Viscous Formulation Research Articles

Investigating Extracellular Vesicles in Viscous Formulations: Interplay of Nanoparticle Tracking and Nanorheology via Interferometric Light Microscopy

While extracellular vesicles (EVs) demonstrate growing potential as innovative cell‐derived nanobiotherapies in diverse medical contexts, their physical properties (size, integrity, transport, etc.) in drug product formulation remain a critical concern poorly addressed so far. Herein, a methodology that relies on nanoparticle tracking analysis by interferometric light microscopy (ILM) for analyzing the concentration and size distribution of nanoparticles as well as their interactions with their local environment through a nanorheological approach is introduced. The analysis of interference patterns enables nanoparticles tracking not only in aqueous solutions but also in complex media with high‐viscosity or non‐Newtonian behavior, particularly pertinent for characterizing EV formulations. A proof of concept for in situ tracking of EVs suspended in Poloxamer‐407 as drug delivery system is presented. The ILM‐based analysis enables to 1) measure the viscosity at the nanoscale for Newtonian and non‐Newtonian fluids via calibration beads; 2) analyze data to determine the size distribution of EVs in non‐Newtonian complex fluid such as poloxamer formulation, and 3) analyze the interactions of EVs with poloxamer‐407. The proposed approach represents a valuable tool to understand the nanorheological behavior of EVs in viscoelastic media in situ as well as a quality control test for EV formulations intended to clinical use.

The Design of Novel 3D-Printed, Moulded, and Oral Viscous Budesonide Formulations for Paediatrics: A Comparative Evaluation of Their Mucoadhesive Properties.

Paediatric eosinophilic oesophagitis (EoE) treatment is challenging due to the limited number of age-appropriate formulations. This study aims to develop and evaluate oral viscous suspensions and solid formulations of budesonide (BUD), focusing on their in vitro mucoadhesive properties, to enhance drug delivery and therapeutic outcomes in paediatric EoE. This study encompasses the development of oral viscous suspensions and orodispersible solid formulations (moulded tablets and 3D-printed dosage forms) containing BUD. The formulations underwent quality control tests as per the European Pharmacopoeia, chemical stability assessments, and an in vitro evaluation of their mucoadhesiveness properties. A validated analytical method enabled accurate BUD quantification and efficient extraction, and all developed formulations demonstrated chemical stability for 30 days, meeting Ph. Eur. quality standards. Three-dimensional printing using SSE successfully produced 1 mg and 0.5 mg BUD printlets, complying with quality tests for conventional tablets. Formulations containing xanthan gum (L2-XG and P1-0.5-XG) exhibited superior mucoadhesive properties. L2-XG showed significantly higher mucoadhesion than L1-MC. Among the solid formulations, P1-0.5-XG demonstrated the highest mucoadhesive properties. This is the first study to develop solid oral dosage forms of BUD at a very low dose, specifically for paediatric use. The results highlight the potential of 3D printing for developing individualised orodispersible BUD formulations with improved bioadhesion for paediatric EoE treatment. The L2-XG formulation and the XG-containing printlets are the most promising formulations in terms of increasing contact time with the oesophageal mucosa, which could translate into improved therapeutic efficacy in this patient population.

On-the-Fly Unsteady Adjoint Aerodynamic and Aeroacoustic Optimization Method

An on-the-fly unsteady adjoint-based aerodynamic and aeroacoustic optimization methodology is presented, aiming to achieve practical engineering applications to explore high-efficiency and low-noise design for aerodynamic shapes. Firstly, a novel on-the-fly hybrid CFD-CAA approach is developed with a close integration of unsteady Reynolds-averaged Navier–Stokes equations and a fully viscous time-domain FW-H formulation. Subsequently, an adjoint-based sensitivity analysis method is proposed for unsteady aerodynamic and aeroacoustic problems with either stationary or moving boundaries, wherein a unified architecture for discrete-adjoint sensitivity analysis of both aerodynamics and aeroacoustics is achieved by integrating the on-the-fly hybrid CFD-CAA approach. The on-the-fly approach facilitates direct evaluation of partial derivatives required for solving adjoint equations, eliminating the need for explicitly preprocessing flow and adjoint variables at all time levels in a standalone adjoint CAA solver and consequently substantially reducing memory consumption. The proposed optimization methodology is implemented within an open-source suite SU2. Results show that the proposed on-the-fly adjoint methodology is capable of achieving highly accurate sensitivity derivatives while significantly reducing memory requirements by an order of magnitude, and further demonstrations of single-objective and coupled aerodynamic and aeroacoustic optimizations highlight the potential of the proposed method in exploring high-efficiency and low-noise design for aerodynamic shapes.

Modification of the Biorelevant Release Testing of Esophageal Applied Mucoadhesive Films and Development of Formulation Strategies to Increase the Mucosal Contact Time.

The increasing prevalence of esophageal disease highlights the clinical relevance of novel, long-lasting mucoadhesive oral dosage forms. The EsoCap device enables targeted local application of films in the esophagus. Biorelevant test systems such as EsoPeriDiss are essential for early formulation development. To this end, the developed and already described release model for simulating the esophagus is being further developed for its potential for biorelevant mapping of the application site through complete tempering and investigation of biorelevant release media. Particularly viscous saliva formulations led to an extension of the retention time. In addition, possible formulation strategies for increasing the retention time of esophageal applied films are being evaluated, such as different film thicknesses, polymer grades and the influence of different active ingredient properties on the retention time. For highly soluble active ingredients, the film thickness represents an option for extending the retention time, while for less soluble substances, the choice of polymer grade may be of particular interest.

Coating powder beds with liquids and foams based on viscous formulations using a twin screw mixer: A continuous process study

Coating with viscous formulations has been essential in numerous industries as it can be a means for providing functionalization, additional properties, as well as other benefits. However, there have been scarce studies that have investigated and proposed methodologies in literature. Continuous coating of powders with viscous liquids poses as a promising technology, which has been mentioned in some studies, but has not yet been thoroughly investigated. This paper employs the use of image processing and analysis, in combination with statistical analysis of particles to evaluate the effectiveness of foams and liquids as a means of coating powder beds. Two different sizes of twin screw mixers that are working in continuous operation are employed, and a new continuous foaming device is fabricated and used for the experiments of coating. The effect of materials and process parameters (as for example rotational speed, and flowrate) on the quality of coating are investigated. Image analysis is used to assess the coating quality. The results clearly showcase the potential of using twin screw mixers for coating purposes and not only for mixing. The hypothesis that using large bubble foams to improve the coating of viscous liquids on particles is proven correct, as they provide higher quality coatings compared to their equivalent liquids, when used in the twin screw mixer. Surprisingly, using a larger scale twin screw mixer, does not show a substantial effect on the mixing, regarding quality, however there is still a requirement for mix optimization for achieving scale-up of this process. These results provide a new pathway for coating powders with viscous formulations in industrial applications, requiring less energy and effort in this process, and can pave the way towards introducing more sustainable industrial methodologies for coating.

Pharmacokinetic Evaluation of Oral Viscous Budesonide in Paediatric Patients with Eosinophilic Oesophagitis in Repaired Oesophageal Atresia.

Eosinophilic oesophagitis is a long-term complication of oesophageal atresia (EA), an uncommon condition that affects approximately 1 in 3500 infants. An exploratory, open-label phase 2 clinical trial was conducted in paediatric eosinophilic oesophagitis after oesophageal atresia (EoE-EA) to assess the safety, pharmacokinetics, and efficacy of oral viscous budesonide (OVB). In total, eight patients were enrolled in the study and assigned to a twice-daily dosing regimen of either 0.8 or 1 mg OVB, depending on age and height, administered for 12 weeks. OVB was safe and effective in the treatment of EoE-EA. The current investigation focuses on the pharmacokinetics of budesonide and the impact of an oral viscous formulation on its absorption and bioavailability. Using a non-linear mixed effects approach, two distinct absorption profiles were identified, despite marked interindividual variability in drug concentrations. Budesonide exposure was higher than previously reported in children following oral inhalation. Even though no significant effect has been observed on serum cortisol levels, future studies should consider exploring different doses, schedules, and/or treatment durations, as there may be an opportunity to reduce the risk of cortisol suppression.

Optimization of Starch-Tannin Adhesives for Solid Wood Gluing.

Bio-based solutions for solid timber gluing have always been a very sensitive topic in wood technology. In this work, we optimize the gluing conditions of a starch-tannin formulation, which allows high performance in dry conditions and resistance to water dipping for 3 h, allowing for the D2 classification to be reached according to EN 204. It was observed that the starch-tannin formulations enhanced their performance by increasing the heating temperature, achieving satisfactory results at 140 °C for 13 min. The proportion of polyphenols in the mixture enhances the water resistance but is only tolerated until 20-30%. In particular, the addition of 10% tannin-hexamine enhances the water-resistant properties of starch for both quebracho and chestnut extract. The application of the jet of cold atmospheric plasma allows for good results with more viscous formulations, increasing their penetration in wood. Solid-state 13C-NMR analysis was also performed, and the spectroscopic information suggests establishing a coordination complex between starch and tannin.

A Novel Ex Vivo Blinking Method for Comparing the Corneal Residence Time of New Shampoo Formulations.

In the cosmetics sector, many products such as shampoos have a probability of accidental ocular exposure during their routine use. One very specific safety parameter is the residence time of the substance on the corneal surface, as prolonged exposure may cause injury. In this study, we developed a system that simulates corneal exposure to blinking and tear flow, for comparing the corneal clearance times of viscous detergent formulations. The Ex Vivo Eye Irritation Test (EVEIT), which uses corneal explants from discarded rabbit eyes from an abattoir, was used as the basis for the new system. To simulate blinking, we developed a silicone wiping membrane to regularly move across the corneal surface, under conditions of constant addition and aspiration of fluid, to mimic tear flow. Six shampoo formulations were tested and were shown to differ widely in their corneal clearance time. Three groups could be identified according to the observed clearance times (fast, intermediate and slow); the reference shampoo had the shortest clearance time of all tested formulations. With this new system, it is now possible to investigate an important physicochemical parameter, i.e. corneal clearance time, for the consideration of ocular safety during the development of novel cosmetic formulations.

Heat transfer analysis of ternary hybrid Williamson nanofluids with gyrotactic microorganisms across stretching surfaces: Local non-similarity method

Managing and controlling energy amidst rapid industrial and technological advancements pose significant challenges. Enhanced heat transfer processes, like free convection in solar panels and nuclear power plants, offer potential to reduce energy consumption and improve system efficiency. Understanding elements such as magnetic fields, thermal radiation, and nanoparticle morphology can optimize fluid dynamics and heat transfer across various domains including energy, aerospace, and nuclear power. This study aims to develop a two-dimensional Williamson fluid model with ternary hybrid nanofluids and gyrotactic microorganisms to deepen our understanding of heat transfer. Methodological enhancements include integrating viscous dissipation formulations and adopting the Rosseland approximation to address radiation effects accurately. By leveraging non-similarity transformations, equations are rendered nondimensional for efficient numerical solutions using MAT LAB. Graphical overviews and tables aid in comprehending key factors for practical applications and engineering analyses.

Sustainable Alternatives to Petroleum-Derived Excipients in Pharmaceutical Oil-in-Water Creams.

Recently, vast efforts towards sustainability have been made in the pharmaceutical industry. In conventional oil-in-water (O/W) cream formulations, various petroleum-based excipients, namely mineral oil and petrolatum, are commonly used. Natural or synthetic excipients, derived from vegetable sources, were explored as alternatives to petroleum-based excipients in prototype topical creams, with 1% (w/w) lidocaine. A conventional cream comprised of petroleum-derived excipients was compared to creams containing sustainable excipients in terms of key quality and performance attributes, physicochemical properties, and formulation performance. The petrolatum-based control formulation had the highest viscosity of 248.0 Pa·s, a melting point of 42.7°C, a low separation index at 25°C of 0.031, and an IVRT flux of 52.9 µg/cm2/h. Formulation SUS-4 was the least viscous formulation at 86.9 Pa·s, hadthe lowest melting point of 33.6°C, the highest separation index of 0.120, and the highest IVRT flux of 139.4 µg/cm2/h. Alternatively, SUS-5 had a higher viscosity of 131.3 Pa·s, a melting point of 43.6°C, a low separation index of 0.046, and the lowest IVRT flux of 25.2 µg/cm2/h. The cumulative drug permeation after 12 h from SUS-4, SUS-5, and the control were 126.2 µg/cm2, 113.8 µg/cm2, and 108.1 µg/cm2, respectively. The composition of the oil-in-water creams had influence on physicochemical properties and drug release; however, skin permeation was not impacted. Sustainable natural or synthetic excipients in topical cream formulations were found to be suitable alternatives to petroleum-based excipients with comparable key quality attributes and performance attributes and should be considered during formulation development.

Solubility of Poorly Soluble Drugs in Phosphatidylcholine-Based Drug Delivery Systems: Comparison of the Loading Capacity in the Bulk Formulation and Its Dispersed State.

The aim of this study was to determine the drug loading capacity of phosphatidylcholine-based formulations for four poorly water-soluble drug substances (clofazimine, fenofibrate, artemether, cannabidiol). Two self-dispersing lipid formulations were investigated, which consisted of soybean phospholipids, medium-chain triglycerides and ethanol with a different phospholipid-oil ratio. The direct loading of the bulk formulation was conducted with dual centrifugation, which proved to be a suitable method for screening experiments with the highly viscous formulations. To estimate possible precipitation after dispersion in the gastrointestinal fluids, the solubility of the drugs was investigated in the dispersed formulations. For this purpose, nanodispersions were prepared from the bulk formulations via high pressure homogenization and subsequently subjected to passive loading. A newly developed HPLC method with Charged Aerosol Detection allowed a simultaneous evaluation of the content of soybean lecithin and medium-chain triglycerides in the nanodispersions. When comparing the two phosphatidylcholine-based formulations, a high content of oil was advantageous with regard to a high loading capacity. Drug substances with melting points below 150 °C exhibited a high solubility in the phospholipid-based formulations. A surprisingly high solubility was observed for artemether and cannabidiol with up to 13.0% and 33.3% drug loaded to the formulations, respectively. In the dispersions, a similar solubility as in the bulk formulations was obtained for fenofibrate and cannabidiol. Clofazimine yielded a higher loading result in the nanodispersions than in the bulk formulation.

PHbot: Self‐Driven Robot for pH Adjustment of Viscous Formulations via Physics‐informed‐ML**

AbstractpH adjustment is crucial for many industrial products, yet this step is typically performed by manual trial‐and‐error. A particularly industrially relevant yet challenging titration is that of adjusting viscous liquid formulations using weak, polyprotic titrants (usually citric acid). Handling of viscous, non‐Newtonian formulations, with such polyprotic acids preferred for their chelation and buffering effects make a robotic solution challenging. We present a self‐driving pH robot integrated with physics‐informed learning; this hybrid physical‐ML model enables automated titration with weak‐strong acid/base pairs. To deal with the high viscosities of these formulations, we developed specific automated mixing and cleaning protocols. We hit the target pH within two to five iterations over 250 distinct formulations in lab‐scale small‐batch (~10 mL and 12 samples) titrations. In the interest of scaling up to match industrial processes, we also demonstrate that our hybrid algorithm works at ~25× scale‐up. The method is general, and we open‐source our algorithm and designs.

Numerical heat transfer of non-similar ternary hybrid nanofluid flow over linearly stretching surface

The primary objective of this research is to construct a 2D mathematical model to understand the heat transfer phenomena in a ternary hybrid nanofluid across a stretched surface. We endorsed viscous dissipation formulations in energy equations and the radiation impacts may also be precisely handled by using Rosseland approximation. Nanoparticles and their effects are also considered including and The equations used in the model are made nondimensional through non-similarity transformation. In addition, the local non-similarity approach is employed to convert non-similar partial differential equations into ordinary differential equations. These equations can subsequently be solved using the bvp4c MATLAB tool. Key factors have been thoroughly mapped out in graphical form for easy comprehension. In a flow regime, increasing nanoparticle concentration, magnetic number, and Eckert number lowers heat transmission and raises the ternary hybrid nanofluid's temperature profile. The effective skin friction coefficient and Nusselt number are tabulated concerning the aforementioned important factors.

Effect of liquid environment on adhesion strength of bioactive glass-based adhesives to bone

Glass Polyalkenoate Cements (GPCs) are composed of ionomeric glass having setting reaction with aqueous poly(acrylic) acid (PAA). The mechanical properties of GPCs are normally affected by various factors such as the concentration of the acid solution, the molar mass of the polyacid, and the powder:liquid ratio. A previous study using fracture testing of double cantilever beam specimens made with a GPC (GPC A) adhered to bovine bone showed that the mode I energy release rate decreased significantly when the specimens were prepared in a flooded liquid environment, simulating a worst-case surgical sternal closure application. The present study used pull-out and butt strength tests to determine the extent to which the adhesion to bovine bone could be improved in wet environments by using a more viscous adhesive (GPC B). The pull-out samples were prepared in both dry and flooded liquid environments and incubated in both humid and flooded liquid environments at 37 °C for two time periods: one and seven days. Overall, the pull-out strength of GPC B was found to be between 56% and 808% higher than GPC A, indicating that the more viscous formulation could mitigate the effects of the wet environment. The GPC B samples prepared and incubated in a flooded liquid environment (L-LI) had a significantly lower pull-out strength than all three other conditions: (1) when prepared in a dry environment and incubated in either a liquid (D-LI) or (2) humid environment (D-H), and (3) when prepared in a liquid environment and incubated in a humid one (L-H), which were all of similar strength. No significant difference in pull-out strength between the samples tested after 1 and 7 days of incubation was found indicating that robust adhesion strength was obtained rapidly. To further assess the adhesive strength for augmenting sternal closure, GPC B and bovine bone were used to create butt joints which were tested at strain rates typical of breathing and coughing. The tests revealed that GPC B's viscoelastic properties resulted in a higher butt joint strength for coughing loads compared to breathing. Overall, the results of the present study show that when the adhesives are expected to be subjected to a flooded liquid environment while they set, significant gains in adhesive strength can be obtained by using more viscous GPC adhesives.

Numerical study of dissipative SW/MWCNT-nanofluid coating flow from a stretching wall to a porous medium with shape factor effects

A mathematical model is developed for incompressible steady-state dissipative CNT-aqueous nanofluid boundary layer flow from a stretching sheet to a saturated isotropic porous medium. Three different CNT shapes (spheres, blades and platelets) are considered. Both single-walled (SWCNT) and multi-walled (MWCNT) carbon nanotubes are examined. A Darcy-Brinkman model is adopted for the porous medium and a modified viscous dissipation formulation is considered which features porous media influence in the energy conservation equation. Appropriate expressions are deployed for the CNT-modified nanofluid viscosity, density, specific heat capacity, thermal conductivity and CNT shape factor. Via similarity transformations, the governing conservation equations for mass, momentum and energy with associated boundary conditions are normalized to generate a coupled nonlinear ordinary differential boundary value problem. A numerical solution is presented with the robust MATLAB-based bvp4c method and 4th order Runge-Kutta shooting scheme. Validation with previous studies is included. Velocity, temperature, skin friction and Nusselt number are computed for a range of selected parameters. The computations show that elevation in CNT volume fraction parameter accelerates the boundary layer flow whereas increment in the Darcian (inverse permeability) parameter induces strong deceleration. MWCNTs produce higher velocities than SWCNTs. Temperature and thermal boundary layer thickness are found to be enhanced with increasing Eckert number, Darcian (inverse permeability) parameter, CNT volume fraction and CNT shape factor. Significantly greater temperatures are computed for MWCNTs.

A new strategy for the reinforcement of paraffin-based fuels based on cellular structures: The armored grain — Ballistic characterization

Slow regression rate of the solid fuel is the main limitation for the use of hybrid rocket engines in high thrust applications. Paraffin-based fuels tackle this limitation thanks to the entrainment mass transfer. In this study, ballistic behaviors of conventional polymeric fuel (ABS) and paraffin-based blends are studied and compared with those of the armored grains. These latter are a new generation of fuels featuring 3D printed cellular structures embedded in the wax-based grain. The ballistic characterization focuses on the evaluation of the regression rate (rf) and its dependence on the oxidizer mass flux. Relative ballistic grading of the formulations is pursued via thickness over time methods and an optical technique for rf determination. The armored grains are reinforced by gyroid structures that are 3D printed using three different polymers (ABS, PLA, and Nylon 6) and two relative densities (10% and 15%). Despite the slow burning behavior of the printing polymers, the embedded reinforcement enhances the rf of the paraffin-based formulations, with percent increases ranging from +48% to +91%. This result could be explained by the uneven and irregular texture of the burning surface promoting turbulence (and therefore, propellant mixing) and convective heat transfer. For both the armored grains and the paraffin-based formulations, blending the pristine paraffin wax with polymeric additives results in more viscous formulations and in a rf reduction. Armored grain combustion performance makes this novel fuel an interesting candidate for high-thrust hybrid rockets.

A review on natural polymer locust bean gum

Locust bean pods were utilized as cattle feed for a very long time but now its seed endosperm powder is utilized as locust bean gum in various industries such as food, cosmetic, pharmaceutical, textile, paint, mining, oil drilling and construction industries for its thickening and stabilizing properties. In pharmaceutical industries, locust bean gum is used in the production of solid monolithic matrix systems, films, beads, micro-particles, nano-particles, inhalable and injectable systems, as well as in viscous liquid and gel formulations. Locust bean gum is used as an additive in food industry due to its thickening and stabilizing property. Its application for bakery purposes results in higher baked product yields; it improves the final texture and adds viscosity in dough. Addition of guar gum in cookies dough improves the machinability of the dough which helps in the better handling of dough with minimum requirement of energy and time.

A New Viscous Budesonide Formulation for the Treatment of Eosinophilic Esophagitis in Children: A Preliminary Experience and Review of the Literature.

Eosinophilic esophagitis (EoE) is a chronic disease, characterized clinically by esophageal disfunction. Topical corticosteroids (tCS), predominantly fluticasone and budesonide, are considered the effective first line treatment, as well as an option of maintenance therapy in EoE. The way that tCS are administered significantly affects their effectiveness. There is still no ready-to-use steroid drug to be applied topically to the esophagus in children-a few experimental viscous slurries (mainly of budesonide) have been shown in trials to be more effective than steroids administered via metered dose inhalers (MDIs) and swallowed. The best examined steroid solvent of all is sucralose, a high-intensity artificial sweetener. Although it has been shown in a critical review that it is non-toxic and safe for all consumers, there are still some concerns among patients about its potential adverse effect on humans. Due to that fact, we developed a new viscous formulation and evaluated its effectiveness in the treatment of children with EoE. In an open, prospective, single-center study, we administered our new formulation of viscous budesonide twice daily for 8 weeks in patients with an active EoE. After treatment, we performed a control gastroscopy with the collection and evaluation of histopathological samples. We have proven our formulation effectiveness at 64%, as far as histological remission is concerned. We have also shown a reduction in the mean endoscopic reference score (EREFS) from 3.1 points at the beginning of the study to 1.6 points at the end of the study. Bearing in mind how important the acceptance of the solvent is for long-time compliance, especially among children, we also decided to assess the taste of the formulation. Therefore, we asked 46 adults and 10 children to swallow a sample of the solvent and fill in a short anonymous questionnaire about its taste, smell, consistency and easiness of swallowing. General acceptance for the proprietary solvent was high, reaching 7.5/10 among adults and 6.5/10 in children. To be able to compare the results of our preliminary experience, we reviewed the studies which evaluated substances that have been used so far as steroid solvents for the treatment of EoE. The overall effectiveness of the oral viscous budesonide (OVB) ranged from 65% to 90%, which is consistent with the results obtained in our study. Unfortunately, the high heterogeneity of the studies did not allow us to draw reliable conclusions.

Hot-lithography 3D printing of biobased epoxy resins

The introduction of Hot Lithography has opened new perspective in the field of additive manufacturing especially with regard to high viscous formulations. The access to elevated temperature in the 3D printing process not only reduce the viscosity of resin but it allows to achieve higher curing kinetics and degree of conversion. Therefore, it is possible to process new type of monomers which are not reactive enough at room temperature towards UV-curing expanding the formulation design and selection to the 3D-printing of a broader range of epoxy-based formulations. With regard to climate change and the limitation of fossil resources, new needs arise for the origin of the materials. In this view, we investigated the use of two bio-based epoxy monomers (furandimethanol diglycidyl ether (FDE) and resorcinol diglycidyl ether (RDE)) in Hot Lithography 3D printing. Moreover, we compared the performance of the bio-based resins with a commercial fossil-based one, the 1,4-cyclohexanedimethanol diglycidyl ether (CDE). The photocuring process was fully characterized by means of real-time NIR/photorheology and photo-DSC analysis. The thermo-mechanical properties of the final thermosets were investigated by DMTA and tensile test. Finally, the 3D printing of complex shapes was carried out to demonstrate the possibility to obtain arbitrary self-standing shapes. • Hot-lithography 3D-printing of bio-based epoxy resin. • Photocuring of Furan-dimethanol diglycidyl ether epoxy resin. • Photocuring of 1,4-cyclohexanedimethanol diglycidyl ether.

Analysis of tear film in cystinosis patients treated with topical viscous cysteamine hydrochloride (Cystadrops®)

PurposeThe aim of this study was to evaluate in vivo the tear film in infantile nephropathic cystinosis patients with corneal crystals treated with topical viscous cysteamine hydrochloride (Cystadrops®).MethodsTen eyes of five patients with nephropathic cystinosis aged from 10 to 35 years were included in this study. The patients were under treatment with viscous cysteamine hydrochloride formulation containing 3.8 mg/mL cysteamine (vCH 0.55%, equivalent to 0.55% CH; Cystadrops®; Recordati rare Diseases, Puteaux, France) to reduce corneal crystal density. Five age and sex matched individuals were randomly selected as control group. Tear osmolarity testing (TearLabTM) was performed to assess the in vivo osmolarity of patients under treatment and compared to control group values. Tear film break-up time (TBUT) and basic tear secretion (Schirmer test) were also assessed.ResultsMean tear osmolarity was 294.8 mOsms/L (±10.4), with a mean absolute difference of 1.85 mOsms/L (±2.13) between the eyes. There was no statistically significant difference between the osmolarity readings of cystinosis and the control group (294.8 ± 10.4 vs 299.4 ± 6.2mOsm/L, respectively; p = 0.39). The mean TBUT was 10.2 ± 0.83 s in the study group versus 10 ± 0.7 s in controls (p = 0.62). The mean Schirmer test score was 9.2 ± 0.83 mm in the patients versus 10.2 ± 0.83 mm in the controls (p = 0.14).ConclusionsThe TearLabTM osmolarity system test showed good reliability and precision in repeated measurements. This is the first report using the TearLab osmolarity system to assess tear film in patients with cystinosis treated with vCH 0.55%. TearLabTM examination showed that the use of vCH 0.55% drops does not determine alterations of the tear film quality.