The Experts below are selected from a list of 1986 Experts worldwide ranked by ideXlab platform
Gap-shik Chang - One of the best experts on this subject based on the ideXlab platform.
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Rheological Behavior of Viscoelastic Semi-Solid Ointment Base (Vaseline) in Oscillatory Shear Flow Fields
Journal of Korean Pharmaceutical Sciences, 2006Co-Authors: Kiwon Song, Gap-shik ChangAbstract:Using a Rheometries Dynamic Analyzer (RDA II), the dynamic viscoelastic properties of a semi-solid Ointment Base (vaseline) in large amplitude oscillatory shear flow fields were measured over a temperature range of and the linear viscoelastic behavior in small amplitude oscillatory shear flow fields was investigated over a wide range of angular frequencies. In this article, the nonlinear viscoelastic behavior was reported from the experimentally obtained data and the effect of temperature on this behavior was discussed in detail. In addition, the angular frequency and temperature dependencies of a linear viscoelastic behavior were explained. Finally, the applicability of a time-temperature superposition principle originally developed for polymeric materials was examined using a shift factor. Main results obtained from this study can be summarized as follows : (1) At very small strain amplitude region, vaseline shows a linear viscoelastic behavior independent of the imposed deformation magnitudes. Above a critical strain amplitude , however, vaseline exhibits a nonlinear viscoelastic behavior ; indicating that both the storage modulus and dynamic viscosity are sharply decreased with increasing deformation magnitude. (2) In large amplitude oscillatory shear flow fields, an elastic behavior (storage modulus) has a stronger strain amplitude dependence and begins to show a nonlinear behavior at a smaller strain amplitude region than does a viscous behavior (dynamic viscosity). (3) In small amplitude oscillatory shear flow fields, the storage modulus as well as the loss modulus are continuously increased as an increase in angular frequency and an elastic nature is always superior to a viscous behavior over a wide range of angular frequencies. (4) A time-temperature superposition principle can successfully be applicable to vaseline. This finding allows us to estimate the dynamic viscoelastic behavior of vaseline over an extraordinarily extended range (11 decades) of angular frequencies inaccessible from the experimentally measured range (4 decades).
Kiwon Song - One of the best experts on this subject based on the ideXlab platform.
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rheological behavior of semi solid Ointment Base vaseline in steady shear flow fields
Journal of Pharmaceutical Investigation, 2007Co-Authors: Kiwon Song, Yoonjeong Kim, Chiho LeeAbstract:Using a strain-controlled rheometer [Rheometrics Dynamic Analyzer (RDA II)], the steady shear flow properties of a semi-solid Ointment Base (vaseline) have been measured over a wide range of shear rates at temperature range of . In this article, the steady shear flow properties (shear stress, steady shear viscosity and yield stress) were reported from the experimentally obtained data and the effects of shear rate as well as temperature on these properties were discussed in detail. In addition, several inelastic-viscoplastic flow models including a yield stress parameter were employed to make a quantitative evaluation of the steady shear flow behavior, and then the applicability of these models was examined by calculating the various material parameters (yield stress, consistency index and flow behavior index). Main findings obtained from this study can be summarized as follows : (1) At temperature range lower than , vaseline is regarded as a viscoplastic material having a finite magnitude of yield stress and its flow behavior beyond a yield stress shows a shear-thinning (or pseudo-plastic) feature, indicating a decrease in steady shear viscosity as an increase in shear rate. At this temperature range, the flow curve of vaseline has two inflection points and the first inflection point occurring at relatively lower shear rate corresponds to a static yield stress. The static yield stress of vaseline is decreased with increasing temperature and takes place at a lower shear rate, due to a progressive breakdown of three dimensional network structure. (2) At temperature range higher than , vaseline becomes a viscous liquid with no yield stress and its flow character exhibits a Newtonian behavior, demonstrating a constant steady shear viscosity regardless of an increase in shear rate. With increasing temperature, vaseline begins to show a Newtonian behavior at a lower shear rate range, indicating that the microcrystalline structure is completely destroyed due to a synergic effect of high temperature and shear deformation. (3) Over a whole range of temperatures tested, the Herschel-Bulkley, Mizrahi-Berk, and Heinz-Casson models are all applicable and have an almostly equivalent ability to quantitatively describe the steady shear flow behavior of vaseline, whereas the Bingham, Casson,and Vocadlo models do not give a good ability.
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Rheological Behavior of Viscoelastic Semi-Solid Ointment Base (Vaseline) in Oscillatory Shear Flow Fields
Journal of Korean Pharmaceutical Sciences, 2006Co-Authors: Kiwon Song, Gap-shik ChangAbstract:Using a Rheometries Dynamic Analyzer (RDA II), the dynamic viscoelastic properties of a semi-solid Ointment Base (vaseline) in large amplitude oscillatory shear flow fields were measured over a temperature range of and the linear viscoelastic behavior in small amplitude oscillatory shear flow fields was investigated over a wide range of angular frequencies. In this article, the nonlinear viscoelastic behavior was reported from the experimentally obtained data and the effect of temperature on this behavior was discussed in detail. In addition, the angular frequency and temperature dependencies of a linear viscoelastic behavior were explained. Finally, the applicability of a time-temperature superposition principle originally developed for polymeric materials was examined using a shift factor. Main results obtained from this study can be summarized as follows : (1) At very small strain amplitude region, vaseline shows a linear viscoelastic behavior independent of the imposed deformation magnitudes. Above a critical strain amplitude , however, vaseline exhibits a nonlinear viscoelastic behavior ; indicating that both the storage modulus and dynamic viscosity are sharply decreased with increasing deformation magnitude. (2) In large amplitude oscillatory shear flow fields, an elastic behavior (storage modulus) has a stronger strain amplitude dependence and begins to show a nonlinear behavior at a smaller strain amplitude region than does a viscous behavior (dynamic viscosity). (3) In small amplitude oscillatory shear flow fields, the storage modulus as well as the loss modulus are continuously increased as an increase in angular frequency and an elastic nature is always superior to a viscous behavior over a wide range of angular frequencies. (4) A time-temperature superposition principle can successfully be applicable to vaseline. This finding allows us to estimate the dynamic viscoelastic behavior of vaseline over an extraordinarily extended range (11 decades) of angular frequencies inaccessible from the experimentally measured range (4 decades).
Hans Altorfer - One of the best experts on this subject based on the ideXlab platform.
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Radiolysis characterization of cetostearyl alcohol by gas chromatography-mass spectrometry.
Journal of pharmaceutical and biomedical analysis, 2003Co-Authors: Lan Hong, Hans AltorferAbstract:Methods for sample preparation, assay test and impurity test were established. Degrees of cetostearyl alcohol (CSA) radiolyses in pure state, Ointment Base and in chloramphenicol eye Ointment (CAPEO) were determined at doses of 25 and 50 kGy. Radiolyses of CSA occur in all cases. The degrees are directly proportional to the irradiation dose in each case. Forty-two impurities and radiolysis products were identified using gas chromatography-mass spectrometry. The radiolysis products were assigned to be n-alkane, n-aldehyde and 2-methyl-1-alcohol. Accordingly, the degradation pathways of cetosteary alcohol were elucidated. Radiolysis behaviors of CSA in pure state, eye Ointment Base and CAPEO were studied by assay and impurity analyses. The influence of eye Ointment matrixes is modest and chloramphenicol molecule exhibits slight scavenger function for cetostearyl. Both qualitative and quantitative data confirm that the radiolysis products of CSA do not cause safety concerns for human use.
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Characterization of gamma irradiated petrolatum eye Ointment Base by headspace-gas chromatography-mass spectrometry.
Journal of Pharmaceutical and Biomedical Analysis, 2002Co-Authors: Lan Hong, Hans AltorferAbstract:The effects of gamma irradiation on petrolatum eye Ointment Base (EOB) and its ingredients (white petrolatum, liquid paraffin, and wool fat) were studied at different irradiation doses. Forty-one volatile radiolysis products were detected and identified by a combined system of headspace-gas chromatography-mass spectrometry (HS-GC-MS). The characteristics of the radiolysis products and the degradation pathway were discussed in each case, respectively. GC method demonstrates that the component distribution patterns of eye Ointment as well as its individual ingredients have no differences before and after gamma irradiation. The influence of gamma treatment on EOB was quantitatively determined at 15, 25 and 50 kGy. The concentrations of the radiolysis products increase linearly with increasing doses. Both qualitative and quantitative data show that irradiated eye Ointment is safe for human use.
Apt Gunawan Setiyadi - One of the best experts on this subject based on the ideXlab platform.
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Pengaruh Basis Salep Terhadap Sifat Fisik Sediaan Salep Ekstrak Etanolik Bonggol Pisang Ambon (Musa Paradisiaca Var. Sapientum L.) Sebagai Penyembuhan Luka Terbuka Pada Tikus
2017Co-Authors: Yuliana Fatimah, Apt Gunawan SetiyadiAbstract:The content of ambon banana weevil in the form of flavonoids, saponins and tannins play a role in the healing process of open wounds. The purpose of this research is to analyze the effect of variations Base Ointment in the physical properties and healing open wounds. Extraction of ambon banana weevil done soxhletation with 96% ethanol. Banana weevil is presented in the form of an Ointment with four different Bases are water-soluble Base, Base leached, Base absorption, and a hydrocarbon Base. Observation of physical properties of an Ointment include organoleptic, homogeneity, pH, viscosity, adhesion, and dispersive power for 4 weeks. Wound healing power tests using male rats as many as 27 rats were injured her back with a diameter of ± 1.5 cm. The wounds were applied with Ointment tested and wound diameter was measured from the first day until cured. The results showed variations affect the Ointment Base color, viscosity, dispersive power, and adhesion, but has no effect on homogeneity, and pH. Variations Ointment Base also affects the healing of open wounds. Ambon banana weevil Ointment Base and a water-soluble hydrocarbons provides an open wound healing effect more quickly followed by banana weevil ambon Ointment Base absorption and leached.
Masato Shigeyama - One of the best experts on this subject based on the ideXlab platform.
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Preparation of a gel-forming Ointment Base applicable to the recovery stage of bedsore and clinical evaluation of a treatment method with different Ointment Bases suitable to each stage of bedsore
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, 2004Co-Authors: Masato ShigeyamaAbstract:An Ointment Base for better treatment of bedsores was developed to improve the release rate of minocycline hydrochloride (MH) and the water absorption capacity using various types of hydrophobic to hydrophilic Ointment Bases. The effect of purified lanolin (PL) on the release behavior of MH from a hydrophilic Ointment (HO) Base was the primary focus. It was found that the drug release rate from the Ointment Base was modified according to the method of preparation of the Ointment Base and the type of cyclodextrins admixed. The physicochemical properties, such as viscosity, elution volume, and water absorption, of the Ointment Base were also modified by those factors. To develop an Ointment formulation suitable for the recovery stages of bedsores, including the proliferation period of granulation and the formative period of epidermis, the physicochemical properties of Macrogol Ointment containing various hydrophilic polymers, which have gel-forming ability, were tested. A novel Ointment Base suitable for the treatment in the recovery stage of bedsores was developed using hydrophobically modified hydroxypropyl methylcellulose (HM-HPMC). Considerably sustained release of MH (T50 of 170 at a min) was attained with a macrogol Ointment mixed with HM-HPMC and Carbopol formulation ratio of 3:7. We clinically evaluated the effectiveness of bedsore treatment by applying different Ointment Bases to patients with different stages of bedsores.
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Formulation Design of Ointment Base Suitable for Healing of Lesions in Treatment of Bedsores
Chemical & pharmaceutical bulletin, 2001Co-Authors: Masato Shigeyama, Toyoaki Ohgaya, Hirofumi Takeuchi, Tomoaki Hino, Yoshiaki KawashimaAbstract:We intended to develop a desired Ointment Base suitable for treatment of bedsores including the proliferation of granulation and epidermis. The main bedsore bacteria detected in our hospital were S. aureus in gram-positive coccus and P. aeruginosa in gram-negative bacillus. As the macrogol Ointment (MO) was found to have bactericidal effects on these bacteria, MO was adopted as the Base for the objective Ointment. To improve the properties of the Ointment Base such as regulating the humidity of the exudation and controlling the release of antibiotics formulated in the Ointment, co-formulating effects of various additives to MO were evaluated. The sustained release function of the Ointment Base was obtained by adding hydrophilic petrolatum (HP) to MO. However, the resultant Ointment was found to have a poor humidity regulating property. On the other hand, MO containing 5% of hydroxypropyl cellulose (HPC) showed both the humidity regulating and the controlled drug releasing properties. It was considered that HPC particles dispersed in the Ointment could be swelled by absorbing water to form a gel network. The curd tension meter tests for the Ointments prepared with the various polymers showed that the MO-HPC Base, which showed the highest sustained drug releasing property, was found to have the highest hardness. This result means that HPC formulated into the Base forms the most rigid gel structure to resist the erosion of the Ointment and to control the drug release.
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Preparation of a gel-forming Ointment Base applicable to the recovery stage of bedsore and clinical evaluation of a treatment method with different Ointment Bases suitable to each stage of bedsore
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, 2001Co-Authors: Masato Shigeyama, Hirofumi Takeuchi, Toyoaki Oogaya, Tetsuzi Yoneyama, Manabu Futamura, Takatugu Murakawa, Hirotsugu Shibata, Yoshiaki KawashimaAbstract:A novel Ointment Base suitable for the treatment of bedsore at the recovery stage was developed by the use of hydroxypropyl methylcellulose (HM-HPMC) modified on the basis of the hydrophobicity. A considerable sustained release of drug (minocycline hydrochloride) formulated to the Ointment (T50 of 170 min) was attained with a macrogol Ointment (MO) mixed with the HM-HPMC and Carbopol (CP) of the formulating ratio of 3:7. It was also found that a change in the formulating ratio of HM-HPMC and CP lead to a change in the drug release rate. The water absorption property of the Ointment Base, required to absorb on exudative solution in applying to the bedsore treatment, was as high as that of an Ointment Base containing hydroxypropyl cellulose (HPC) and CP reported in our previous paper. We clinically evaluated the effectiveness of the bedsore treatment, in which different Ointment Bases were applied to patients at different stages of the bedsore. A total of 22 cases were divided into two categories for applying to the different treatments. One category comprised of 11 subjects was treated with a povidone-iodine sugargel, which was the conventional method in our hospital, while the other 11 subjects were treated by the use of the newly developed Ointment Bases in consideration for the different stages of the bedsore. In comparison of the clinical results with the healing index, we ascertained that the latter method was significantly more efficacious (p < 0.01-0.05) than the conventional one. The effectiveness was emphasized in treating the intractable bedsore classified into the grades IV and V. Therefore, we confirmed that the newly developed Ointment Base formulation is useful in treating bedsore at each stage.
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Modification of the Physicochemical Properties of Minocycline Hydrochloride Ointment with Cyclodextrines for Optimum Treatment of Bedsore
Chemical & pharmaceutical bulletin, 2000Co-Authors: Masato Shigeyama, Toyoaki Ohgaya, Hirofumi Takeuchi, Yoshiaki Kawashima, Tomoaki HinoAbstract:Modification to find the best physicochemical properties of minocycilne hydrochloride Ointment for optimum treatment of bedsore was investigated by coformulating various types of cyclodextrins (CyD) in the Ointment Base. It was found that the drug release rate from the Ointment Base was modified according to the preparation method of Ointment Base and the type of CyD admixed. The physicochemical properties, such as viscosity, elution volume, water absorption of Ointment bas were also modified by those factors. The mechanism of physicochemical modification with CyD was explanied by the structural change of Ointment Base and the change of surface tension of emulsifying agent solution with the CyD. The stability of Ointment was investigated by confirming the reproducibility of drug release rate after storage at ambient and cooled temperature conditions. In conclusion, a fused mixed Ointment with β-CyD was found to be preferable for treatment of bedstore, because of the improved drug release rate, lowered viscosity and increased elution volunme of the resultant Ointment.
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Mixed Base of Hydrophilic Ointment and Purified Lanolin to Improve the Drug Release Rate and Absorption of Water of Minocycline Hydrochloride Ointment for Treatment of Bedsores.
Chemical & pharmaceutical bulletin, 1999Co-Authors: Masato Shigeyama, Toyoaki Ohgaya, Hirofumi Takeuchi, Yoshiaki Kawashima, Tomoaki HinoAbstract:A desired Ointment Bases for better treatment of bedsores was developed to improve the release rate of minocycline hydrochloride (MH) and the water absorption capacity using various types of hydrophobic to hydrophilic Ointment Base. The influence of purified lanolin (PL) on the release behavior of MH from hydrophilic Ointment (HO) Base was primarily focused on. It was found that the release rate of drug increased with increase in the hydrophilicity of the Base. A linear correlation between the apparent release rate constant of drug from the HO and PL mixed Ointment Base at various combination ratios and the elution of Ointment Base was noted. The HO Ointment Base containing 30% PL had the highest apparent release rate constant of MH. The mixed Ointment Base with the lowest viscosity showed the highest absorption of water and elution of Ointment Base. In conclusion, it was found that HO (70%) and PL (30%) mixed Ointment Base was a promising candidate for better treatment of bedsores.
