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  • 1.
    Andersson, Helene
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience. Chalmers University of Technology, Sweden.
    Häbel, Henrike
    Chalmers University of Technology, Sweden.
    Olsson, Anna
    Chalmers University of Technology, Sweden.
    Sandhagen, Sofie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience. Chalmers University of Technology, Sweden.
    von Corswant, Christian
    AstraZeneca, Sweden.
    Hjärtstam, Johan
    AstraZeneca, Sweden.
    Persson, Michael
    Chalmers University of Technology, Sweden; AkzoNobel, Sweden.
    Stading, Mats
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience, Structure Design. Chalmers University of Technology, Sweden.
    Larsson, Anette
    Chalmers University of Technology, Sweden.
    The influence of the molecular weight of the water-soluble polymer on phase-separated films for controlled release2016In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 511, no 1, p. 223-235Article in journal (Refereed)
    Abstract [en]

    Hydroxypropyl cellulose (HPC) and ethyl cellulose (EC) can be used for extended release coatings, where the water-soluble HPC may act as a pore former. The aim was to investigate the effect of the molecular weight of HPC on the microstructure and mass transport in phase-separated freestanding EC/HPC films with 30% w/w HPC. Four different HPC grades were used, with weight averaged molecular weights (Mw) of 30.0 (SSL), 55.0 (SL), 83.5 (L) and 365 (M) kg/mol. Results showed that the phase-separated structure changed from HPC-discontinuous to bicontinuous with increasing Mw of HPC. The film with the lowest Mw HPC (SSL) had unconnected oval-shaped HPC-rich domains, leaked almost no HPC and had the lowest water permeability. The remaining higher Mw films had connected complex-shaped pores, which resulted in higher permeabilities. The highest Mw film (M) had the smallest pores and very slow HPC leakage, which led to a slow increase in permeability. Films with grade L and SL released most of their HPC, yet the permeability of the L film was three times higher due to greater pore connectivity. It was concluded that the phase-separated microstructure, the level of pore percolation and the leakage rate of HPC will be affected by the choice of HPC Mw grade used in the film and this will in turn have strong impact on the film permeability.

  • 2.
    Badal Tejedor, Maria
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor. KTH Royal Institute of Technology, Sweden.
    Nordgren, Niklas
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor.
    Schuleit, Michael
    Novartis Pharma AG, Switzerland.
    Rutland, Mark W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor. KTH Royal Institute of Technology, Sweden.
    Millqvist-Fureby, Anna
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor.
    Tablet mechanics depend on nano and micro scale adhesion, lubrication and structure2015In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 486, no 1-2, p. 315-323Article in journal (Refereed)
    Abstract [en]

    Tablets are the most convenient form for drug administration. However, despite the ease of manufacturing problems such as powder adhesion occur during the production process. This study presents surface and structural characterization of tablets formulated with commonly used excipients (microcrystalline cellulose (MCC), lactose, mannitol, magnesium (Mg) stearate) pressed under different compaction conditions. Tablet surface analyses were performed with scanning electron microscopy (SEM), profilometry and atomic force microscopy (AFM). The mechanical properties of the tablets were evaluated with a tablet hardness test. Local adhesion detected by AFM decreased when Mg stearate was present in the formulation. Moreover, the tablet strength of plastically deformable excipients such as MCC was significantly decreased after addition of Mg stearate. Combined these facts indicate that Mg stearate affects the particle-particle bonding and thus elastic recovery. The MCC excipient also displayed the highest hardness which is characteristic for a highly cohesive material. This is discussed in the view of the relatively high adhesion found between MCC and a hydrophilic probe at the nanoscale using AFM. In contrast, the tablet strength of brittle materials like lactose and mannitol is unaffected by Mg stearate. Thus fracture occurs within the excipient particles and not at particle boundaries, creating new surfaces not previously exposed to Mg stearate. Such uncoated surfaces may well promote adhesive interactions with tools during manufacture.

  • 3.
    Badal Tejedor, Maria
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation. KTH Royal Institute of Technology, Sweden.
    Pazesh, Samaneh
    Uppsala University, Sweden.
    Nordgren, Niklas
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Schuleit, Micheal
    Novartis Pharma AG, Switzerland.
    Rutland, Mark W.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation. KTH Royal Institute of Technology, Sweden.
    Alderborn, Göran
    Uppsala University, Sweden.
    Millqvist-Fureby, Anna
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Milling induced amorphisation and recrystallization of α-lactose monohydrate2018In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 537, no 1-2, p. 140-147Article in journal (Refereed)
    Abstract [en]

    Preprocessing of pharmaceutical powders is a common procedure to condition the materials for a better manufacturing performance. However, such operations may induce undesired material properties modifications when conditioning particle size through milling, for example. Modification of both surface and bulk material structure will change the material properties, thus affecting the processability of the powder. Hence it is essential to control the material transformations that occur during milling. Topographical and mechanical changes in surface properties can be a preliminary indication of further material transformations. Therefore a surface evaluation of the α-lactose monohydrate after short and prolonged milling times has been performed. Unprocessed α-lactose monohydrate and spray dried lactose were evaluated in parallel to the milled samples as reference examples of the crystalline and amorphous lactose structure. Morphological differences between unprocessed α-lactose, 1 h and 20 h milled lactose and spray dried lactose were detected from SEM and AFM images. Additionally, AFM was used to simultaneously characterize particle surface amorphicity by measuring energy dissipation. Extensive surface amorphicity was detected after 1 h of milling while prolonged milling times showed only a moderate particle surface amorphisation. Bulk material characterization performed with DSC indicated a partial amorphicity for the 1 h milled lactose and a fully amorphous thermal profile for the 20 h milled lactose. The temperature profiles however, were shifted somewhat in the comparison to the amorphous reference, particularly after extended milling, suggesting a different amorphous state compared to the spray-dried material. Water loss during milling was measured with TGA, showing lower water content for the lactose amorphized through milling compared to spray dried amorphous lactose. The combined results suggest a surface-bulk propagation of the amorphicity during milling in combination with a different amorphous structural conformation to that of the amorphous spray dried lactose. The hardened surface may be due to either surface crystallization of lactose or to formation of a low-water glass transition.

  • 4.
    Bannow, J.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Benjamins, Jan-Willem
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Wohlert, J.
    KTH Royal Institute of Technology, Sweden.
    Löbmann, K.
    University of Copenhagen, Denmark.
    Svagan, A. J.
    KTH Royal Institute of Technology, Sweden.
    Solid nanofoams based on cellulose nanofibers and indomethacin—the effect of processing parameters and drug content on material structure2017In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 526, no 1-2, p. 291-299Article in journal (Refereed)
    Abstract [en]

    The unique colloidal properties of cellulose nanofibers (CNF), makes CNF a very interesting new excipient in pharmaceutical formulations, as CNF in combination with some poorly-soluble drugs can create nanofoams with closed cells. Previous nanofoams, created with the model drug indomethacin, demonstrated a prolonged release compared to films, owing to the tortuous diffusion path that the drug needs to take around the intact air-bubbles. However, the nanofoam was only obtained at a relatively low drug content of 21 wt% using fixed processing parameters. Herein, the effect of indomethacin content and processing parameters on the foaming properties was analysed. Results demonstrate that a certain amount of dissolved drug is needed to stabilize air-bubbles. At the same time, larger fractions of dissolved drug promote coarsening/collapse of the wet foam. The pendant drop/bubble profile tensiometry was used to verify the wet-foam stability at different pHs. The pH influenced the amount of solubilized drug and the processing-window was very narrow at high drug loadings. The results were compared to real foaming-experiments and solid state analysis of the final cellular solids. The parameters were assembled into a processing chart, highlighting the importance of the right combination of processing parameters (pH and time-point of pH adjustment) in order to successfully prepare cellular solid materials with up to 46 wt% drug loading.

  • 5.
    Barreto-Henriksson, H.
    et al.
    Sahlgrenska Hospital, Sweden.
    Llorente, M.
    Chalmers University of Technology, Sweden.
    Larsson, A.
    Chalmers University of Technology, Sweden.
    Brisby, H.
    University of Gothenburg, Sweden.
    Gold, J.
    Chalmers University of Technology, Sweden.
    Schuster, Erik
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience. Chalmers University of Technology, Sweden.
    Ström, Anna
    Chalmers University of Technology, Sweden.
    Determination of mechanical and rheological properties of a cell-loaded peptide gel during ECM production2019In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 563, p. 437-444Article in journal (Refereed)
    Abstract [en]

    The development of an injectable biomaterial that supports cell survival and maintains or promotes nucleus pulposus (NP) phenotype could aid delivery of cells to degenerated NPs causing low back pain. Mesenchymal cells were loaded and grown in a synthetic peptide gel, PuraMatrix ® . Cells were observed within the gels over 0–28 days, and accumulation of glycosaminoglycans were detected by histological staining. The mechanical properties of the cell-loaded constructs, and the change of the mechanical properties were studied using stress relaxation of the gels under compression and confinement. The PuraMatrix ® gel was shown to relax fast on compression indicating that the fluid could easily flow out of the gel, and thus indicating the presence of large pores/voids. The presence of these pores/voids was further supported by high mobility of dextran molecules, determined using fluorescence recovery after photo bleaching. The stress required to deform the cell-loaded constructs to a specific strain increases at day 21, at which point the presence of glycosaminoglycans within the cell-loaded constructs was also observed. The results provide evidence of changes in mechanical properties of the PuraMatrix ® matrix upon excretion of the extracellular matrix by the

  • 6.
    Boge, Lucas
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Umerska, Anita
    INSERM U 1066, France ; Université Angers, France.
    Matougui, Nada
    INSERM U 1066, France ; Université Angers,France.
    Bysell, Helena
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Ringstad, Lovisa
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Davoudi, Mina
    Lund University, Sweden.
    Eriksson, Jonny
    Uppsala University, Sweden.
    Edwards, Katarina
    Uppsala University, Sweden.
    Andersson, Martin
    Chalmers University of Technology, Sweden.
    Cubosomes post-loaded with antimicrobial peptides: Characterization, bactericidal effect and proteolytic stability2017In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 526, no 1-2, p. 400-412Article in journal (Refereed)
    Abstract [en]

    Novel antibiotics, such as antimicrobial peptides (AMPs), have recently attended more and more attraction. In this work, dispersed cubic liquid crystalline gel (cubosomes) was used as drug delivery vehicles for three AMPs (AP114, DPK-060 and LL-37). Association of peptides onto cubosomes was studied at two cubosome/peptide ratios using high performance liquid chromatography, ζ-potential and circular dichroism measurements. AMPs impact on the cubosome structure was investigated using small angle x-ray scattering and cryogenic transmission electron microscopy. The antimicrobial effect of the AMP loaded cubosomes was studied in vitro by minimum inhibitory concentration and time-kill assays. Proteolytic protection was investigated by incubating the formulations with two elastases and the antimicrobial effect after proteolysis was studied using radial diffusion assay. Different association efficacy onto the cubosomes was observed among the AMPs, with LL-37 showing greatest association (>60%). AP114 loaded cubosomes displayed a preserved antimicrobial effect, whereas for LL-37 the broad spectrum bacterial killing was reduced to only comprise Gram-negative bacteria. Interestingly, DPK-060 loaded cubosomes showed a slight enhanced effect against S. aureus and E. coli strains. Moreover, the cubosomes were found to protect LL-37 from proteolytic degradation, resulting in a significantly better bactericidal effect after being subjected to elastase, compared to unformulated peptide.

  • 7.
    Colombo, Stefan
    et al.
    Uppsala University, Sweden.
    Brisander, Magnus
    XSpray Microparticles AB, Sweden.
    Haglöf, Jakob
    Uppsala University, Sweden.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik.
    Andersson, Per
    XSpray Microparticles AB, Sweden.
    Østergaard, Jesper
    University of Copenhagen, Denmark.
    Malmsten, Martin
    Uppsala University, Sweden.
    Matrix effects in nilotinib formulations with pH-responsive polymer produced by carbon dioxide-mediated precipitation2015In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 494, no 1, p. 205-217, article id 15114Article in journal (Refereed)
    Abstract [en]

    Factors determining the pH-controlled dissolution kinetics of nilotinib formulations with the pH-titrable polymer hydroxypropyl methylcellulose phthalate, obtained by carbon dioxide-mediated precipitation, were mechanistically examined in acid and neutral environment. The matrix effect, modulating the drug dissolution, was characterized with a battery of physicochemical methodologies, including ToF-SIMS for surface composition, SAXS/WAXS and modulated DSC for crystallization characterization, and simultaneous UV-imaging and Raman spectroscopy for monitoring the dissolution process in detail. The hybrid particle formulations investigated consisted of amorphous nilotinib embedded in a polymer matrix in single continuous phase, displaying extended retained amorphicity also under wet conditions. It was demonstrated by Raman and FTIR spectroscopy that the efficient drug dispersion and amorphization in the polymer matrix were mediated by hydrogen bonding between the drug and the phthalate groups on the polymer. Simultaneous Raman and UV-imaging studies of the effect of drug load on the swelling and dissolution of the polymer matrix revealed that high nilotinib load prevented matrix swelling on passage from acid to neutral pH, thereby preventing re-precipitation and re-crystallization of incorporated nilotinib. These findings provide a mechanistic foundation of formulation development of nilotinib and other protein kinase inhibitors, which are now witnessing an intense therapeutic and industrial attention due to the difficulty in formulating these compounds so that efficient oral bioavailability is reached.

  • 8. Elversson, J
    et al.
    Millqvist-Fureby, A
    YKI – Ytkemiska institutet.
    Aqueous two-phase system as a formulation concept for spray-dried protein2005In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 294, p. 73-87Article in journal (Refereed)
    Abstract [en]

    This study investigates to what extent an aqueous two-phase system (ATPS) can encapsulate and protect the secondary structure of a protein during spray drying. The ATPSs contained polyvinyl alcohol (PVA) and dextran solutions, in different proportions. A model protein, bovine serum albumin (BSA) and, in some experiments, trehalose were added to the ATPS prior to spray drying. Electron spectroscopy for chemical analysis (ESCA), differential scanning calorimetry (DSC), UV spectrophotometry, size exclusion high-performance liquid chromatography (SEC-HPLC) and Fourier transform infrared spectroscopy (FTIR) were used for analysis of solid and reconstituted samples. The anticipated function of the ATPS was to improve the stability of the protein by preventing interactions with the air–liquid interface during drying and by improving the encapsulation of the protein in the dried powder. BSA was found to preferentially partition to the dextran phase and in the absence of PVA, BSA dominated the powder surface. In samples containing PVA, the polymer mainly covered the powder surface, even though the dextran-rich phase was continuous, thus preventing protein surface interactions and providing improved encapsulation. However, PVA was found to cause partial loss of the native structure of BSA although the protein was well encapsulated during spray drying

  • 9. Elversson, J
    et al.
    Millqvist-Fureby, A
    YKI – Ytkemiska institutet.
    In situ coating - An approach for particle modification and encapsulation of proteins during spray-drying2006In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 323, p. 52-63Article in journal (Refereed)
    Abstract [en]

    In this paper, we present a method for in situ coating of individual protein particles in a respirable size. The aim of the coating was to influence the particle/powder properties, and to reduce or prevent surface-induced conformational changes of the protein, during spray-drying, which was the method used for simultaneously preparing and coating particles. The investigated formulations included bovine serum albumin (BSA), trehalose and either of the two non-ionic polymers, hydroxypropyl methylcellulose (HPMC) and poly(ethylene oxide)–poly(propylene oxide) triblock co-polymer (Poloxamer 188). Complete protein coating as measured by electron spectroscopy for chemical analysis (ESCA) was achieved at a polymer concentration of approximately 1% of the total solids weight, and could be predicted from the dynamic surface tension at the air/water interface, as measured by the pendant drop method. Further, particle properties such as: size, dissolution time, powder flowability, and apparent particle density, as measured by gas pycnometry, were affected by the type and concentration of the polymer. In addition, the particle surface morphology could possibly be correlated to the surface elasticity of the droplet surface during drying. Moreover, an extensive investigation (Fourier transform infrared spectroscopy, circular dichroism and size exclusion chromatography) of the structural effects of protein encapsulated in a polymeric coating suggested that in situ coating provide particulate formulations with preserved native conformation and with a high stability during rehydration

  • 10. Marucci, M.
    et al.
    Andersson, Helene
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Hjärtstam, J.
    von Corswant, C.
    Baderstedt, J.
    Stading, Mats
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    New insights on how to adjust the release profile from coated pellets by varying the molecular weight of ethyl cellulose in the coating film2013In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 458, no 1, p. 218-223Article in journal (Refereed)
    Abstract [en]

    The major aims of this work were to study the effect of the molecular weight (Mw) of ethyl cellulose (EC) on the drug release profile from metoprolol succinate pellets coated with films comprising EC and hydroxypropyl cellulose (HPC) with a weight ratio of 70:30, and to understand the mechanisms behind the different release profiles. A broad range of Mws was used, and the kinetics of drug release and HPC leaching followed. The higher the Mw of EC, the slower the HPC leaching and the drug release processes. Drug release occurred by diffusion through the pores created in the coating by the HPC leaching. A novel method was used to explain the differences in the release profiles: the effective diffusion coefficient (De) of the drug in the coating film was determined using a mechanistic model and compared to the amount of HPC leached. A linear dependence was found between De and the amount of HPC leached and, importantly, the value of the proportionality constant decreased with increasing Mw of EC. This suggests that the Mw of EC affects the drug release profile by affecting the phase separated microstructure of the coating and the hindrance it imparts to drug diffusion. © 2013 Elsevier B.V.

  • 11.
    Matougui, Nada
    et al.
    Inserm, France.
    Boge, Lukas
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science.
    Groo, Anne-Claire
    Inserm, France.
    Umerska, Anita
    Inserm, France.
    Ringstad, Lovisa
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science.
    Bysell, Helena
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science.
    Saulnier, Patrick
    Inserm, France; CHU Angers, France.
    Lipid-based nanoformulations for peptide delivery2016In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 502, no 1-2, p. 80-97Article, review/survey (Refereed)
    Abstract [en]

    Nanoformulations have attracted a lot of attention because of their size-dependent properties. Among the array of nanoformulations, lipid nanoformulations (LNFs) have evoked increasing interest because of the advantages of their high degree of biocompatibility and versatility. The performance of lipid nanoformulations is greatly influenced by their composition and structure. Therapeutic peptides represent a growing share of the pharmaceutical market. However, the main challenge for their development into commercial products is their inherent physicochemical and biological instability. Important peptides such as insulin, calcitonin and cyclosporin A have been incorporated into LNFs. The association or encapsulation of peptides within lipid-based carriers has shown to protect the labile molecules against enzymatic degradation. This review describes strategies used for the formulation of peptides and some methods used for the assessment of association efficiency. The advantages and drawbacks of such carriers are also described.

  • 12.
    Millqvist-Fureby, A
    et al.
    YKI – Ytkemiska institutet.
    Malmsten, M
    YKI – Ytkemiska institutet.
    Bergenståhl, B
    YKI – Ytkemiska institutet.
    Spray-drying of trypsin – Surface characterisation and activity preservation1999In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 188, p. 243-253Article in journal (Refereed)
    Abstract [en]

    In the present study trypsin mixed with various carbohydrates, i.e. lactose, sucrose, mannitol, a-cyclodextrin and dextrin, was spray-dried in order to investigate the effects of spray-drying on this enzyme, with particular emphasis on the effects of interactions between trypsin and the surface formed during spray-drying. The protein was strongly over-represented at the surface of the powder particles, the surface coverage ranging from 10 to 65%, depending on the amount of trypsin in the solids (0.2-5%). This indicates that the protein adsorbs at the air/liquid interface of the spray-droplets, and that this surface is largely preserved also after drying. The surface concentration of protein in the spray-dried powders could be controlled by adding a surfactant to the mixture before drying, since the surfactant adsorbs preferentially at the air/liquid interface of the spray droplets, thus expelling protein from the surface. In general, the residual activity of trypsin in these non-optimised formulations was 90% or higher, and in no case less than 82%. It was found that the loss of activity could partly be explained by inactivation of the protein adsorbed at the surface. For mannitol and sucrose, however, the level of inactivation was higher than could be explained by surface inactivation alone, and additional mechanisms must also be considered.

  • 13.
    Millqvist-Fureby, A
    et al.
    YKI – Ytkemiska institutet.
    Malmsten, M
    YKI – Ytkemiska institutet.
    Bergenståhl, B
    YKI – Ytkemiska institutet.
    Surface characterisation of freeze-dried protein/carbohydrate mixtures1999In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 191, p. 103-114Article in journal (Refereed)
    Abstract [en]

    In the present investigation freeze-drying of proteins (BSA or trypsin) together with various carbohydrates, i.e. lactose, sucrose, mannitol, a-cyclodextrin and dextrin, has been studied with particular emphasis on the surface composition of the freeze-dried powders. The proteins were found to be over-represented on the powder surface as compared to the bulk concentration of protein. The mechanism behind the surface accumulation is believed to be that proteins adsorb preferentially over carbohydrates to the ice/liquid interface in the frozen sample. The degree of surface accumulation depended on the carbohydrate used, and was increased in annealed samples compared to reference samples. The activity of trypsin was fairly preserved well (58-90%) in the freeze-dried powders, but depended on the carbohydrate excipient, whilst the surface composition had little effect on the activity. The activity preservation was improved when the protein concentration was raised from 1% to 10% in the solids. The surface composition of powders containing mixtures of mannitol and dextrin as excipients depended on the ratio between the two carbohydrates, with the lowest surface coverage of protein obtained in 50/50 mixtures.

  • 14.
    Moore, Helene A.
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience. Chalmers University of Technology, Sweden.
    Marucci, MariaGrazia
    Chalmers University of Technology, Sweden ; AstraZeneca R&D Gothenburg, Sweden.
    Härdelin, Linda
    Chalmers University of Technology, Sweden.
    Hjärtstam, Johan
    Chalmers University of Technology, Sweden ; AstraZeneca R&D Gothenburg, Sweden.
    Stading, Mats
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience. Chalmers University of Technology, Sweden.
    von Corswant, Christian
    Chalmers University of Technology, Sweden ; AstraZeneca R&D Gothenburg, Sweden.
    Larsson, Anette
    Chalmers University of Technology, Sweden.
    New insights on the influence of manufacturing conditions and molecular weight on phase-separated films intended for controlled release2018In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 536, no 1, p. 261-271Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to investigate how manufacturing conditions influence phase-separated films of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC) with different molecular weights of HPC. Two HPC grades, SSL and M, with weight average molecular weights (Mw) of 30 × 103 g/mol and 365 × 103 g/mol, respectively, were combined with EC 10 cps (70:30 w/w EC/HPC) and spray-coated from ethanol solutions onto a rotating drum under well-controlled process conditions. Generally, a low spray rate resulted in a more rapid film drying process and, consequently, in smaller HPC-rich domains in the phase-separated film structure. For EC/HPC films with the low Mw HPC (SSL) the most rapid drying process resulted in a shift from a HPC-discontinuous to a partly bicontinuous structure and an increase in the permeability for water. In contrast, films containing the high Mw HPC (M) all showed bicontinuous structures, which resulted in overall higher water permeabilities and polymer release compared to the low Mw films. Interestingly, a maximum in permeability was observed for the high Mw films at intermediate spray rates. Below this spray rate the permeability decreased due to a lower amount of polymer released and at higher spray rates, the permeability decreased due to a loss of pore connectivity (or increased tortuosity). To conclude, this study shows that different Mw systems of EC/HPC can respond differently to variations in manufacturing conditions.

  • 15. Pedersen, GP
    et al.
    Fäldt, P
    Bergenståhl, B
    YKI – Ytkemiska institutet.
    Kristensen, HG
    Solid state characterisation of a dry emulsion: a potential drug delivery system1998In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 171, no 2, p. 257-270Article in journal (Refereed)
    Abstract [en]

    Dry emulsions were prepared by spray drying liquid emulsions in a laboratory spray dryer. Lactose alone, and lactose in combination with maltodextrine, was used as a water soluble, solid carrier. Sodium caseinate was used as emulsifying agent and griseofulvin was used as an oil soluble model drug substance in very low concentration. Different fats were applied; soybean oil (liquid), hardened coconut oil (semisolid) and hardened rapeseed oil, being solid at room temperature. The surface of the powder particles was mainly made up of sodium caseinate, while the core was made up of fat dispersed in a carrier matrix of amorphous lactose. Amorphous lactose is very sensitive to moisture, and during moisture uptake recrystallisation of lactose takes place and the physical structure of the powder particle was changed. By addition of maltodextrine as carrier, the physical structure of the spray dried powders was tried to be maintained during recrystallisation of lactose. Reconstitution properties of the spray dried powders were investigated and correlated to solid state characterisation of the powders performed by Scanning Electron Microscope (SEM), Differential Scanning Calorimetry (DSC), X-ray powder diffraction and Electron Spectroscopy for Chemical Analysis (ESCA).

  • 16. Petrov, O
    et al.
    Furó, I
    Schuleit, M
    Domanig, R
    Plunkett, M
    YKI – Ytkemiska institutet.
    Daicic, J
    YKI – Ytkemiska institutet.
    Pore size distributions of biodegradable polymer microparticles in aqueous environments measured by NMR cryoporometry2006In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 309, p. 157-162Article in journal (Refereed)
  • 17. Scherlund, M
    et al.
    Brodin, A
    Malmsten, M
    YKI – Ytkemiska institutet.
    Micellization and gelation in block copolymer systems containing local anesthetics2000In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 211, p. 37-49Article in journal (Refereed)
    Abstract [en]

    A formulation consisting of a eutectic mixture of lidocaine and prilocaine, Lutrol(R) F68 and Lutrol(R) F127, suitable for anesthetizing the periodontal pocket has previously been developed. This consists of discrete micelles with a diameter of 20-30 nm and has a suitable gelation temperature, a good release profile and excellent long-term stability. In this study, the unimer/micelle transition and gel formation of the formulation, in its concentrated state, are investigated using differential scanning calorimetry (DSC), dye solubilization, rheology, and nuclear magnetic resonance (NMR) self-diffusion. The critical micellization temperature (cmt) and gelation temperature are found to be interconnected and influenced by cosolutes, such as electrolytes and hydrophobic substances, the latter as found particularly for the eutectic mixture of the local anesthetic agents lidocaine and prilocaine. Both cmt and the gelation temperature decrease with increasing pH of the system, i.e. at reduced solubility of the active ingredients. Moreover, both cmt and the gelation temperature increase upon diluting the system with water. The ratio between the two block copolymers present in the system also has an impact on both cmt and the gelation temperature, resulting in a decrease in onset tt temperature of both processes with an increase of Lutrol(R) F127, The amount of the active ingredients present in the micelle phase depends on the pH of thc system bring approximately 0% w/w at pH 5, 50-60% w/w at pH 7.8 and 80% w/w at pH 9.

  • 18. Scherlund, M
    et al.
    Malmsten, M
    YKI – Ytkemiska institutet.
    Brodin, A
    Stabilization of a thermosetting emulsion system using ionic and nonionic surfactants1998In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 173, p. 103-116Article in journal (Refereed)
    Abstract [en]

    Ways of achieving a suitable local anesthetic formulation for use in the periodontal cavity were investigated in this study. By choosing poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers as excipients, formulations which are low viscosity fluids at room temperature and rigid elastic gels at body temperature are obtained. Despite the solubilizing capacity of these polymers, formulations containing Lutrol(R) F127 (EO99PO65EO99) and the active ingredients lidocaine and prilocaine at the desired concentrations, i.e. approximately 25 mg g(-1) of each component, are unstable. In order to achieve a more stable formulation a second surfactant can be added to the system since it could help both to solubilize the hydrophobic active ingredients and to stabilize the droplets of lidocaine and prilocaine from flocculation and coalescence. Thus, formulations containing local anesthetic compounds comprising the oil phase, a block copolymer giving the system unique rheological properties, and a suitable second surfactant were evaluated with regard to rheological behavior, drug release properties and stability. The system needs to be balanced regarding the concentration of polymer, active ingredients and surfactant in order to achieve a formulation with suitable properties. Stable formulations with appropriate characteristics for the application in focus here were obtained with anionic, cationic and nonionic surfactants.

  • 19. Scherlund, M
    et al.
    Malmsten, M
    YKI – Ytkemiska institutet.
    Holmqvist, P
    Brodin, A
    Thermosetting microemulsions and mixed micellar solutions as drug delivery systems for periodontal anesthesia2000In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 194, p. 103-116Article in journal (Refereed)
  • 20. Silvander, M
    et al.
    Hellström, A
    Wärnheim, T
    Claesson, P
    YKI – Ytkemiska institutet.
    Rheological properties of phospholipid-stabilized parenteral oil-in-water emulsions - effects of electrolyte concentration and presence of heparin2003In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 252, p. 123-132Article in journal (Refereed)
    Abstract [en]

    The theological properties of the parenteral oil-in-water emulsion Intralipid(TM) were investigated. The viscosity data at different phase volumes correlated well with that obtained via a theoretical model developed by Yaron and Gal-Or. The model also describes the temperature dependence well. The effects of electrolyte addition were also investigated. Monovalent sodium chloride had practically no influence on viscosity. Calcium chloride, on the other hand, had a large impact on viscosity even at low concentrations. It was shown that the obtained maximum in viscosity coincided with the zeta-potential being close to zero. The resulting increase in viscosity is due to flocculation that leads to an increase in apparent phase volume. A similar behaviour was obtained with magnesium chloride with the difference that the maximum in viscosity was shifted to higher electrolyte concentrations. This is interpreted as that because magnesium binds strongly to the hydration water than does calcium. The addition of the negatively charged anti-coagulant heparin causes flocculation in the presence of small amounts of calcium. The amounts of calcium needed for such bridging flocculation is lower than what is needed in order to create a positive potential at the surfaces of the droplets. A fraction of the floes is not broken down even by extensive shear

  • 21. Sjöström, B
    et al.
    Bergenståhl, B
    YKI – Ytkemiska institutet.
    Preparation of submicron drug particles in lecithin-stabililized o/w emulsions I. Model studies of the precipitation of cholesteryl acetate1992In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 84, p. 107-116Article in journal (Refereed)
    Abstract [en]

    Nanoparticles of a model drug, viz. cholesteryl acetate. were prepared. The cholesteryl acetate was dissolved in cyclohexane containing lecithin. The organic solution was emulsified in an aqueous solution containing a cosurfactant. A stable o/w-emulsion resulted. The solvent was evaporated from the emulsion and cholesteryl acetate precipitated in the emulsion droplets. The size of the particles was almost not affected by the cholesteryl acetate concentration in cyclohexane. Furthermore, the increase in particle size, as a result of an increased oil/water ratio was negligible. With a blend of phosphatidylcholine and sodium salt of glycocholic acid as emulsifiers, particle sizes down to 25 nm were obtained, The ratio between phosphatidylcholine and sodiumglycocholate seems to be critical. In increasing the ratio above 9/1, the suspension becomes more instable as is noticed by an increase in particle size during storage. The optimal conditions coincide with those giving an extensively swelling lamellar liquid crystalline phase containing phosphatidylcholine and sodiumglycocholate.

  • 22. Sjöström, B
    et al.
    Westesen, K
    Bergenståhl, B
    YKI – Ytkemiska institutet.
    Preparation of submicron drug particles in lecithin-stabilized o/w emulsions. II. Characterization of cholesteryl acetate particles1993In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 94, p. 89-101Article in journal (Refereed)
    Abstract [en]

    Submicron particles of a model drug, viz., cholesteryl acetate (CA), have been characterized. The particles were prepared by precipitation of CA in the dispersed phase of an o/w emulsion stabilized by two different emulsifier systems i.e., (a) a mixture of lecithin and sodium glycocholate and (b) a polyoxyethylene sorbitan fatty acid ester. The particle size has been determined by photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM). The average particle size, by number, was determined by PCS to be 21-144 nm depending on the emulsifier system used in the particle preparation. The smallest mean particle size of 21 nm was achieved with a blend of lecithin and sodium glycocholate. According to TEM pictures, the particles have a smooth surface and are spherical, and the majority of the particles seem to be amorphous, exhibiting neither microporosity in the particles nor aggregation between the particles. The transition temperature of cholesteryl acetate in the particles prepared with the blend of lecithin and sodium glycocholate has been determined by differential scanning calorimetry (DSC). The DSC measurements indicate that the melting point at 105°C of the cholesteryl acetate particles prepared with lecithin/sodium glycocholate is lower than that of the pure macroscopic cholesteryl acetate crystals which is 116°C. The irreversible transition of cholesteryl acetate at about 80°C was not observed in the particle form of cholesteryl acetate prepared with the emulsifier blend of phosphatidylcholine and sodium glycocholate. The suspensions have also been investigated by small angle X-ray scattering (SAXS). The cyclohexane residue in the resulting suspensions was below 25 ppm according to analysis by gas chromatography.

  • 23.
    Valente, Filippo
    et al.
    University of Padua, Italy.
    Bysell, Helena
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Simoni, Edi
    University of Padua, Italy.
    Boge, Lukas
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Eriksson, Mimmi
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Martini, Alessandro
    University of Padua, Italy.
    Astolfi, Laura
    University of Padua, Italy.
    Evaluation of toxicity of glycerol monooleate nanoparticles on PC12 cell line.2018In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 539, no 1-2, p. 23-30, article id S0378-5173(18)30054-1Article in journal (Refereed)
    Abstract [en]

    An innovative approach to improve drug delivery is the use of glycerol monooleate nanoparticles. Numerous studies describe their high versatility, low toxicity and ability to carry relatively high loads of conjugated compounds including scarcely soluble ones, providing sustained drug release and increasing drug diffusion and half-life. Despite a growing interest in their potential use for therapeutic applications, there are surprisingly few literature data concerning the toxic effects of these nanoparticles at high concentrations in vitro and in vivo, and their effects on cell metabolism. We produced and characterized from a physical-chemical point of view glycerol monooleate nanoparticles and tested them on the PC12 cell line, a rat model of neuronal differentiation. The toxicity of these nanoparticles was evaluated by molecular methods on cell viability, cell cycle, nanoparticle uptake and induction of apoptosis. The results showed that glycerol monooleate nanoparticles up to 100 μg/mL had no toxic effects on PC12 cells, did not induce significant changes in the cell cycle nor cause apoptosis. The nanoparticles entered PC12 cells 8 h after treatment, successfully delivering the conjugate compound inside cells. Overall, glycerol monooleate nanoparticles did not exhibit significant toxicity on PC12 cell line in concentrations up to 100 µg/mL, supporting their therapeutic use as drug delivery systems.

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