ABSTRACT
Traditional Chinese medicine (TCM) preparations have made tremendous progresses in modernization, whereas there exist relatively few researches pertaining to preparation structures. As demonstrated by the theory and practice of structure pharmaceutics, the structure properties of dosage forms have significant influences on the quality and efficacy of drugs, which might offer reference for the research and development of TCM dosage forms. With the application of synchrotron radiation X-ray micro-computed tomography (SR-μCT) and other novel technologies in recent years, researches in structure pharmaceutics have made huge advancement, which provide reference and methodology basis for the study of TCM preparations. The article generalized and summarized the recent progresses and methods in the structure researches of pharmaceutics and TCM preparations, and further explored the significance of the researches of structure of TCM preparations. It is expected to provide the basis for the dosage form design, production process improvement, and quality evaluation of TCM and promote the modernization of TCM preparations.
ABSTRACT
It is difficult to directly observe the structural transformation inside of soft capsules if their shells are opaque. This study was designed to noninvasively in situ measure the structural characteristics of the soft capsules and internal particle distributions to reveal the intrinsic quality of the soft capsules and develop a new technique for reverse engineering and the physical stability evaluation of the soft capsules. In this research, the CT projection images of soft capsules, namely, propolis soft capsules, were collected via synchrotron radiation X-ray micro computed tomography (SR-μCT). After three-dimensional reconstruction, the structural differences of the soft capsules under long-term test and accelerated test for 6 months were quantitatively analyzed by calculating the three-dimensional structure parameters such as volume, number and distribution of the particles inside and the thickness for the wall of the capsules. There were only a small number of particles evenly distributed in the soft capsules stored under common storage condition without layering. On the other hand, the shell wall of the soft capsule turned thinner locally at the occlusal portion and the particles with strong X-ray absorption were densely distributed at the edge of the capsule wall after the accelerated test. This study revealed that the structural parameters of soft capsules obtained by SR-μCT could be used to evaluate the influence of storage environment on the physical stability of soft capsules. The technology provides a new method for quality control and evaluation for the soft capsules.
ABSTRACT
The particle diameters of active pharmaceutical ingredient (API) and excipients are important factors to the quality of preparations and have great significances in the reverse engineering to brand products and the consistent evaluation of generic drugs. In this study, a novel method was established for particle size determination to identify the selected component and eliminate other interferential particles by comparing the microscopic images before and after fusion caused by controllable heating. Stearic acid (SA) particles in irregular and spherical shape were selected as a typical excipient to demonstrate the methodology, which were identified from the mixed particles based upon its melting characteristics to detect their particle sizes as well as the size distributions. In the same approach, the morphology and particle size of fenofibrate particles as API in tablets were analyzed. The results illustrated that the particle diameters and particle size distributions of the selected components in the mixture of particles can be detected via the hot-melting characteristics under the prerequisite of proper pretreatment to separate selected components from other particles in microscopic field. In conclusion, this research provides a practical approach for the reverse engineering purpose to brand products and the consistent evaluation of generic drugs.
ABSTRACT
Beads, a novel drug delivery system self-assembled by cyclodextrins (CDs) and oil, has potential applications in the solidification of oil drugs and improving the bioavailability of lipid-soluble drugs. However, very few researches were dedicated to the mechanism of beads formation. In this study, three-dimensional structures of beads were visualized and investigated using synchrotron radiation X-ray microcomputed tomography (SR-μCT). The structural changes of beads attributed by drying process were analyzed and confirmed via visualization results of SR-μCT. Productively, it was proposed that Pickering emulsion droplets obtained during beads formation process were spatially localized orderly. Moreover, the effects of loading lipid soluble drug, namely, vitamin K1, on the structural changes of beads were also analyzed. It is well known that the surface tension of oil phase could be changed by the addition of lipid soluble constituents. It was reasonable that the three-dimensional structure of beads might be altered during the drug loading of vitamin K1 into the beads. However, although the morphologies of beads were changed to some extent, the ordered Pickering emulsion droplets during the process of beads formation was successfully illustrated based on the SR-μCT results. Conclusively, according to the three-dimensional structural analysis of the beads, this study revealed the organized architecture for Pickering emulsion droplet assembly and beads formation in cyclodextrin semi-inclusion complex, which significantly complements the formation mechanism of beads, and provides a structural basis for the further study of beads.
ABSTRACT
Ibuprofen lipid pellets prepared by melting method could mask the bitter taste of the drug to some extent. The pellets were further coated with chitosan (cationic) and gelatin (anionic) by ionic interaction layerby- layer self-assembly (LBL) coating to improve masking effects. In this paper, the release percentage of drugs in short time (1 min) was utilized as an indicator for the taste-masking, and it had confirmed the LBL coating inhibited the release of model drug of ibuprofen. Synchrotron radiation-based Fourier-transform infrared spectromicroscopy (SR-FTIR) has been applied to investigate the material distributions on the cross section of pellets and film. Characteristic absorptions of the compositions were obtained by SR-FTIR single spectrum scanning. The distributions of the drug and materials in coated films were determined by SR-FTIR mapping. The FTIR absorptions of chitosan and gelatin on the surface of lipid pellets was examined to verify the existence of chitosan and gelatin on the surface and a film formed using SR-FTIR ratio analysis. Whilst pellets coated only by chitosan or gelatin did not show the typical absorption of chitosan or gelatin, which confirmed the effects of ionic interaction on the film forming process. In conclusion, the method of SR-FTIR established for the study of the existence and distribution of materials in coated film offers a new choice for researches on membranes/films in drug delivery systems and pharmaceutical preparations.
ABSTRACT
In this study, the Pickering emulsions were prepared using medium chain triglycerides (MCT) and α-cyclodextrin (α-CD) and the formation mechanism was studied by means of several physicochemical techniques. The MCT/α-CD microparticles, which stabilized the emulsions, were characterized by the measurement of interfacial tension and the contact angle (θow), powder X ray diffraction (XRD), scanning electron microscope (SEM), high performance liquid chromatography (HPLC), differential interference microscope (DIM), Cryo-scanning electron microscopy (Cryo-SEM). The physical stability of emulsions with different α-CD content in the continuous aqueous phase was investigated by determination of the droplet size and sedimentation rate, combined with the observation of droplet morphologies by the inverted phase contrast microscope. As a result, it was observed that the amphiphilic supramolecule of MCT and α-CD were indeed formed. Furthermore, MCT/α-CD microparticles formed by the aggregation of MCT/α-CD supramolecule absorbed at the oil/water interface, and then forming a membrane structure to stabilize emulsion. In addition, the average θow for the MCT/α-CD microparticles was (46.1±3.4)° which stabilized O/W emulsion. When the content of α-CD was increased in the continuous phase, there were more microparticles formed at the oil/water interface and in the continuous aqueous phase, which resulted in smaller particle size of droplet and higher viscosity of the continuous phase. In summary, the study suggest that α-CD/MCT/water emulsions were of O/W Pickering emulsions and the physical stability was better for emulsions with higher content of α-CD in the continuous phase.
ABSTRACT
The shape and structure of granules are controlled by the granulation process, which is one of the main factors to determine the nature of the solid dosage forms. In this article, three kinds of granules of a traditional Chinese medicine for improving appetite and promoting digestion, namely, Jianwei Granules, were prepared using granulation technologies as pendular granulation, high speed stirring granulation, and fluidized bed granulation and the powder properties of them were investigated. Meanwhile, synchrotron radiation X-ray computed micro tomography (SR-µCT) was applied to quantitatively determine the irregular internal structures of the granules. The three-dimensional (3D) structure models were obtained by 3D reconstruction, which were more accurately to characterize the three-dimensional structures of the particles through the quantitative data. The models were also used to quantitatively compare the structural differences of granules prepared by different granulation processes with the same formula, so as to characterize how the production process plays a role in the pharmaceutical behaviors of the granules. To focus on the irregularity of the particle structure, the box counting method was used to calculate the fractal dimensions of the granules. The results showed that the fractal dimension is more sensitive to reflect the minor differences in the structure features than the conventional parameters, and capable to specifically distinct granules in structure. It is proved that the fractal dimension could quantitatively characterize the structural information of irregular granules. It is the first time suggested by our research that the fractal dimension difference (Df,c) between two fractal dimension parameters, namely, the volume matrix fractal dimension and the surface matrix fractal dimension, is a new index to characterize granules with irregular structures and evaluate the effects of production processes on the structures of granules as a new indicator for the granulating process control and optimization.
Subject(s)
Drugs, Chinese Herbal , Fractals , Medicine, Chinese Traditional , Powders , Quantitative Structure-Activity Relationship , Synchrotrons , Technology, Pharmaceutical , Tomography, X-Ray ComputedABSTRACT
The release behavior of single pellet was investigated by LC/MS/MS method with tamsulosin hydrochloride (TSH) as the model drug of the research and then the pellets were divided into four groups according to the drug loading. Comparison of dissolution profiles of each group and capsule were performed using f1 and f2 factor methods to study the difference and similarity. The release profiles of single pellet, each group and capsule were analyzed using principle component analysis (PCA). The particle system was built through Matlab to get the target release profile. The result of this research demonstrated the release behavior of single pellet correlated well with the drug loading. While the dissolution profile of capsule as a reference, the similarity factor of dissolution profiles of the lower drug loading groups were 62.2, 67.1, 53.9, respectively and, 43.3 for highest drug loading group. The particle systems with different pellet distribution and same release profiles were built through release behavior of single pellet. It is of significance to investigate the release behavior of single pellets for studying the release regularity of multiple-unit drug delivery system.
Subject(s)
Capsules , Chemistry, Pharmaceutical , Chromatography, Liquid , Delayed-Action Preparations , Drug Delivery Systems , Drug Liberation , Principal Component Analysis , Sulfonamides , Chemistry , Tandem Mass Spectrometry , Technology, PharmaceuticalABSTRACT
The crystal form of solid substance had intrinsic correlation with its three dimensional crystal morphology. Based on the characterization of the three dimensional crystal morphology of clopidogrel bisulfate, this research is to establish a model based on the three dimensional morphological parameters. The granular samples composed of polymorphs of clopidogrel bisulfate and microcrystalline cellulose (MCC) were scanned by synchrotron radiation X-ray microscopic CT technology (SR-microCT) and the three dimensional structural models for which were constructed. Seven groups of three dimensional morphological parameters were calculated. Finally, the mathematical model was established with the multi-layer perception (MLP) artificial neutral network methods to identify and predict the polymorphs of clopidogrel bisulfate. The success rate of the model prediction for the polymorphs of clopidogrel bisulfate was 92.7% and the area under the ROC curve was 96.2%. The polymorphs of drugs could be identified and predicted through the numerical description of the three dimensional morphology. The volume, number of the vertices and the surface area were the major determinants for the identification of the polymorphs of clopidogrel bisulfate.
Subject(s)
Crystallization , Neural Networks, Computer , Platelet Aggregation Inhibitors , Chemistry , ROC Curve , Radiographic Image Interpretation, Computer-Assisted , Synchrotrons , Ticlopidine , Chemistry , Tomography, X-Ray ComputedABSTRACT
The purpose of this study is to investigate the applicability of a natural swelling matrix derived from boat-fruited sterculia seed (SMS) as the propellant of osmotic pump tablets. The sugar components, static swelling, water uptake and viscosity of SMS were determined and compared with that of polythylene oxide (WSR-N10 and WSR-303). Both ribavirin and glipizide were used as water-soluble and water-insoluble model drugs. Then, the monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide were prepared using SMS as the osmotically active substance and propellant. SMS was mainly composed of rhamnose, arabinose, xylose and galactose and exhibited relatively high swelling ability. The area of the disintegrated matrix tablet was 20.1 times as that at initial after swelling for 600 s. SMS swelled rapidly and was fully swelled (0.5%) in aqueous solution with relative low viscosity (3.66 +/- 0.03) mPa x s at 25 degrees C. The monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide using SMS as propellant exhibited typical drug release features of osmotic pumps. In conclusion, the swelling matrix derived from boat-fruited sterculia seed, with low viscosity and high swelling, is a potential propellant in the application of osmotic pump tablets.