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The aim of the current study was to explore the correlation between physical properties of wet masses and pellet quality by using powdered herbal slices as model drugs. Wet masses with 100 formulations were prepared by taking 20 kinds of powdered herbal slices as model drugs, microcrystalline cellulose as pelletization aid and five levels of added water as liquid binder. Physical properties of the wet masses such as hardness, adhesiveness, springiness, cohesiveness, chewiness, and resilience were measured by a texture analyzer. Meanwhile, the moisture retention capacities (MRC) of powdered herbal slices and wet masses were determined. Particles were classified after they were produced during spheronization. Principal component analysis, factor analysis and classification analysis were performed on the data. Wet masses could be classified into three groups by taking Ha as the first classification index and Ha/Sp as the second classification index. The correct rate of the classification was 91.00%. If Ha value of wet masses was greater than 15610 g, pellets of type ① would form, otherwise, pellets of type ② or type ③ would form based on Ha/Sp value. Then a classification plot of wet masses was developed to predict pellet formation of powdered herbal slices. Meanwhile, the probable mechanism of pellets formation during spheronisation was concluded in this study, which provided useful information to improve pellet quality.

The Andrographis herba extract (AHE), a traditional Chinese medicine (TCM), was developed to directly compactible powders by fluid bed coating with 6% to 12% hydroxypropyl methylcellulose (HPMC). The process-, instrument-, and formulation-related variables of the coating process were simultaneously optimized with the Hunter L18 screening design. Yield (Y1), compactibility (Y2), and angle of repose (Y3) were measured as the responses. The optimized variables were 50 °C for inlet air temperature, 150 m3/h for inlet airflow, 6.5 rpm for binder feed rate, 1.2 bar for spray atomisation pressure, L3 for air distributor plate, 1.5 cm for the distance between the air distributor plate and the bottom of guide cylinder, 6% for the ratio of HPMC to AHE, and 16% for the concentration of coating solution. The small errors (0.51% for Y1, 3.17% for Y2, and 4.78% for Y3) between the experimental and predicted values indicated the high degrees of prediction. All above results, together with the application data of the novel direct compaction-grade TCM extract powders, confirm that the design of experiment is effective to optimize the composition and the preparation process of composite materials mainly composed of TCM extracts. It is promising to produce high TCM-loading tablets with such composite materials by direct compaction.

In this study, a structured protocol for the classification of wet mass in extrusion-spheronization was developed to predict formation and pellet quality. The wet masses of 120 formulae were prepared taking microcrystalline celluloses as pelletization aid and lactose, hydroxypropyl methylcellulose grades, herbal medicines as model drugs. Physical properties of the wet masses such as hardness, adhesiveness, springiness, cohesiveness, chewiness, and resilience were tested, respectively, using a texture analyzer. Particles were produced by spheronization process, and the quality of spherical pellets was also evaluated. Data were analyzed by principal component analysis, factor analysis, and classification analysis. The wet masses could be classified into five groups taking the ratio of hardness to springiness (Ha/Sp) as the first classification index and chewiness, resilience as the second and the third classification index. The wet masses of different classification could correspondingly form the different shapes. So, a new protocol could be devised, for example, if the range of Ha/Sp of the wet masses was 30,992-47,689 g, at the same time, the value of chewiness was less than 4842, and the value of resilience was no more than 0.139; it would form spherical pellets under the experimental condition. These results demonstrate that the proposed protocol could be a valuable asset in a formulation development project to assess the physical properties of wet masses and to predict formation and pellet quality. So, the tedious and expensive pre-production (pre-formulation and optimization) work could be considerably reduced.

To quantify the physical characteristics of sticks of traditional Chinese medicine (TCM) honeyed pills prepared by the plastic molded method and the correlation of adhesiveness and plasticity-related parameters of sticks and quality of pills, in order to find major parameters and the appropriate range impacting pill quality.Sticks were detected by texture analyzer for their physical characteristic parameters such as hardness and compression action, and pills were observed by visual evaluation for their quality. The correlation of both data was determined by the stepwise discriminant analysis.Stick physical characteristic parameter l(CD) can exactly depict the adhesiveness, with the discriminant equation of Y0 - Y1 = 6.415 - 41.594l(CD). When Y0Y1, pills were scattered well; when Y0Y1, pills were adhesive with each other. Pills' physical characteristic parameters l(CD) and l(AC), Ar, Tr can exactly depict smoothness of pills, with the discriminant equation of Z0 - Z1 = -195.318 + 78.79l(AC) - 3 258. 982Ar + 3437.935Tr. When Z0Z1, pills were smooth on surface. When Z0Z1, pills were rough on surface.The stepwise discriminant analysis is made to show the obvious correlation between key physical characteristic parameters l(CD) and l(AC), Ar, Tr of sticks and appearance quality of pills, defining the molding process for preparing pills by the plastic molded and qualifying ranges of key physical characteristic parameters characterizing intermediate sticks, in order to provide theoretical basis for prescription screening and technical parameter adjustment for pills.