Advances in applications of molecular dynamics simulation techniques to the research of self-assembled nano-drug delivery systems / 药学学报

Molecular dynamics simulation technology relies on Newtonian mechanics to simulate the motion of molecular system of the real system by computer simulation. It has been used in the research of self-assembly processes illustration and macroscopic performance prediction of self-assembly nano-drug delivery systems (NDDS) in recent years, which contributes to the facilitation and accurate design of preparations. In this review, the definitions, catalogues, and the modules of molecular dynamics simulation techniques are introduced, and the current status of their applications are summarized in the acquisition and analysis of microscale information, such as particle size, morphology, the formation of microdomains, and molecule distribution of the self-assembly NDDS and the prediction of their macroscale performances, including stability, drug loading capacity, drug release kinetics and transmembrane properties. Moreover, the existing applications of the molecular dynamic simulation technology in the formulation prediction of self-assembled NDDS were also summarized. It is expected that the new strategies will promote the prediction of NDDS formulation and lay a theoretical foundation for an appropriate approach in NDDS studies and a reference for the wider application of molecular dynamics simulation technology in pharmaceutics.

The research progress on the structure pharmaceutics and dosage form structures of traditional Chinese medicines / 药学学报

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.

Preparation and evaluation of methotrexate sustained-release particles using crosslinked cyclodextrin metal-organic frameworks / 药学学报

Methotrexate (MTX) injection has a short half-life and significant toxic side effects. In order to overcome the demerits of MTX injection, MTX@COF was prepared for subcutaneous injection by loading MTX in crosslinked cyclodextrin metal-organic framework (COF) in this study. The cationic lipid material (2, 3-dioleoyl-propyl)-trimethylamine (DOTAP) was then coated on the MTX@COF surface by solvent evaporation. Different surface charge characteristics were observed in the coated MTX@COF@DOTAP with no significant change in particle morphology. The in vitro release behaviors of sustained-release particles were investigated in water and phosphate buffer (pH 7.4), and the in vivo release characteristics were evaluated for pharmacokinetics in rats. The in vitro release results showed that the cumulative release of MTX, MTX@COF and MTX@COF@DOTAP within 6 h was 92.70%, 36.31% and 18.19% in water, respectively; the cumulative release of MTX, MTX@COF and MTX@COF@DOTAP within 4 h was 90.82%, 79.37% and 58.30% in phosphate buffer, respectively; the results showed that MTX@COF can significantly delay the release of MTX, the modification to MTX@COF by DOTAP can further delay the release of MTX. Pharmacokinetic studies in rats showed that the mean retention time [MRT(0-t)] and the time to peak (Tmax) of the subcutaneous injection of MTX@COF@DOTAP group were significantly prolonged compared with the MTX@COF group and the MTX group. The area under the concentration-time curve [AUC(0-t)] of the MTX@COF@DOTAP subcutaneous injection group was 1.8 times high as that of the MTX group. In this study, MTX@COF@DOTAP particles had a certain sustained-release effect, and could prolong the bioavailability of MTX by subcutaneous injection, which provided a new idea for the development of new MTX dosage forms.

Preparation and stability evaluation of artemether-loaded mixed micelles composed of the sodium glycocholate and soybean lecithin / 药学学报

In this study, artemether (ARM)-loaded mixed micelles (MM) composed of the sodium glycocholate (SGC) and soybean lecithin (SL) were prepared by film dispersion method. The effects of hydration medium, SL mass ratio and total concentration of excipients on the solubilization of ARM were investigated and the stability of MM was evaluated. Results showed that the particle size distribution of SGC-SL-MM prepared by phosphate buffer solution (PBS, pH 7.4, 0.05 mol·L-1) was uniform, with an average size of 3.58 ± 0.14 nm and the polydispersity index (PDI) value was 0.16 ± 0.04. The solubility of ARM increased significantly from 0.64 ± 0.04 mg·mL-1 to 13.7 ± 0.13 mg·mL-1 along with the concentration of total excipient increasing from 1.0% to 30.0% (w/w). The calculated results of Arrhenius parameter and storage stability showed that the degradation rate constant of ARM in MM was smaller than that in acetonitrile-PBS (pH 7.4) at either 37 ℃ or 60 ℃. The experimental ARM-MM was clear after storing for two months at 25 ℃ and the degradation of ARM was less than 7.0%. In conclusion, the SGC-SL-MM can not only improve the solubility of ARM in aqueous solution, but also improve its chemical stability in aqueous solution at low temperature.

In situ characterization of structural change and internal particle distributions of soft capsules based on synchrotron radiation X-ray micro computed tomography / 药学学报

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.

Determination of particle size and particle size distribution of selected component in mixed powders by its melting characteristics / 药学学报

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.

Three-dimensional structure of beads self-assembled by cyclodextrin using synchrotron radiation X-ray microcomputed tomography / 药学学报

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.

Response of volatiles of Artemisiae Argyi Folium to climatic factors / 中国中药杂志

Combined headspace solid-phase microextraction with gas chromatography-mass spectrometry (HS-SPME-GC-MS), this paper studied the volatiles of Artemisiae Argyi Folium that respectively collected from Kongdong, Huanglong, Ankang, Qichun and Tongbai，and then explored the influence of climatic factors on the main components of the volatiles. The results showed that 54, 52, 57, 47 and 55 compounds were respectively identified from the leaves from five regions, mainly consist of monoterpenes, sesquiterpenoids and their oxygen-containing derivatives, a few aldehydes, alkanes and benzenes. It is different that the volatiles of Artemisiae Argyi Folium that collected in different habitats, neither composition nor content. There are total 18 kinds of compounds that exist in all five leaves. Eucalyptol, camphor, terpinen-4-ol, eugenol and caryophyllene could be considered to be the main conponents because of their efficacy or toxicity and relatively high content. Grey correlation analysis shows that the annual lowest temperature and annual sunshine duration have a great influence on the content of eucalyptol and camphor; the effect of annual precipitation and annual accumulated temperature on the content of terpinen-4-ol and caryophyllene was relatively significant; while the annual sunshine duration and the annual highest temperature are the main influencing factors for eugenol. The research suggests that long-day and extreme temperature may be more conductive to the accumulation of volatiles. According to the laws of effect of climatic factors on volatiles, we can optimize the cultivation conditions and select suitable locality to improve the quality of Artemisiae Argyi Folium.

Structure-based strategy for consistency evaluation of dosage forms / 药学学报

Strategies and techniques are extremely important to improve the evaluation efficiency and fully guarantee the consistency of dosage forms. For preparations with a structural feature as solid dosage forms and particulate dispersion systems, the structures of dosage forms are the outcome of the specific formulation and production process, which determine the drug delivery behaviors as well as the pharmacokinetics of the dosage forms. Conventional techniques failed to quantitatively determine the structures of dosage forms. Synchrotron radiation micro-computed tomography is a new generation of structural quantitative characterization technology in revealing the internal structure of dosage forms with unprecedented capability for quantitative characterization of the static and dynamic structures of dosage forms, enabling to reversely analyze the production process and identify the structure differences between the generics and brand products. Based on synchrotron radiation micro-computed tomography methodology researches and applications in static structures (powders, particulate systems, tablets, films, membranes, etc.), dynamic structures (hydration) and de-formulation of production process, we have classified the structures of dosage forms into four levels from macro-scope to molecular level as dosage forms, granular intermediates for formulation, dynamic structure and molecular structures, and proposed dosage form structure based new strategy for consistency evaluation. Along with conventional dissolution/ release behavior similarity, the internal structure consistency ensures high consistency between the brand product and the generics.

Taste-masking mechanism of layer-by-layer self-assembly coating investigated by synchrotron radiation-based Fourier-transform infrared spectromicroscopy / 药学学报

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.

Formation mechanism of Pickering emulsions induced by self-assembly of medium chain triglycerides and α-cyclodextrin / 药学学报

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.

Quantitative structure characteristics and fractal dimension of Chinese medicine granules measured by synchrotron radiation X-ray computed micro tomography / 药学学报

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.

Determination of the interaction kinetics between meloxicam and β-cyclodextrin using the quantitative high-performance affinity chromatography coupled with mass spectrometry / 药学学报

The association rate constant and dissociation rate constant are important parameters of the drug-cyclodextrin supermolecule systems, which determine the dissociation of drugs from the complex and the further in vivo absorption of drugs. However, the current studies of drug-cyclodextrin interactions mostly focus on the thermodynamic parameter of equilibrium constants (K). In this paper, a method based on quantitative high performance affinity chromatography coupled with mass spectrometry was developed to determine the apparent dissociation rate constant (k(off,app)) of drug-cyclodextrin supermolecule systems. This method was employed to measure the k(off,app) of meloxicam and acetaminophen. Firstly, chromatographic peaks of drugs and non-retained solute (uracil) on β-cyclodextrin column at different flow rates were acquired, and the retention time and variance values were obtained via the fitting the peaks. Then, the plate heights of drugs (H(R)) and uracil (H(M,C)) were calculated. The plate height of theoretical non-retained solute (H(M,T)) was calculated based on the differences of diffusion coefficient and the stagnant mobile phase mass transfer between drugs and uracil. Finally, the k(off,app) was calculated from the slope of the regression equation between (H(R)-H(M,T)) and uk/(1+k)2, (0.13 ± 0.00) s(-1) and (4.83 ± 0.10) s(-1) for meloxicam and acetaminophen (control drug), respectively. In addition, the apparent association rate constant (k(on,app)) was also calculated through the product of K (12.53 L x mol(-1)) and k(off,app). In summary, it has been proved that the method established in our study was simple, efficiently fast and reproducible for investigation on the kinetics of drug-cyclodextrin interactions.

Synergetic taste masking of lipid coating and beta-cyclodextrin inclusion / 药学学报

Paracetamol was used as a model drug in this study to investigate the synergetic effects of lipid coating and beta-cyclodextrin (beta-CD) inclusion for masking the bitter taste of poorly soluble drugs. To control the concentration as low as possible of the free drug which produced a bitter taste, a kinetic model was established to calculate the drug distribution theoretically among the free drug in medium, lipid coated particles and molecular inclusion on the basis of the preparation and characterization of the lipid microspheres, so as to select the proper amount of beta-CD. Finally, the synergetic drug delivery systems were prepared and characterized by 1H nuclear magnetic resonance (1H NMR), molecular simulation and the electronic tongue. As a result, the drug release rate constant (k) of the lipid microspheres coated with octadecanol was determined as 0.001 270 s(-1). Then, the synergetic drug delivery systems were prepared with the ratio of 6.74 : 1 (w/w) for beta-CD and paracetamol. The chemical shift values for the fingerprint peaks of paracetamol all increased and hydrogen bonds were formed between the oxygen on the phenolic hydroxyl group, the nitrogen on the imino in paracetamol and the hydrogens on the hydroxyl groups in beta-CD. The results tested by the electronic tongue indicated that the paracetamol, lipid microspheres, beta-CD inclusion and their mixture showed different taste characteristics, with the bitterness order of the synergetic drug delivery systems approximately lipid microspheres < beta-CD inclusion < paracetamol, which confirmed the synergetic taste masking effects of lipid coating and beta-CD molecular inclusion. In summary, the synergetic taste masking was jointly achieved through the retard of the drug release by the lipid coating and the inclusion of the free paracetamol by beta-CD through hydrogen bonds.

Release kinetics of single pellets and the multi-pellet system of tamsulosin hydrochloride sustained release pellets / 药学学报

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.

Real-time UV imaging of chloramphenicol intrinsic dissolution characteristics from ophthalmic in situ gel / 药学学报

In this paper, chloramphenicol was selected as a model drug to prepare in situ gels. The intrinsic dissolution rate of chloramphenicol from in situ gel was evaluated using the surface dissolution imaging system. The results indicated that intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel decreased significantly when the poloxamer concentration increased. The addition of the thickener reduced the intrinsic dissolution rate of chloramphenicol thermosensitive gel, wherein carbomer had the most impact. Different dilution ratios of simulated tear fluid greatly affected gel temperature, and had little influence on the intrinsic dissolution rate of chloramphenicol from the thermosensitive in situ gel. The pH of simulated tear fluid had little influence on the intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel. For the pH sensitive in situ gel, the dissolution rates of chloramphenicol in weak acidic and neutral simulated tear fluids were slower than that in weak alkaline simulated tear fluid. In conclusion, the intrinsic dissolution of chloramphenicol from in situ gel was dependent on formulation and physiological factors. With advantages of small volume sample required and rapid detection, the UV imaging method can be an efficient tool for the evaluation of drug release characteristics of ophthalmic in situ gel.

Applicability of a natural swelling matrix as the propellant of osmotic pump tablets / 药学学报

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.

Identification of the polymorphs of clopidogrel bisulfate based on the steric morphology parameters of crystals / 药学学报

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.

An oligopeptide improves solubility of paclitaxel by non-covalent interaction / 药学学报

Based on the principle of non-covalent interactions between oligopeptides and paclitaxel for improving the solubility of paclitaxel, an oligopeptide, N terminal-W(L)-FFGREKD-C terminal (W8), was designed and the solubilization effect of W8 on paclitaxel was detected through experiments. The binding efficiency and the possible optimal conformation were optimized by molecular docking program. The solubilization effect of W8 on paclitaxel was determined by RP-HPLC. And the solubilization mechanism of oligopeptide to paclitaxel was proposed at molecular level. It was indicated from the docking result that there existed pi-pi interactions and several hydrogen-bond interactions between the oligopeptide and paclitaxel. After being solubilized by the oligopeptide, the aqueous solubility of paclitaxel was increased to 28 times. This study provided basis for further research of the solubilization of paclitaxel by oligopeptide and confirmed a novel approach for the design of safe oligopeptide solubilizing excipient.

Preparation and characterization of dihydroartemisinin/ hydroxypropyl-beta-cyclodextrin inclusion complex / 药学学报

To optimize the preparation method of the complex of dihydroartemisinin (DHA) included by hydroxypropyl-beta-cyclodextrin (HP-beta-CD), the molar ratio of DHA and HP-beta-CD, inclusion temperature and inclusion time were optimized by the orthogonal design method with the inclusion drug yield and drug loading as the evaluation indexes. The IR spectrum, DSC and PXRD analyses were employed to characterize the complex and the molecular simulation was processed to investigate the tendency of complex formation. The optimized molar ratio of DHA and HP-beta-CD was 1 : 5, and the optimized preparation was performed under 50 degrees C for 1 h. The IR spectrum, DSC and PXRD analyses indicated the formation of the complex. The low binding free energy and the high solvent accessible surface obtained by molecular simulation showed that DHA could be included by HP-beta-CD and its solubility could be improved significantly. In conclusion, the optimized conditions for the preparation of DHA-HP-beta-CD complex provide a theoretical and experimental basis for further scale-up research.