Non-destructive monitoring of creaming of oil-in-water emulsion-based formulations using magnetic resonance imaging

Determining Phase Separation Dynamics with an Automated Image Processing Algorithm

The problems of extracting products efficiently from reaction workups are often overlooked. Issues such as emulsions and rag layer formation can cause long separation times and slow production, thus resulting in manufacturing inefficiencies. To better understand science within this area and to support process development, an image processing methodology has been developed that can automatically track the interface between liquid-liquid phases and provide a quantitative measure of the separation rate of two immiscible liquids. The algorithm is automated and has been successfully applied to 29 cases. Its robustness has been demonstrated with a variety of different liquid mixtures that exhibit a wide range of separation behavior-making such an algorithm suited to high-throughput experimentation. The information gathered from applying the algorithm shows how issues resulting from poor separations can be detected early in process development.

Developing the Resident Measure of Safety in Care Homes (RMOS): A Delphi and Think Aloud Study

OBJECTIVE

This study aimed to develop a measure of contributory factors to safety incidents in care homes to be completed by residents and/or their unpaid carers.

INTRODUCTION

Care home residents are particularly vulnerable to patient safety incidents, due to higher likelihood of frailty, multimorbidity and cognitive decline. However, despite residents and their carers wanting to be involved in safety initiatives, there are few mechanisms for them to contribute and make meaningful safety improvements to practice.

METHODS

We developed 73 evidence-based items from synthesis and existing measures, which we presented to a panel of stakeholders (residents/carers, health/social care professionals and researchers). We used two online rounds of Delphi to generate consensus (80%) on items important to include in the Resident Measure of Safety in Care Homes (RMOS); a consensus meeting was later held. The draft RMOS developed through the Delphi was presented to participants during 'Think Aloud' interviews using cognitive testing techniques.

RESULTS

The 29-item RMOS was developed. Forty-three participants completed Delphi round 1, and 27 participants completed round 2, 11 participants attended the consensus meeting and 12 'Think Aloud' interviews were conducted. Of the 73 original items, 42 items that did not meet consensus in Delphi round 1 were presented in round 2. After the consensus meeting, it was agreed that 35 items would comprise the RMOS questionnaire and were presented in the 'Think Aloud' interviews. Participants suggested numerous changes to items mostly to improve comprehension and ability to answer.

CONCLUSION

We have a developed an evidence-based RMOS, with good face validity, to assess contributory factors to safety in care homes from a resident/carer perspective. Future work will involve psychometrically testing the items in a pilot and developing a complementary simplified, dementia-friendly version to promote inclusivity.

PATIENT OR PUBLIC INVOLVEMENT

Four patient and public contributors worked with researchers to develop the online questionnaires. Patients (residents) and carers participated on the consensus panel. One member of the research team is an expert by lived experience and was involved in design and analysis decisions. The item list and instructions for the questionnaires were reviewed for face validity, understanding and acceptability by a patient and public involvement group and modified.

A comparison of emulsifiers for the formation of oil-in-water emulsions: stability of the emulsions within 9 h after production and MR signal properties

Objective

To provide a basis for the selection of suitable emulsifiers in oil-in-water emulsions used as tissue analogs for MRI experiments. Three different emulsifiers were investigated with regard to their ability to stabilize tissue-like oil-in-water emulsions. Furthermore, MR signal properties of the emulsifiers themselves and influences on relaxation times and ADC values of the aqueous phase were investigated.

Materials and methods

Polysorbate 60, sodium dodecyl sulfate (SDS) and soy lecithin were used as emulsifiers. MR characteristics of emulsifiers were assessed in aqueous solutions and their function as a stabilizer was examined in oil-in-water emulsions of varying fat content (10, 20, 30, 40, 50%). Stability and homogeneity of the oil-in-water emulsions were evaluated with a delay of 3 h and 9 h after preparation using T₁ mapping and visual control. Signal properties of the emulsifiers were investigated by ¹H-MRS in aqueous emulsifier solutions. Relaxometry and diffusion weighted MRI (DWI) were performed to investigate the effect of various emulsifier concentrations on relaxation times (T₁ and T₂) and ADC values of aqueous solutions.

Results

Emulsions stabilized by polysorbate 60 or soy lecithin were stable and homogeneous across all tested fat fractions. In contrast, emulsions with SDS showed a significantly lower stability and homogeneity. Recorded T₁ maps revealed marked creaming of oil droplets in almost all of the emulsions with SDS. The spectral analysis showed several additional signals for polysorbate and SDS. However, lecithin remained invisible in ¹H-MRS. Relaxometry and DWI revealed different influences of the emulsifiers on water: Polysorbate and SDS showed only minor effects on relaxation times and ADC values of aqueous solutions, whereas lecithin showed a strong decrease in both relaxation times (r_1,lecithin = 0.11 wt.%⁻¹ s⁻¹, r_2,lecithin = 0.57 wt.%⁻¹ s⁻¹) and ADC value (Δ(ADC)_lecithin =  − 0.18 × 10^–3 mm²/s⋅wt.%) with increasing concentration.

Conclusion

Lecithin is suggested as the preferred emulsifier of oil-in-water emulsions in MRI as it shows a high stabilizing ability and remains invisible in MRI experiments. In addition, lecithin is suitable as an alternative means of adjusting relaxation times and ADC values of water.

What does safety in mental healthcare transitions mean for service users and other stakeholder groups: An open-ended questionnaire study

BACKGROUND

Historically, safety mental health research has tended to focus on risks of homicide, suicide and deaths. Although wider safety issues are now recognized in regards to mental health services, the safety of mental health transitions, a key research and policy priority according to World Health Organisation, has not been explored.

OBJECTIVE

The purpose of this study was to investigate perceptions of safety in mental health transitions (hospital to community) amongst five stakeholder groups.

DESIGN AND SETTING

An online, international cross-sectional, open-ended questionnaire.

PARTICIPANTS

There were five stakeholder participant groups: service users; families/carers; mental health-care professionals; researchers; and end users of research.

RESULTS

Ninety-three participants from 12 different countries responded. Three overarching themes emerged: 'individual/clinical', 'systems/services' and 'human, behavioural and social' elements of safe mental health transitions. Whilst there was a great focus on clinical elements from researchers and healthcare professionals, service users and carers considered safety in terms of human, behavioural and social elements of transitional safety (ie loneliness, emotional readiness for discharge) and systems/services (ie inter-professional communication).

DISCUSSION

Safety in mental health-care transitions is perceived differently by service users and families compared to healthcare professionals and researchers. Traditional safety indicators for care transitions such as suicide, self-harm and risk of adverse drug events are raised as important. However, service users and families in particular have a much wider perception of transitions safety.

CONCLUSION

Future quality and safety research and policy should consider including a service user voice and consider integration of psychosocial elements in discharge interventions.

[Examples of Clinical Formulation Design at a University and Response to Clinical Need]

In the healthcare setting, the handling of clinical preparations is essential for the development of tailor-made pharmaceutical agents. However, during the design and development of new clinical formulations, pharmacists may encounter various questions and problems related to handling the formulations, such as a lack of knowledge of and experience in prescription design. In addition, if pharmacists require assistance to solve problems, it is rare to find a person with sufficient knowledge of and experience with the formulation in their facilities, and there are few connections among facilities; therefore, in practice, no consultants are available for advice. Universities may play an important role in solving this problem. We believe that it would be beneficial for both clinical practitioners and universities to develop a plan-do-check-action (PDCA) cycle that brings needs, problems, and questions from clinical sites to universities where research is conducted and the results are fed back to the clinics. This complements one of the major missions of universities as research institutes, which is to compile evidence. For new drug candidates that require a high degree of support from universities, the demonstration of sufficient safety information to warrant clinical trials and subsequent drug development will increase pharmacists' awareness of drugs and lead to uptake of formulations. This paper introduces the case for clinical formulation design in universities as part of the C (check) element of the PDCA cycle and how this corresponds to the needs of the pharmaceutical industry.

Time-temperature superposition principle for the kinetic analysis of destabilization of pharmaceutical emulsions

The time-temperature superposition principle (TTSP) was applied to the destabilization kinetics of a pharmaceutical emulsion. The final goal of this study is to predict precisely the emulsion stability after long-term storage from the short-period accelerated test using TTSP. As the model emulsion, a cream preparation that is clinically used for the treatment of pruritus associated with chronic kidney disease was tested. After storage at high temperatures ranging from 30 to 45 °C for designated periods, the emulsion state was monitored using magnetic resonance imaging, and then the phase separation behaviors observed were analyzed according to the Arrhenius approach applying TTSP. The Arrhenius plot showed a biphasic change around 35 °C, indicating that the separation behaviors of the sample were substantially changed between the lower (30-35 °C) and higher (35-45 °C) temperature ranges. This study also monitored the coalescence behavior using a backscattered light measurement. The experiment verified that the destabilization was initiated by coalescence of oil droplets and then it eventually led to obvious phase separation via creaming. Furthermore, we note the coalescence kinetics agreed well with the phase separation kinetics. Therefore, in the case of the sample emulsion, the coalescence behavior has a dominant influence on the destabilization process. This study offers a profound insight into the destabilization process of pharmaceutical emulsions and demonstrates the promising applicability of TTSP to pharmaceutical research.

MRI Monitoring of the Mixed State of Admixtures Consisting of Moisturizing Cream and Steroid Ointment during the Mixing Process by a Revolution/Rotation-Type Hybrid Mixer

The admixture of a steroid ointment and a moisturizing cream is frequently prescribed to patients suffering from atopic dermatitis. For the mixing operation, a revolution/rotation-type hybrid mixer is widely used in pharmacy. The purpose of this study was to monitor the mixed state of the admixtures during the mixing process of the hybrid mixer. The key technology used in this study was magnetic resonance imaging (MRI). Two different commercial mometasone furoate-containing ointments were used as a test steroid ointment. After layering the moisturizing cream and the steroid ointment in an ointment bottle, the sample was mixed for a predetermined period using the hybrid mixer. According to MRI transverse relaxation time (T₂) mapping for nondestructive monitoring, it was confirmed that the Flumeta^® ointment-containing admixture became homogeneous by mixing for 60 s or more. As for the mometasone furoate ointment 0.1%-containing admixture, the mixed state, after becoming homogeneous, was separated into two layers again by the prolonged mixing process. From the ¹H-NMR spectra of the phase-separated layers, re-separation was caused by removing aqueous components from the bottom of the samples. MRI is a powerful tool for monitoring the mixed state of the admixture during the mixing process. We believe that our findings offer profound insights into the clinical practice of the mixing operation using a hybrid mixer.

Nondestructive Monitoring of the Dispersion State of Titanium Dioxide Nanoparticles in Concentrated Suspensions Using Magnetic Resonance Imaging

The purpose of the present study is to demonstrate the applicability of magnetic resonance imaging, especially T₂ relaxation time mapping, for nondestructive monitoring of the dispersion state of nanoparticles (NPs) in concentrated suspensions. TiO₂ 15-nm-diameter NPs, for use in sunscreen lotion products, were examined as a test NP. First, this study investigated whether T₂ is sensitive to the NP concentration. In experiments with pulsed nuclear magnetic resonance on TiO₂ NP suspensions with different organic solvents (ethanol, acetone, and decamethylcyclopentasiloxane), the T₂ of each solvent varied in the suspensions according to the NP concentration. This study also confirmed that T₂ mapping was effective for visualizing differences in NP concentration. Subsequently, gravitational sedimentation of the test suspensions was investigated. T₂ mapping exhibited better detection sensitivity to sedimentation occurring in concentrated suspensions than visual observation, as it enabled the detection of changes in NP distributions that could not be visible to the naked eye. In addition, measurements of backscattered light enabled the full understanding of the dispersion stability of the TiO₂ NPs in each solvent. Finally, the present study evaluated the centrifuge sedimentation of a commercial TiO₂ NP suspension. T₂ mapping clearly showed the complicated sedimentation behavior induced by the centrifugation treatment. The simulated fluid flow was consistent with the particle distribution in the centrifuged sample; thus, the sedimentation was believed to have developed in accordance with the vorticity generated by the centrifugation.

Stability of Mixed Preparations Consisting of Commercial Moisturizing Creams with an Ointment Base Investigated by Magnetic Resonance Imaging

A moisturizing cream mixed with a steroid ointment is frequently prescribed to patients suffering from atopic dermatitis. However, there is a concern that the mixing operation causes destabilization. The present study was performed to investigate the stability of such preparations closely using magnetic resonance imaging (MRI). As sample preparations, five commercial moisturizing creams that are popular in Japan were mixed with an ointment base, a white petrolatum, at a volume ratio of 1 : 1. The mixed preparations were stored at 60°C to accelerate the destabilization processes. Subsequently, the phase separations induced by the storage test were monitored using MRI. Using advanced MR technologies including spin-spin relaxation time (T₂) mapping and MR spectroscopy, we successfully characterized the phase-separation behavior of the test samples. For most samples, phase separations developed by the bleeding of liquid oil components. From a sample consisting of an oil-in-water-type cream, Urepearl Cream 10%, a distinct phase-separation mode was observed, which was initiated by the aqueous component separating from the bottom part of the sample. The resultant phase separation was the most distinct among the test samples. To investigate the phase separation quantitatively and objectively, we conducted a histogram analysis on the acquired T₂ maps. The water-in-oil type creams were found to be much more stable after mixing with ointment base than those of oil-in-water type creams. This finding strongly supported the validity of the mixing operation traditionally conducted in pharmacies.

Self-organizing Map Analysis for Understanding Comprehensive Relationships between Formulation Variables, State of Water, and the Physical Stability of Pharmaceutical Emulsions

The physical stability of pharmaceutical emulsions is an important quality attribute to be considered. To obtain a better understanding of this issue, this study investigated the contribution of the state of water to the physical stability of pharmaceutical emulsions. The key technology to evaluate the state of water was magnetic resonance imaging (MRI). For sample preparation, model emulsions with different formulation variables (surfactant content, water content, and hydrophilic-lipophilic balance) were prepared. The T1 relaxation time, diffusion coefficient, and viscosity were measured as physical properties. The physical stability of the samples was evaluated using apparent diffusion coefficient maps acquired by MRI. Data analysis of the observed data was performed using the nonlinear response surface method and Kohonen's self-organizing map (SOM). It was determined that, depending on the formulation variables, the state of water was substantially changed and it played a significant role in the physical stability. SOM analysis successfully classified the conditions of formulation variables into four distinct clusters in terms of the similarity of the physical properties of the resultant emulsions, and then clarified the characteristics of the stable emulsions. This study provided us with a comprehensive understanding of the formulation variables, physical properties, and stability concerning the preparation of the model emulsion.

Magnetic resonance imaging study on the physical stability of menthol and diphenhydramine cream for the treatment of chronic kidney disease-associated pruritus

A cream that contains menthol and diphenhydramine is widely prepared in hospital pharmacies and prescribed to patients for the treatment of pruritus associated with chronic kidney disease. However, there is a serious concern regarding its physical stability; therefore, we investigated this issue using magnetic resonance imaging (MRI). For a sample preparation, a menthol-containing ethanol solution was mixed with a commercial diphenhydramine cream. After storage for 7 d at 40°C, substantial phase separation into two distinct layers (upper and lower layers) was observed in the sample. This study further examined the components of the phase-separated layers using magnetic resonance (MR) spectroscopy and chemical shift selective images, and it was verified that the upper layer consisted of packed oil droplet layers, whereas the lower was an aqueous phase. Subsequently, the time-dependent phase separation of the sample at different temperatures was investigated. From the MR images, including a T2 relaxation time map and apparent diffusion coefficient maps, it was obvious that the phase separation developed further with increasing temperature; the most substantial phase separation was observed from the sample stored at 40°C, while no phase separation was detected at 25°C. In the final phase of this study, we conducted a formulation study and succeeded in improving the cream's physical stability by adding a hydrophilic surfactant to the preparation.