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.

Magnetic resonance imaging of the phase separation in mixed preparations of moisturizing cream and steroid ointment after centrifugation.

A mixed preparation consisting of a water-in-oil emulsion-type moisturizing cream and a steroid ointment is frequently prescribed for the treatment of atopic dermatitis. We have investigated the compatibility of moisturizing creams and ointments because there are concerns regarding the physical stability of these mixed preparations. The key technology used in this study was magnetic resonance imaging (MRI). A commercial moisturizing cream and white petrolatum or clobetasone butyrate (CLB) ointment samples were mixed in a weight ratio of 1 : 1. A centrifugation test protocol (20000×g for 3 min) was implemented to accelerate the destabilization processes in the samples. After centrifugation, the mixed preparations separated into three distinct layers (upper, middle, and lower), while no phase separation was observed using moisturizing cream alone. The phase separation was monitored using chemical shift selective images of water and oil and quantitative T2 maps. In addition, MR and near-infrared spectroscopy were employed for component analysis of each phase-separated layer. Collectively, it was confirmed that the lower layer contained water, oils, and organic solvent, while the upper and middle layers were composed solely of oils. Furthermore, this study investigated the distribution of CLB in the phase-separated samples and showed that a heterogeneous distribution existed. From our results, it was confirmed that the mixed preparation became unstable because of the incompatibility of the moisturizing cream and ointment.

Examination of gelling agents to produce acetaminophen jelly.

The current study used 3 types of carrageenan (denoted here as Car)-κ, ι, and λ-to prepare a jelly vehicle for acetaminophen (AAP), and then compared their usefulness as jelly vehicles. The rheological characteristics of each preparation were assessed and then drug elution from the preparation was assessed using dissolution testing. The behavior of each preparation when immersed in water was also examined using magnetic resonance imaging (MRI) in order to better understand the drug elution behaviour of each preparation. Viscoelasticity measurements revealed that 0.75 w/v%-ι-Car and 1.25 w/v%-λ-Car had viscoelasticity values equivalent to that of 0.5 w/v%-κ-Car. Dissolution testing of these 3 preparations indicated that 100% drug elution took 45 min with 0.5 w/v%-κ-Car while it took only 5 min with 0.75 w/v%-ι-Car and 1.25 w/v%-λ-Car. When deuterium oxide was added to κ-Car 0.5%, the MRI images darkened overall starting immediately after addition. The images revealed that the sample and deuterium oxide quickly mixed. In contrast, images revealed that deuterium oxide gradually penetrated κ-Car 1.0%. MRI images had uniform contrast, and deuterium oxide took 6 h or longer to penetrate the samples overall. These findings suggest that water is less apt to penetrate a jelly with an increased car concentration and a denser 3-dimensional network structure. Differences in the structure of car are said to result in better gelling, with κ having the best gelling characteristics, followed by ι and then λ. Thus, this paper discusses the role that vehicle gelling strength plays in the elution of acetaminophen.