| 1. |
- Ali, Abdullah, 1985-, et al.
(författare)
-
Relationship between sensorial and physical characteristics of topical creams : A comparative study on effects of excipients
- 2022
-
Ingår i: International Journal of Pharmaceutics. - : Elsevier B.V.. - 0378-5173 .- 1873-3476. ; 613
-
Tidskriftsartikel (refereegranskat)abstract
- Rising consumer demands for safer, more natural, and sustainable topical products have led to increased interest in finding alternative excipients, while retaining functionality and cosmetic appeal. Particle-stabilized Pickering creams have emerged as possible alternatives to replace traditional surfactant-stabilized creams and are thus one of the focuses in this study. The aim of this paper was to study relationships between sensorial characteristics and physical properties to understand how different excipients affect these aspects, comparing one starch particle–stabilized and three surfactant-stabilized formulations. A human panel was used to evaluate sensorial perception, while physical properties were deduced by rheology and tactile friction, together with in vivo and ex vivo skin hydration measurements. The results show that sensorial attributes related to the application phase can be predicted with rheology, while afterfeel attributes can be predicted with tactile friction studies. Differences in rheological and sensory properties among surfactant-based creams could mainly be attributed to the type of emollients used, presence of thickeners and surfactant composition. Differences between surfactant-based creams and a Pickering cream were more evident in relation to the afterfeel perception. Presence of starch particles in the residual film on skin results in high tactile friction and low perception of residual coating, stickiness, greasiness, and slipperiness in sensorial afterfeel. © 2021 The Authors
|
|
| 2. |
- Ali, Abdullah, 1985-, et al.
(författare)
-
Tactile friction of topical creams and emulsions : Friction measurements on excised skin and VitroSkin® using ForceBoard™
- 2022
-
Ingår i: International Journal of Pharmaceutics. - : Elsevier B.V.. - 0378-5173 .- 1873-3476. ; 615
-
Tidskriftsartikel (refereegranskat)abstract
- Tactile perception can be investigated through ex vivo friction measurements using a so–called ForceBoard™, providing objective assessments and savings in time and money, compared to a subjective human panel. In this work we aim to compare excised skin versus VitroSkin® as model substrates for tactile friction measurements. A further aim is to detect possible differences between traditional surfactant-based creams, and a particle-stabilized (Pickering) cream and investigate how the different substrates affect the results obtained. It was found that the difference in tactile friction between excised skin and VitroSkin® was small on untreated substrates. When topical creams were applied, the same trends were observed for both substrates, although the frictional variation over time relates to the difference in surface structure between the two substrates. The results also confirmed that there is a difference between starch-based Pickering formulations and surfactant-based creams after application, indicating that the latter is greasier than Pickering cream. It was also shown that the tactile friction of Pickering emulsions was consistently high even with high amounts of oil, indicating a non-greasy, and non-sticky formulation. The characteristics of starch-stabilized Pickering formulations make them promising candidates in the development of surfactant-free topical formulations with unique tactile properties. © 2022 The Authors
|
|
| 3. |
- Argatov, Ivan, et al.
(författare)
-
Modeling of composite sorption isotherm for stratum corneum
- 2022
-
Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier. - 0005-2736 .- 1879-2642. ; 1864:7, s. 1-8
-
Tidskriftsartikel (refereegranskat)abstract
- Equilibrium water sorption in stratum corneum (SC) is considered by treating it as a biocomposite with two main phases, namely, corneocytes and lipids. To validate the rule of mixtures for the individual phase sorption isotherms, a new flexible fitting model is introduced by accounting for characteristic features observed in the variations of the thermodynamic correction factors corresponding to the individual sorption isotherms. The comparison of the model fitting performance with that of the five-parameter Park's model shows a remarkably good ability to fit experimental data for different types of sorption isotherms. The effect of the lipids content on the variance of the composite sorption isotherm of stratum corneum is highlighted. The sensitivity analysis reveals that for the typical water content 20-30 wt%, which corresponds to the SC in a stable condition, the sensitivity of the composite sorption isotherm to the variation of the lipids content on dry basis is predominantly positive and sufficiently small. The good agreement observed between the experimental sorption isotherm for SC and the composite isotherm, which is based on the rule of mixtures for the individual phase sorption isotherms, yields a plausible conclusion (hypothesis) that the corneocytes-lipids mechanical interaction during unconstrained swelling of the SC membrane in the in vitro laboratory experiment is negligible.
|
|
| 4. |
- Gidvall, Sanna, et al.
(författare)
-
A novel versatile flow-donor chamber as biorelevant ex-vivo test assessing oral mucoadhesive formulations
- 2021
-
Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 166
-
Tidskriftsartikel (refereegranskat)abstract
- Oral transmucosal drug delivery is a non-invasive administration route for rapid therapeutic onset and greater bioavailability avoiding the first-pass metabolism. Mucoadhesive formulations are advantageous as they may retain the drug at the administration site. Proper equipment to assess mucoadhesive properties and corresponding drug absorption is fundamental for the development of novel drug delivery systems. Here we developed a new flow-through donor chamber for well-established diffusion cells, and we tested the effects on drug and formulation retention in situ of adding mucoadhesive polymers or mesoporous silica particles to a reference formulation. Mesoporous silica particles are of particular interest as they may be used to encapsulate and retain drug molecules. Compared to other ex-vivo methods described in literature for assessing mucoadhesive performance and transmucosal drug delivery, this new donor chamber provides several advantages: i) it reflects physiological conditions better as a realistic saliva flow can be provided over the administration site, ii) it is versatile since it can be mounted on any kind of vertical diffusion cell allowing simultaneous detection of drug retention at the administration site and drug permeation through the tissue, and iii) it enables optical quantification of formulations residence time aided by image processing. This new flow-through donor diffusion cell set-up proved sensitive to differentiate a reference formulation from one where 20 %(w/w) Carbomer was added (to further improve the mucoadhesive properties), with respect to both drug and formulation residence times. We also found that mesoporous silica particles, investigated as particles only and mixed together with the reference formulation, gave very similar drug and formulation retention to what we observed with the mucoadhesive Carbomer. However, after some time (>30 min) it became obvious that the tablet excipients in the reference formulation promote particle retention on the mucosa. This work provides a new simple and versatile biorelevant test for the evaluation of oral mucoadhesive formulations and paves the way for further studies on mesoporous silica particles as valuable excipients for enhancing oral mucoadhesion.
|
|
| 5. |
- Jankovskaja, Skaidre
(författare)
-
Non-invasive monitoring of low molecular weight biomarkers relevant to skin inflammation and cancer
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Development of skin inflammation and cancer in viable epidermis and dermis involve slow molecular weight (LMW) metabolites. We hypothesize that these LMW compounds can be collected on the surface of the skin and used for non-invasive diagnostics of skin disorders. Keeping in mind that substantial transdermal penetrationis achieved only for molecules of < 500 Da, we focused on topical monitoring of LMW biomarkers. In this thesis we investigated non-invasive, topical methods for monitoring LMW biomarkers by relevant in vitro and in vivo experiments. The LMW biomarkers were:- reactive oxygen species (ROS), specifically, hydrogen peroxide, H2O2- amino acids and their derivatives, i.e., tryptophan (Trp), kynurenine (Kyn; a Trpderivative), phenylalanine (Phe), and tyrosine (Tyr; a Phe derivative).Initially, we have carried out in vitro experiments using dermatomed porcine skin and cell cultures. We characterized permeability of the biomarkers through skin and assessed methods of their monitoring. By using Prussian white particles, deposited on porcine skin, we demonstrated that hydrophilic biomarkers, such as H2O2, permeate the skin mainly through hair follicle pathways (Paper I). In paper II, we have showed that the enzymes transforming Trp to the inflammation and cancer biomarker Kyn, are expressed in the basal layer of epidermis. The magnitude of changes of the Trp/Kyn ratio in the cell culture model was assessed. In paper III, we have characterized Trp and Kyn permeability through skin in vitro, concluding that their permeabilities through stratum corneum are comparable. By in vivo experiments outlined in Paper IV, we have demonstrated the feasibility of topical, non-invasive sampling of Trp and Kyn, in relation to other amino acids. Kyn detection was compromised by its low abundance on the skin. In paper V, we performed a proof-of-concept study in vivo and confirmed that non-invasive sampling of Trp and amino acids of similar abundance, such as Phe and Tyr, is more robust. We concluded that Phe/Trp ratio might be equally good biomarker of skin disorders as a predicted Trp/Kyn ratio. Summarizing, the results of this thesis provide basic knowledge for deeper clinical studies of non-invasive, topical sampling of hydrophilic LMW biomarkers of skin inflammation and cancer.
|
|
| 6. |
- Jankovskaja, Skaidre, et al.
(författare)
-
Non-invasive skin sampling of tryptophan/kynurenine ratio in vitro towards a skin cancer biomarker
- 2021
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- The tryptophan to kynurenine ratio (Trp/Kyn) has been proposed as a cancer biomarker. Non-invasive topical sampling of Trp/Kyn can therefore serve as a promising concept for skin cancer diagnostics. By performing in vitro pig skin permeability studies, we conclude that non-invasive topical sampling of Trp and Kyn is feasible. We explore the influence of different experimental conditions, which are relevant for the clinical in vivo setting, such as pH variations, sampling time, and microbial degradation of Trp and Kyn. The permeabilities of Trp and Kyn are overall similar. However, the permeated Trp/Kyn ratio is generally higher than unity due to endogenous Trp, which should be taken into account to obtain a non-biased Trp/Kyn ratio accurately reflecting systemic concentrations. Additionally, prolonged sampling time is associated with bacterial Trp and Kyn degradation and should be considered in a clinical setting. Finally, the experimental results are supported by the four permeation pathways model, predicting that the hydrophilic Trp and Kyn molecules mainly permeate through lipid defects (i.e., the porous pathway). However, the hydrophobic indole ring of Trp is suggested to result in a small but noticeable relative increase of Trp diffusion via pathways across the SC lipid lamellae, while the shunt pathway is proposed to slightly favor permeation of Kyn relative to Trp.
|
|
| 7. |
- Jankovskaja, Skaidre, et al.
(författare)
-
Non-Invasive, Topical Sampling of Potential, Low-Molecular Weight, Skin Cancer Biomarkers : A Study on Healthy Volunteers
- 2022
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 94:15, s. 5856-5865
-
Tidskriftsartikel (refereegranskat)abstract
- Monitoring of low-molecular weight cancer biomarkers, suchas tryptophan (Trp) and its derivative kynurenine (Kyn), might beadvantageous to non-invasive skin cancer detection. Thus, we assessedseveral approaches of topical sampling of Trp and Kyn, in relation tophenylalanine (Phe) and tyrosine (Tyr), on the volar forearm of six healthyvolunteers. The sampling was performed with three hydrogels (made ofagarose or/and chitosan), hydrated starchfilms, cotton swabs, and tapestripping. The biomarkers were successfully sampled by all approaches, butthe amount of collected Kyn was low, 20 +/- 10 pmol/cm2.Kynquantification was below LOQ, and thus, it was detected only in 20% oftopical samples. To mitigate variability problems of absolute amounts ofsampled amino acids, Tyr/Trp, Phe/Trp, and Phe/Tyr ratios were assessed,proving reduced inter-individual variation from 79 to 45% and intra-individual variation from 42 to 21%. Strong positive correlation was foundbetween Phe and Trp, pointing to the Phe/Trp ratio (being in the 1.0-2.0 range, at 95% confidence) being least dependent onsampling materials, approaches, and sweating. This study leads to conclusion that due to the difficulty in quantifying less abundantKyn, and thus the Trp/Kyn ratio, the Phe/Trp ratio might be a possible, alternative biomarker for detecting skin cancers.
|
|
| 8. |
- Jankovskaja, Skaidre, et al.
(författare)
-
Visualisation of H2O2 penetration through skin indicates importance to develop pathway-specific epidermal sensing
- 2020
-
Ingår i: Microchimica Acta. - : Springer. - 0026-3672 .- 1436-5073. ; 187:12
-
Tidskriftsartikel (refereegranskat)abstract
- Elevated amounts of reactive oxygen species (ROS) including hydrogen peroxide (H2O2) are observed in the epidermis in different skin disorders. Thus, epidermal sensing of H2O2 should be useful to monitor the progression of skin pathologies. We have evaluated epidermal sensing of H2O2 in vitro, by visualising H2O2 permeation through the skin. Skin membranes were mounted in Franz cells, and a suspension of Prussian white microparticles was deposited on the stratum corneum face of the skin. Upon H2O2 permeation, Prussian white was oxidised to Prussian blue, resulting in a pattern of blue dots. Comparison of skin surface images with the dot patterns revealed that about 74% of the blue dots were associated with hair shafts. The degree of the Prussian white to Prussian blue conversion strongly correlated with the reciprocal resistance of the skin membranes. Together, the results demonstrate that hair follicles are the major pathways of H2O2 transdermal penetration. The study recommends that the development of H2O2 monitoring on skin should aim for pathway-specific epidermal sensing, allowing micrometre resolution to detect and quantify this ROS biomarker at hair follicles. Graphical abstract
|
|
| 9. |
- Kumlien, Christine, et al.
(författare)
-
Research priorities to prevent and treat diabetic foot ulcers-A digital James Lind Alliance Priority Setting Partnership
- 2022
-
Ingår i: Diabetic Medicine. - : John Wiley & Sons. - 0742-3071 .- 1464-5491. ; 39:11
-
Tidskriftsartikel (refereegranskat)abstract
- Aim To establish outcomes of a priority setting partnership between participants with diabetes mellitus and clinicians to identify the top 10 research priorities for preventing and treating diabetic foot ulcers (DFUs). Methods Due to the COVID-19 pandemic, the James Lind Alliance Priority Setting Partnership process was adapted into a digital format which involved a pilot survey to identify understandable uncertainties with high relevance for participants tested by calculating the content validity index; a main survey answered by 53 participants living with diabetes and 49 clinicians; and a final digital workshop to process and prioritise the final top 10 research priorities. Results The content validity index was satisfactory for 20 out of 25 uncertainties followed by minor changes and one additional uncertainty. After we processed the 26 uncertainties from the main survey and seven current guidelines, a list of 28 research uncertainties remained for review and discussion in the digital workshop. The final top 10 research priorities included the organisation of diabetes care; screening of diabetes, impaired blood circulation, neuropathy, and skin properties; vascular surgical treatment; importance of self-care; help from significant others; pressure relief; and prevention of infection. Conclusion The top 10 research priorities for preventing and treating DFUs represent consensus areas from persons living with diabetes and clinicians to guide future research. These research priorities can justify and inform strategic allocation of research funding. The digitalisation of James Lind Alliance methodology was feasible.
|
|
| 10. |
- Lind, Tania K., et al.
(författare)
-
Effects of ethylene oxide chain length on crystallization of polysorbate 80 and its related compounds
- 2021
-
Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 592, s. 468-484
-
Tidskriftsartikel (refereegranskat)abstract
- As a result of the synthesis protocol polyoxyethylene sorbitan monooleate (polysorbate 80, PS80) is a highly complex mixture of compounds. PS80 was therefore separated into its main constituents, e.g. polyoxyethylene isosorbide esters and polyoxyethylene esters, as well as mono- di- and polyesters using preparative high-performance liquid chromatography. In this comprehensive study the individual components and their ethoxylation level were verified by matrix assisted laser desorption/ionization time-of-flight and their thermotropic behavior was analyzed using differential scanning calorimetry and X-ray diffraction. A distinct correlation was found between the average length of the ethylene oxide (EO) chains in the headgroup and the individual compounds' ability to crystallize. Importantly, a critical number of EO units required for crystallization of the headgroup was determined (6 EO units per chain or 24 per molecule). The investigation also revealed that the hydrocarbon tails only crystallize for polyoxyethylene sorbitan esters if saturated. PS80 is synthesized by reacting with approximately 20 mol of EO per mole of sorbitol, however, the number of EO units in the sorbitan ester in commercial PS80 products is higher than the expected 20 (5 EO units per chain). The complex behavior of all tested compounds revealed that if the amount of several of the linear by-products is reduced, the number of EO units in the chains will stay below the critical number and the product will not be able to crystallize by the EO chains.
|
|
