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Cocrystal separation technology is a technology that utilizes coformers to selectively form cocrystals with target compounds and separate them from mixed systems. Our study used puerarin (PUE), daidzein (DDZ), and genistein (GEN) as model drugs, which have similar structures and are the main isoflavones in Pueraria lobata root. The separation and purification processes in the modern traditional Chinese medicine (TCM) of these three components use conventional column chromatography, recrystallization, and other technologies, which have the issues of lengthy separation cycles, high solvent consumption, and inefficient preparation. Different with existing separation technology, our team used the early-found cocrystal separation method to design a step-by-step extraction and separation experiment of GEN-PUE-DDZ ternary mixture. Caffeine and L-proline were added to the mixed system in turn, GEN-caffeine cocrystal and PUE-proline cocrystal were prepared by suspension method. The cocrystals precipitated out of the solution. The purities of the GEN-caffeine cocrystal and the PUE-proline cocrystal could achieve 93% (the purity of GEN) and 99% (the purity of PUE). Besides, the purity of DDZ could also be increased by 6.76 times. This study proposed a simple operating, low cost and wide application range separation method different from the traditional separation method and realized the separation of structurally similar chemical components in TCM, laying a foundation for the application of cocrystal technology in the separation and refining of TCM.
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@#In order to guarantee the quality of traditional Chinese medicines (TCMs), the crystallization transformation of complex extracts of TCMs and the influence of solid form on their physicochemical properties were studied.The extract of total flavonoids from Pueraria lobata was taken as a model.Crystallization transformation happened when lofting under different conditions, and the intrinsic dissolution tests were carried out.It was found that humidity was the key factor to induce crystallization of total flavonoids from Pueraria lobata.The greater the wettability was, the more the crystallization was.The dissolution rate of total flavonoids from Pueraria lobata with the most crystallization amount significantly decreased by 96.51% compared to the sample without crystallization.After further simulating the preparation process of total flavonoids from Pueraria lobata, it was found that the wet granulation process with introduced water would also lead to crystallization and reduced dissolution rate.As for all crystallization samples, there was an inversely proportional relationship between the dissolution rates and the amount of crystallization.The risk of crystallization existed both in the storage and preparation process of TCM extracts.Crystallization would significantly affect the dissolution rate, and thus the quality of TCM products.In this study, the crystallization transformation of amorphous complex TCM extracts was discovered, and the effect of the crystallization transformation on its dissolution behavior was systematically studied, which provides a new research idea for assuring the quality of TCM products and promoting the improvement of TCM preparation level.
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@#In recent years, bio-metal organic frameworks (Bio-MOFs) synthesized with biocompatible ligands have been widely investigated as a potential drug delivery carrier due to their large specific surface area and porosity, rich host-guest intermolecular interactions, and good biocompatibility.In this review, we summarized the design methods of Bio-MOFs including structural and toxic factors, as well as a variety of drug loading methods including click chemistry, with particular focus on recent research advances in Bio-MOFs for pulmonary drug delivery systems, improving pharmaceutical properties of drugs, sustained and controlled drug release, stimulation response and targeted drug delivery systems.Finally, we summarized the bottlenecks that constrain the development of Bio-MOFs in clinical studies of actual pharmaceutical formulations and their future directions for approved formulations, aiming to provide some theoretical reference for promoting the application of Bio-MOFs in drug delivery systems.
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Mannitol-calcium chloride metal organic framework (MOF) cocrystal significantly improved the tabletability of β-mannitol and could be developed as a new tablet filler. However, mannitol monomer was found in the product during the scale-up production of the excipient, which significantly affected the functional properties of the excipient. In this study, we intend to quantify the multi-component eutectic system of mannitol-calcium chloride. In this experiment, the MOF cocrystal excipient mannitol-calcium chloride cocrystal was used as the model compound, and infrared spectrum was collected. Based on partial least squares regression (PLSR) method, the abnormal bands were removed and the spectrum was preprocessed by normalization. The quantitative correction model of mannitol-calcium chloride MOF cocrystal content in cocrystal excipients was established and compared by two different variable screening methods, genetic algorithm (GA) and competitive adaptive reweighting algorithm (CARS). Two different variable screening methods, GA method and CARS method, were used to screen out 160 and 14 variables, respectively. The mannitol-calcium chloride cocrystal model established by CARS-PLSR method had the best performance, and the average relative error (MRE) and corrected root mean square error (RMSEC) of the model were 0.008 8 and 0.892 5, respectively, the determination coefficient (R2) of the model was increased from 0.978 3 to 0.994 4. The quantitative method of eutectic system established in this study has high prediction accuracy, fast detection speed and good stability, which is of great significance for optimizing the preparation process conditions and quality control methods of such eutectic excipients.
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Solid dispersion, a dispersion system in which drug molecules are highly dispersed in carrier materials, has been commonly used to improve the solubility and dissolution rate of poorly soluble drugs. The miscibility between drug and carrier is crucial to improve the dissolution performance and stability of solid dispersion. Therefore, the selection of carrier types and the optimization of drug loading are very important. In the current study, the solubility parameter method and Flory-Huggins theory were used to predict the miscibility between olaparib (OLP) and different carriers (VA64, Soluplus, Plasdone S630 and Kollidon K29/32). Besides, the carrier material with good miscibility was experimentally screened by differential scanning calorimetry (DSC). The optimum of drug-carrier ratio was further performed based on the miscibility phase diagram of drug and carrier. Theoretical calculation and experimental evaluation showed that the miscibility of OLP and VA64 was the best, and the drug loading of 30% could meet the requirements of large drug loading and physical stability. Polarizing light microscope, X-ray powder diffraction, DSC and laser confocal Raman spectroscopy exhibited that OLP was amorphous form in the solid dispersion system. Powder dissolution test demonstrated that the solid dispersion showed significantly enhanced dissolution rate in comparison to crystalline OLP. In this study, theoretical calculation and experimental evaluation were used to screen the types of carriers and optimize the drug loading, which provides an efficient strategy for the selection of carrier and the amount used in solid dispersion.
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@#Topical preparations for skin, including the commonly used dosage forms of ointments, creams, gels, patches and plasters, are convenient and can avoid the first-pass effect of drugs.Rheological study, which describes the flow characteristics and mechanical properties of products relevant to their Critical Quality Attributes, has become the main focus for topical preparations.Liquid and solid behaviors of products are usually investigated via steady rheology as well as dynamic rheology.This article reviews the research on topical preparations for skin and the data analysis models based on two rheological methods, aiming to provide some references for the rheological evaluation of topical preparations.
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@#Lenvatinib mesylate (LF), a multi-target tyrosinase inhibitor mainly used in the treatment of a variety of cancers, has low oral bioavailability mainly due to its gelation during the dissolution process. In the current study, in order to enhance dissolution and eliminate gelation of LF, a supramolecular coamorphous system of LF-baicalein (BAI) (molar ratio, 1∶1) was prepared by rotary evaporation and characterized by PLM, PXRD, DSC and FTIR. Results indicated the formation of coamorphous system with a single Tg of 118 °C. Different from original LF crystal, no gelation phenomenon was observed during the dissolution of coamorphous LF-BAI. In addition, the dissolution rate of LF was increased by 2.2-fold after coamorphization. Meanwhile, the dissolution rate of the co-former BAI was also enhanced by more than 25.4-fold. Stability test showed that the prepared coamorphous system had a good physical stability for at least 90 days under 25 °C/ 60%RH and 40 °C /75%RH conditions.
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The solubility/dissolution, hygroscopicity and mechanical properties of drug candidates have a profound effect on oral bioavailability, processability and stability. The physicochemical properties of crystalline drug are closely related to inner crystal structure. Crystal engineering technologies, as strategies of altering the crystal structure and tailoring physicochemical properties at molecular level, possess the potential of enhancing the pharmaceutical performance of product. The current article reviewed the modification of drug solubility/dissolution, hygroscopicity and mechanical properties by crystal engineering technologies through polymorphic selection, amorphization/co-amorphization, as well as co-crystallization, which provided a reference for the applications of pharmaceutical crystallography in improving physicochemical properties and druggability.
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Lyotropic liquid crystal is an ordered system with various geometric shapes or three-dimensional structures formed by the interaction of amphiphilic molecules dissolved in polar solvents, and has the characteristics of excellent drug applicability, high drug loading, good bioadhesive property and high transdermal permeability. Through a comprehensive analysis of the research results in this research group and the related research reports of LLC drug delivery system, the authors systematically discussed the research value, development potential and research status of LLC in the field of new drug delivery system of traditional Chinese medicine(TCM), especially in the percutaneous and mucosal drug delivery system and the oral microparticle drug delivery system of TCM. At the same time, due to the current research field of TCM-LLC drug delivery system starts late, many of the basic research problems to be further perfect, this paper had carried on the induction summary to these problems, and put forward the research countermeasures:①the basic research of TCM-LLC drug delivery system should be strengthened by referencing the research experience and methods of LLC drug delivery system of single chemical component combined with TCM characteristics, ②the research on the release mechanism of the chemical components in TCM should be strengthened, and the basic research on the LLC drug delivery system of synchronized sustained release TCM should be carried out, ③development of new LLC materials applicable to TCM, ④the quality evaluation system of TCM-LLC should be improved, ⑤to explore the LLC preparation process suitable for industrialization.
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The aim of this study is to investigate the effect of nicotinamide (NIC) on the solubility/dissolution of a poorly soluble drug ibuprofen (IBU), and to explore the mechanism of the formed soluble complex by complexation model, fluorescence quenching and Raman spectroscope. The results showed that NIC could significantly improve the solubility of IBU, and exhibited an Ap type complexation profile. The calculated complexation constants of K1︰1 and K1︰2 were 0.24 and 4.00, respectively. In the solution, the fluorescent intensity of IBU gradually decreased with the increase of NIC, exhibiting the typical fluorescence-quenching phenomenon. The Raman spectrum showed stretching vibrations, bending vibrations, and rocking vibrations ascribed to benzene ring of IBU and pyridine ring of NIC disappeared or significantly shifted, suggested that the soluble complex was formed by dipole-dipole interaction force between the benzene group on IBU and pyridine group on NIC, resulting in the aqueous solubility enhancement of IBU. In comparison to IBU alone, the physical mixture of IBU and NIC showed significantly higher dissolution rate (1.6-fold) and extent.
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@#Baicalein(BE), a natural flavonoid mainly extracted from Radix Scutellaria, has comprehensive pharmacological actions such as anti-inflammation, anti-virus and anti-cancer activities. It belongs to BCS class II compound with relatively low oral bioavailability. The current study aims to improve its aqueous solubility and dissolution and hence to enhance its oral absorption by cocrystallization technique. Slurry crystallization method was employed to prepare baicalein cocrystal with co-former caffeine(CA), followed by physicochemical characterizations with DSC, XRPD and FTIR. Compared to BE and physical mixture of BE and CA, BE-CA cocrystal had a significantly higher dissolution of BE. In addition, in comparison to BE, this cocrystal achieved reduced time to peak(tmax)as well as significantly higher peak plasma concentrations(cmax)and area under the curve(AUCs)for both BE and its active metabolite baicalin(BI)in rats, suggesting enhanced the oral bioavailability of BE.
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@#Lyotropic liquid crystal system is formed by the amphiphilic molecules dissolving in polar solvents with a special geometric structure. Lamellar, cubic and hexagonal mesophases are some of the most common lyotropic liquid crystal systems. Recently, they have attracted much research attention because of their distinctive structures and physico-chemical properties(like strong bioadhesion, high permeability, low liquidity, and slow released drug), and have been widely used as carriers for drug delivery systems, especially in transdermal and mucosal fields. According to the research about lyotropic liquid crystal and nasal route of administration in our group, and the related references in recent years, we investigate the technical strategies about the using of lyotropic liquid crystal in transdermal and mucosal drug delivery system. Among them, we specially put the emphasis on the application prospects of lyotropic liquid crystal in the nasal mucosal administration, and then provide a theoretical basis and future research directions in the development of lyotropic liquid crystal in transdermal and mucosal administration fields.
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Tadalafil (TD), a phosphodiesterase-5 inhibitor for the treatment of erectile dysfunction, has a low oral bioavailability due to its extremely poorly aqueous solubility. The aim of this study was to enhance its solubility and dissolution by coamorphization with dapoxetine (DP), a selective serotonin reuptake inhibitor to manage premature ejaculation. Coamorphous TD-DP (molar ratio, 1:1) was prepared by solvent-evaporation method and characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR). The supersaturated dissolution of TD from coamorphous TD-DP was investigated in various aqueous media and compared to that of crystalline TD. In addition, physical stability of coamorphous system was also evaluated under the conditions of 40℃/75% relative humidity (RH) and 25℃/60% RH for 90 days. DSC thermogram and PXRD pattern indicated the formation of the coamorphous TD-DP. In comparison to original TD crystal, the dissolution of TD from coamorphous system were significantly enhanced in various media (water, 0.01 mol·L-1 HCl and pH 4.5 phosphate buffer). In addition, no crystallization phenomenon of the prepared coamorphous system was observed until 90 days' storage under 25℃/60% RH. However, when temperature and humidity were increased to 40℃/75% RH, the coamorphous TD-DP was recrystallized easily.
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In current study, adefovir dipivoxil (AD)-acetaminophen (AP) cocrystal (molar ratio, 1:1) was prepared by slow evaporation from acetonitrile, followed by physicochemical characterizations using differential scanning calorimetry, powder X-Ray diffraction and Fourier transform infrared spectroscopy. Molecular modeling showed that the phosphoester group of AD was connected with the amide group of AP through hydrogen bonds. In comparison to crystalline AD, the solubility and dissolution rate of AD from AD-AP cocrystal were significantly enhanced by 1.5-fold and 1.6-fold, respectively. In addition, based on the rat single-pass intestinal perfusion study, the permeabilities of AD in various intestinal sections (i.e., duodenum, jejunum, ileum and colon) were significantly improved (e.g., about 3-fold enhancement in duodenum) after cocrystallization with AP by inhibiting P-glyprotein mediated efflux of AD, which will benefit absorption in vivo and subsequent oral bioavailability of poorly permeable drug AD.
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As a new generation of anti-tumor drugs, taxanes has a good clinical efficacy in the treatment of ovarian cancer, breast cancer, non-small cell lung cancer, head and neck cancer. However, low bioavailability of oral administration from low water solubility and low permeability significantly limited the development of their oral applications. Currently, the marketed preparations were non-oral drug preparations, and the injection contained a large number of surfactants (cremophor EL or Tween 80) and organic solvents (ethanol), which could result in fluid retention, hypersensitivity and other side effects, as well as poor compliance. Oral preparation will be an ideal form for development of taxanes medicines. According to the research by our and other groups in recent years, we investigate the technical strategies enhancing the water solubility and absorptive permeability to improve their oral bioavailability. Among them, we emphasize the application prospects of crystallography technology, and provide a theoretical basis to guide future research in the development of oral preparations for taxanes.
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AIM To study the chemical constituents from Tibetan medicine Tinospora sinensis (Lour.)Merr..METHODS The ethyl acetate fraction of ethanol extract from T.sinensis was isolated and purified by silica,Sephadex LH-20,preparative HPLC column and recrystallization,then the structures of obtained compounds were identified by physicochemical properties and spectral data.RESULTS Nine compounds were isolated and identified as rutin (1),quercetin (2),kaempferol (3),luteolin (4),myricetin (5),paeonol (6),N-cisferuloyltyramine (7),myricetin-3-O-β-D-glucopyranoside (8),quercetin-3-O-α-L-rhamnoside (9).CONCLUSION All the compounds are isolated from this plant for the first time.
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AIM To study the chemical constituents from Tibetan medicine Tinospora sinensis (Lour.)Merr..METHODS The ethyl acetate fraction of ethanol extract from T.sinensis was isolated and purified by silica,Sephadex LH-20,preparative HPLC column and recrystallization,then the structures of obtained compounds were identified by physicochemical properties and spectral data.RESULTS Nine compounds were isolated and identified as rutin (1),quercetin (2),kaempferol (3),luteolin (4),myricetin (5),paeonol (6),N-cisferuloyltyramine (7),myricetin-3-O-β-D-glucopyranoside (8),quercetin-3-O-α-L-rhamnoside (9).CONCLUSION All the compounds are isolated from this plant for the first time.
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The purpose of this study was to investigate the thermodynamics of naringenin (NAR)-isonicotinamide (INT) cocrystal (stoichiometric ratio, 1∶2) formed in different solvents. The dissolution behavior of cocrystal was explored in the water. Solubility of NAR-INT cocrystals under various temperatures were measured, followed by fitting the complexation model to calculate the thermodynamic parameters solubility products (Ksp), complexation constants (K12) and Gibbs energy change (ΔG) of cocrystal during formation progress. Ternary phase diagrams (TPDs) of the NAR-INT-solvent systems under various temperatures were plotted. Based on the non-linear simulation, 1∶2 complexation model was well fitted to the NAR-INT cocrystal formation in ethanol, isopropanol and ethyl acetate, while no complexation model was more suitable for that in methanol. The cocrystallization reaction was exothermic and spontaneous (ΔG H S Ksp increased while K12 decreased when increasing temperature, suggesting that the two components could cocrystallize more easily at the lower temperature. In comparison to TPDs in other solvents, the area of homogeneous liquid phase in ethyl acetate was the smallest, indicating the easiest formation of NAR-INT cocrystal in ethyl acetate. The current study provides a theoretical foundation for preparation and optimization of scale-up NAR-INT cocrystals.
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Puerarin (PUE), an isoflavone with anti-inflammation, anti-oxidation and neuroprotection effects, has been widely applied to the treatment of cardiovascular diseases in clinics in China. In the current study, we reported that the active pharmaceutical ingredient (API) of marketed products was the PUE monohydrate (PUEMH). During its supersaturated dissolution, the PUE concentration quickly reached a plateau, followed by a gradually concentration decrease to another lower plateau. In order to explore the internal mechanism of above phenomenon, the solid residues after saturated dissolution test were characterized by powder X-ray diffraction (PXRD), thermal gravity analysis (TGA) and Karl Fisher titration (KFT). PXRD suggested that a novel PUE crystal different from PUEMH formed during its dissolution, the following TGA and KFT confirmed the generation of PUE dihydrate (PUEDH) with much lower solubility. Moreover, polyvinylpyrrolidones (PVPK12, PVPK30 and PVPK90) were added in the dissolution medium to investigate their potential inhibition effects on such crystal transformation during dissolution process. We observed that polymers could inhibit the transformation from PUEMH to PUEDH and result in much higher PUE concentration level than that in pure water.
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@#The purpose of this study was to investigate the formation thermodynamics of baicalein(BE)-nicotinamide(NCT)cocrystals in three solvents including ethyl acetate, acetone and trichloromethane. The solubilities of BE, NCT and BE-NCT in the above solvents at 25 °C were measured. Ternary phase diagrams(TPDs)of the BE-NCT-solvent systems were established. The non-linear fitting equation according to 1 ∶1 complexation mechanism of BE-NCT cocrystals demonstrated a good correlation between calculated and experiment data. ΔG0< 0 suggested that BE-NCT cocrystal formation was a spontaneous process. Among the organic solvents studied, the absolute value of ΔG0 in trichloromethane was significantly lower than that in the other two solvents. In addition, the cocrystallization zone in trichloromethane was far away from stoichiometric line. This study provides a theoretical foundation for solvent selection and preparation-condition optimization of BE-NCT cocrystals.