The benefits of imaging drug diffusion and transport processes are also discussed.
Collapse
|
12
|
Kozak J, Rabiskova M, Lamprecht A. Muscle Tissue as a Surrogate for In Vitro Drug Release Testing of Parenteral Depot Microspheres. AAPS PharmSciTech 2021; 22:119. [PMID: 33782794 PMCID: PMC8007510 DOI: 10.1208/s12249-021-01965-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/14/2021] [Indexed: 12/19/2022] Open
Abstract
Despite the importance of drug release testing of parenteral depot formulations, the current in vitro methods still require ameliorations in biorelevance. We have investigated here the use of muscle tissue components to better mimic the intramuscular administration. For convenient handling, muscle tissue was used in form of a freeze-dried powder, and a reproducible process of incorporation of tested microspheres to an assembly of muscle tissue of standardized dimensions was successfully developed. Microspheres were prepared from various grades of poly(lactic-co-glycolic acid) (PLGA) or ethyl cellulose, entrapping flurbiprofen, lidocaine, or risperidone. The deposition of microspheres in the muscle tissue or addition of only isolated lipids into the medium accelerated the release rate of all model drugs from microspheres prepared from ester-terminated PLGA grades and ethyl cellulose, however, not from the acid-terminated PLGA grades. The addition of lipids into the release medium increased the solubility of all model drugs; nonetheless, also interactions of the lipids with the polymer matrix (ad- and absorption) might be responsible for the faster drug release. As the in vivo drug release from implants is also often faster than in simple buffers in vitro, these findings suggest that interactions with the tissue lipids may play an important role in these still unexplained observations.
Collapse
Affiliation(s)
- Jan Kozak
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Straße 3, 53121, Bonn, Germany
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Akademika Heyrovskeho 1203/8, 500 05, Hradec Kralove, Czech Republic
| | - Miloslava Rabiskova
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Akademika Heyrovskeho 1203/8, 500 05, Hradec Kralove, Czech Republic
| | - Alf Lamprecht
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Straße 3, 53121, Bonn, Germany.
| |
Collapse
|
13
|
|