In vitro oral simulation evaluation of palatability and chewability of chewable tablets / 中国药房

OBJECTIVE To evaluate the palatability and chewability of chewable tablets， and provide reference for the quality evaluation of various types of chewable tablets. METHODS Using self-made Glucosamine hydrochloride chewable tablets as the model drug， the quality test was conducted. The in vitro simulation system for chewable tablets was established by using a texture analyzer and rheometer， and an oral simulation experiment was conducted on chewable tablets. The texture analyzer was used to measure the force required for chewing and simulate the static disintegration process of chewable tablets； the rheometer was adopted to measure the viscoelasticity， thixotropy， and deformability of chewable tablets during the chewing process. RESULTS The disintegration time limit， principal component content， and dissolution of self-made Glucosamine hydrochloride chewable tablets all met the limit requirements. The in vitro simulation results of the texture analyzer showed that self-made chewable tablets were easy to chew in both axial and radial directions， and the force required for chewing was within the range of the chewing force of the teeth； chewable tablets could disintegrate at an appropriate time without being chewed and only taken in the oral cavity. The in vitro simulation results of the rheometer showed that the chewable tablets in the oral cavity exhibited a behavior of elasticity as the main factor and viscosity as the secondary factor through the continuous stirring of the tongue， and the viscosity of the chewable tablets gradually decreased with tongue stirring or tooth chewing； when chewing with teeth， the internal force of the chewing tablets decreased， causing plastic deformation and crushing. After being crushed， the shape couldn’t be restored， making it easy to chew and swallow. CONCLUSIONS The combination of texture analyzer and rheometer can be used to simulate the oral chewing process and evaluate the palatability and chewability of self-made Glucosamine hydrochloride chewable tablets. This model can provide reference for the evaluation of various chewable tablets.

Research on batch-to-batch quality control of compound Danshen extract based on physical characterization and multivariate statistical analysis / 中国中药杂志

Physical attributes of Chinese herbal extracts are determined by their chemical components, and the physical and chemical attributes jointly affect the preparation process performance and the final product quality. Therefore, in order to improve the quality control of Chinese herbal extracts, we should comprehensively study the batch-to-batch consistency of physical and chemical attributes as well as the correlations between them. This paper first explored the physical attributes affecting the preparation process performance of the compound Danshen extract and developed a method for characterizing the texture attributes. With such main chemical components as water, phenolic acids, saponins, and saccharides and texture, rheology, and other physical attributes taken into consideration, the batch-to-batch quality fluctuation of products from different production lines and time was analyzed by principal components analysis(PCA). Finally, the correlation and partial least squares(PLS) analysis was conducted, and the regression equation was established. The fitting result of the PLS model for dynamic viscosity was satisfying(R~2Y=0.857, Q~2=0.793), suggesting that the chemical components could be adjusted by the component transfer rate in the extraction process, the impurity removal rate in the alcohol precipitation process, and the water retention rate of the concentration process to meet the control of the extract dynamic viscosity. This study clarified the correlations between physical and chemical attributes of the compound Danshen extract and established a method for controlling its physical attributes based on process regulation, which would provide reference for improving the quality control of Chinese herbal extracts.

Determination of the K-value of different types of povidone by microfluidic rheometry and the relationship between K-value and weight-average molecular weight / 药学学报

italic>K-values of 56 batches of 7 types of povidone were measured by microfluidic rheometry and with a Ubbelohde capillary viscometer. The K-values of the two methods were tested by SPSS software and the results showed that there was no significant difference between the two methods (P > 0.05). Taking K-values measured with the Ubbelohde capillary viscometer (Ku) as the abscissa and K-values measured by microfluidic rheometry (Km) as the ordinate a linear equation was calculated: Km = 0.893 9Ku + 4.617 6, R2 = 0.986 2, with good linearity, indicating that the microfluidic rheometer method can replace the Ubbelohde capillary viscometer in determining K-values of povidone. The microfluidic rheometer method has the benefits of less sample consumption, faster determination, and is more accurate, and it can be used with high-throughput automatic acquisition, which provides a more convenient method for the determination of K-values of different types of povidone. The weight-average molecular weights (Mw) of each type of povidone were measured by gel permeation chromatography-multi angle laser light scattering (GPC-MALLS), and the relationship between Mw and Km was lgMw = -0.000 4 Km2 + 0.072 7 Km + 2.791, R2 = 0.990 1. The fitting relationship was good, and Mw could be calculated by Km by the equation.

Effect of wet mass on dextromethorphan hydrobromide matrix pellets

Dextromethorphan hydrobromide (DM) sustained release matrix pellets containing 10% w/w drug were prepared by an extrusion/spheronization technique. The effect of mixing different concentrations of ethyl cellulose (EC), hydroxypropyl methylcellulpse (HPMC K10), and Carbopol 934 with Avicel PH101 on the rheological properties of pellet wet mass was evaluated using mixer torque rheometry (MTR). The prepared pellets were characterized for size, drug content, and in-vitro DM release rate. The results showed that increasing the concentration of the hydrophobic polymer (EC) with Avicel PH101 decreased wet mass consistency, represented by mass mean line torque. Lower binder ratio was required for optimum wet massing, while mixing with swellable polymers (HPMC and Carbopol) caused a noticeable increase in both mean line torque and binder ratio. Combinations of HPMC and Carbopol at higher concentrations resulted in controlled in vitro release of DM from the prepared pellets. Furthermore, mathematical treatment of the in vitro release data of DM from the prepared pellets showed that all formulations except those containing 5% Carbopol plus 5% HPMC (F10) follow first order release. n values of these formulation were in the range of 0.09-0.40, which support an anomalous non-Fickian release.

Wetting agent dosage screening for traditional Chinese medicine pellet based on torque rheological property / 中国中药杂志

With lubricant and bonding effect simultaneously, wetting agent has direct effect on properties of wet mass and extrudate, thus affecting the forming quality of pellets in extrusion-spheronization process. In this research, 25 representative kinds of traditional Chinese medicine(TCM) were selected as model drugs and 20%, 30% and 40% drug loading were set with MCC as their balling agent. The torque rheological curves were measured to get parameters such as maximum torque (Tmax) and corresponding water addition (WTmax) for these 75 raw materials by a mixer torque rheometer (MTR).The results showed that among 75 representative raw materials, 74 ones could be obtained for spherical pellets under the water addition of WTmax-2. corresponding to the second largest torque in torque rheological curve, suggesting that MTR could be used to select the optimal wetting agent dosage of TCM pellets. So the tedious and expensive pre-production work could be considerably reduced when TCM pellets were prepared.

Research in rheological properties of four types of ophthalmic preparations / 药学学报

This study is prepared to provide the basis of rheological parameters for the additional quality standard of ophthalmic gels, the rheological properties of the ophthalmic gels and the other three types of ophthalmic preparations. The medicines were compared through the study of the rheological properties for four types of ophthalmic preparations. The cone-plate rheometer was used to determine the dynamic and steady rheological parameters of four types of ophthalmic preparations. The similarities and differences of the measured results were analyzed to summarize the rheological indexes and parameters which are applied to distinguish the ophthalmic gels and the other types of ophthalmic preparations. ① The elastic modulus should be greater than the viscous modulus for the ophthalmic gels in the range of the linear viscoelastic region. ② The ophthalmic gels should be shear thinning non-Newtonian fluid with a certain yield stress and thixotropy. ③ The dynamic viscosity of the ophthalmic gels should be greater than 0.5 Pa·S at the temperature of 25℃ with the 50 s-1 shear rate. The typical rheological indexes and parameters of the ophthalmic gels were proposed in this article. The determination methods are simple and feasible. The rheological indexes and parameters have an important significance in the prescription design, production technology and quality control of the ophthalmic gels.

Determination method of dynamic viscosity of methylcellulose / 中国药学杂志

OBJECTIVE: To solve the existing problems of the determination method of dynamic viscosity of methylcellulose in Chinese Pharmacopoeia (2010 edition): METHODS: By virtue of concentric cylinder rheometer, the experiment probes into the influence of shear rate, temperature measurement, the yield value, thixotropic, etc. on the rheological properties of samples, and identifies then the optimum temperature and shear rate of the samples. RESULTS: The optimum conditions were established as temperature of (20±0.1)°C and shear rate of 80 s-1. CONCLUSION: This method is simple and accurate with good repeatability. It can be applied to determine the viscosity of methylcellulose.

Influences of Hot Water Bathing on Whole-blood Fluidity Measured by Falling Needle Rheometer / 日本温泉気候物理医学会雑誌

 We examined changes in the apparent whole-blood viscosity (aWBV) of healthy subjects using non-anticoagulated specimens during Japanese style bathing. We have developed a falling needle rhemeter (FNR) that is able to measure several terminal velocities with resin needles in various densities within 210 s. When a needle falls into whole blood in the columnar container, the parameters of aWBV, shear stress and shear rate can be calculated using the blood density, needle density and terminal velocity of the needle as measured by the FNR. Multiple measurements can be made in one whole-blood fluidity analysis, using only a small amount of specimen without any anticoagulant. In this study, several non-eldery healthy adults remained immersed up to the armpits in a sitting posture in the bathtub. In order to maintain a constant bath temperature, heated tap water kept being added. Whole-blood fluidity was analyzed with several aWBVs at various shear rates measured using the FNR. Referring to a previous study reporting on conditions of hemodynamic change, our preliminary examination found that observation of a change in blood fluidity required 10 min of bathing in water at 42 degrees Celsius. Eight healthy men and one healthy woman therefore took a single-bath for 10 min at 42 degrees Celsius for the single-bathing examination. Six of these nine subjects, including the female subject, showed increased aWBVs in the high-shear-rate region with a single bath. And one subject showed increased aWBVs in the high-shear-rate region, 10 min after bathing. These subjects showed altered whole-blood fluidity in the low-shear-rate region at the time of changing aWBVs in the high-shear-rate region. Six healthy men were enrolled in a double-bathing examination, first bathing for 10 min, then taking a break for 5 min and taking a second bath for 5 min. All subjects showed increased aWBVs in the high-shear-rate region: two of the six enrolled subjects showed increases after the first bath; three subjects showed increases after the second bath; and the remaining subject showed an increase at 10 min after the second bath. All subjects showed increased aWBVs in the high-shear-rate region, and a simultaneous change in whole-blood fluidity in the low-shear-rate region. Notably, the time needed for a change in whole-blood fluidity was very short. To implement the present study, non-elderly adult volunteers were enrolled to reduce the risk of accidents and some limitations were placed on bathing conditions. As changes in blood fluidity were observed under bathing conditions with water temperature over 42 degrees Celsius and immersion up to the armpits in a sitting posture, we concluded that prolonged Japanese-style bathing in water exceeding 42 degrees Celsius is dangerous.

Influences of Hot Water Bathing on Whole-blood Fluidity Measured by Falling Needle Rheometer / 日本温泉気候物理医学会雑誌

 We examined changes in the apparent whole-blood viscosity (aWBV) of healthy subjects using non-anticoagulated specimens during Japanese style bathing. We have developed a falling needle rhemeter (FNR) that is able to measure several terminal velocities with resin needles in various densities within 210 s. When a needle falls into whole blood in the columnar container, the parameters of aWBV, shear stress and shear rate can be calculated using the blood density, needle density and terminal velocity of the needle as measured by the FNR. Multiple measurements can be made in one whole-blood fluidity analysis, using only a small amount of specimen without any anticoagulant. In this study, several non-eldery healthy adults remained immersed up to the armpits in a sitting posture in the bathtub. In order to maintain a constant bath temperature, heated tap water kept being added. Whole-blood fluidity was analyzed with several aWBVs at various shear rates measured using the FNR. Referring to a previous study reporting on conditions of hemodynamic change, our preliminary examination found that observation of a change in blood fluidity required 10 min of bathing in water at 42 degrees Celsius. Eight healthy men and one healthy woman therefore took a single-bath for 10 min at 42 degrees Celsius for the single-bathing examination. Six of these nine subjects, including the female subject, showed increased aWBVs in the high-shear-rate region with a single bath. And one subject showed increased aWBVs in the high-shear-rate region, 10 min after bathing. These subjects showed altered whole-blood fluidity in the low-shear-rate region at the time of changing aWBVs in the high-shear-rate region. Six healthy men were enrolled in a double-bathing examination, first bathing for 10 min, then taking a break for 5 min and taking a second bath for 5 min. All subjects showed increased aWBVs in the high-shear-rate region: two of the six enrolled subjects showed increases after the first bath; three subjects showed increases after the second bath; and the remaining subject showed an increase at 10 min after the second bath. All subjects showed increased aWBVs in the high-shear-rate region, and a simultaneous change in whole-blood fluidity in the low-shear-rate region. Notably, the time needed for a change in whole-blood fluidity was very short. To implement the present study, non-elderly adult volunteers were enrolled to reduce the risk of accidents and some limitations were placed on bathing conditions. As changes in blood fluidity were observed under bathing conditions with water temperature over 42 degrees Celsius and immersion up to the armpits in a sitting posture, we concluded that prolonged Japanese-style bathing in water exceeding 42 degrees Celsius is dangerous.

Rheological characterization of thermoplasticized injectable gutta percha and resilon / 대한치과보존학회지

OBJECTIVES: The purpose of this study was to observe the change in the viscoelastic properties of thermoplasticized injectable root canal filling materials as a function of temperature and to compare the handling characteristics of these materials. MATERIALS AND METHODS: Three commercial gutta perchas and Resilon (Pentron Clinical Technologies) in a pellet form were heated in the Obtura-II system (Obtura Spartan) at 140degrees C and 200degrees C, and the extrusion temperature of the thermoplasticized materials was measured. The viscoelastic properties of the materials as a function of temperature were evaluated using a rheometer. The elastic modulus G', viscous modulus G", loss tangent tandelta, and complex viscosity eta* were determined. The phase transition temperature was determined by both the rheometer and a differential scanning calorimeter (DSC). The consistency of the materials was compared under compacting pressure at 60degrees C and 40degrees C by a squeeze test. RESULTS: The three gutta perchas had dissimilar profiles in viscoelastic properties with varying temperature. The phase transition of softened materials into solidification occurred at 40degrees C to 50degrees C, and the onset temperatures obtained by a rheometer and a DSC were similar to each other. The onset temperature of phase transition and the consistency upon compaction pressure were different among the materials (p < 0.05). Resilon had a rheologically similar pattern to the gutta perchas, and was featured between high and low-flow gutta perchas. CONCLUSIONS: The rheological characteristics of the thermoplasticized root canal filling materials changed under a cooling process. The dissimilar viscoelastic properties among the materials require different handling characteristics during an injecting and compacting procedure.

The change of the initial dynamic visco-elastic modulus of composite resins during light polymerization / 대한치과보존학회지

The aim of this study was to measure the initial dynamic modulus changes of light cured composites using a custom made rheometer. The custom made rheometer consisted of 3 parts: (1) a measurement unit of parallel plates made of glass rods, (2) an oscillating shear strain generator with a DC motor and a crank mechanism, (3) a stress measurement device using an electromagnetic torque sensor. This instrument could measure a maximum torque of 2Ncm, and the switch of the light-curing unit was synchronized with the rheometer. Six commercial composite resins [Z-100 (Z1), Z-250 (Z2), Z-350 (Z3), DenFil (DF), Tetric Ceram (TC), and Clearfil AP-X (CF)] were investigated. A dynamic oscillating shear test was undertaken with the rheometer. A certain volume (14.2 mm3) of composite was loaded between the parallel plates, which were made of glass rods (3 mm in diameter). An oscillating shear strain with a frequency of 6 Hz and amplitude of 0.00579 rad was applied to the specimen and the resultant stress was measured. Data acquisition started simultaneously with light curing, and the changes in visco-elasticity of composites were recorded for 10 seconds. The measurements were repeated 5 times for each composite at 25+/-0.5degrees C. Complex shear modulus G*, storage shear modulus G', loss shear modulus G" were calculated from the measured strain-stress curves. Time to reach the complex modulus G* of 10 MPa was determined. The G* and time to reach the G* of 10 MPa of composites were analyzed with One-way ANOVA and Tukey's test (alpha = 0.05). The results were as follows. 1. The custom made rheometer in this study reliably measured the initial visco-elastic modulus changes of composites during 10 seconds of light curing. 2. In all composites, the development of complex shear modulus G* had a latent period for 1~2 seconds immediately after the start of light curing, and then increased rapidly during 10 seconds. 3. In all composites, the storage shear modulus G' increased steeper than the loss shear modulus G" during 10 seconds of light curing. 4. The complex shear modulus of Z1 was the highest, followed by CF, Z2, Z3, TC and DF the lowest. 5. Z1 was the fastest and DF was the slowest in the time to reach the complex shear modulus of 10 MPa.

A study on the adhesion of a soft liner containing 4-META to the base metal alloy and its viscoelastic property / 대한치과보철학회지

STATEMENT OF PROBLEM: Soft lining materials, also referred to as tissue conditioning materials, tissue treating materials, relining materials, soft liners or tissue conditioners, were first introduced to dentistry by a plastic manufacturer in 1959. Since the introduction of the materials to the dental field, their material properties have been continually improved through the effort of many researchers. Soft lining materials have become widely accepted, particularly by prosthodontists, because of their numerous clinical advantages and ease of manipulation. Unfortunately, few reports have been issued upon the topic of increasing the bond strength between the base metal alloy used in cast denture bases and PMMA soft liner modified with 4-META, nor upon the pattern of debonding and material change in wet environment like a intra oral situation. PURPOSE: The purposes of this study were comparing the bond strength between base metal alloy used for the cast denture bases and PMMA soft liner modified with 4-META, and describing the pattern of debonding and material property change in wet environment like the intraoral situation. MATERIAL AND METHODS: This study consisted of four experiments: 1. The in vitro measurement of shear bond strength of the adhesive soft liner. 2. The in vitro measurement of shear bond strength of the adhesive soft liner after 2 weeks of aging. 3. A comparison of debonding patterns. 4. An evaluation the gelation time of modified soft liner. The soft liner used in this study was commercially available as Coe-soft (GC America.IL., USA), which is provided in forms of powder and liquid. This is a PMMA soft liner commonly used in dental clinics. The metal primer used in this study was 4-META containing primer packed in Meta fast denture base resin (Sun Medical Co., Osaka, Japan). The specimens were formed in a single lap joint design, which is useful for evaluating the apparent shear bond strength of adhesively bonded metal plate by tensile loading. Using the 20x20mm transparent grid, percent area of adhesive soft liner remaining on the shear area was calculated to classify the debonding patterns. To evaluate the change of the initial flow of the modified adhesive soft liner, the gelation time was measured with an oscillating rheometer (Haake RS150W/TC50, Haake Co., Germany). It was a stress control and parallel plate type with the diameter of 35mm. CONCLUSION. Within the conditions and limitations of this study, the following conclusions were drawn as follows. 1. There was significant increase of bond strength in the 5% 4-META, 10% 4-META containing groups and in the primer coated groups versus the control group(P<0.05). 2. After 2 weeks of aging, no significant increase in bond strength was found except for the group containing 10% 4-META (P<0.05). 3. The gelation times of the modified soft liner were 9.3 minutes for the 5% 4-META containing liner and 11.5 minutes for the 10% 4-META liner. 4. The debonding patterns of the 4-META containing group after 2 weeks of aging were similar to those of immediaely after preparation, but the debonding pattern of the primer group showed more adhesive failure after 2 weeks of aging.

Improvement on Quota-sampling Needle & Electric Circuit for MVIS Blood Rheometer / 医疗卫生装备

Objective To improve quota-sampling precision and reproducibility of the impedance blood rheometer. Methods Quota-sampling control circuit and the sampling needle's structure were improved for the early MVIS blood rheometer. The parameters of sampling were analyzed. Results After the improvement, the sampling errors were reduced obviously (less than ?3%). The quota-sampling handling was more accurater. Conclusion The precision and reproducibility of the blood rheometer are ensured.