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1.
Org Biomol Chem ; 19(7): 1610-1615, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33528484

RESUMO

Highly enantiopure and bioactive δ-valerolactones and pyrazolones, bearing α-all-carbon quaternary stereocentres, were successfully and sequentially prepared via a one-pot procedure starting from readily available, inexpensive materials, catalysed by a new chiral squaramide under mild reaction conditions. An organocatalytic Michael reaction afforded the valerolactones, while a one-pot Michael-hydrazinolysis-imidization cascade yielded the pyrazolones. This procedure is economically efficient and environmentally benign.

2.
Zhongguo Zhong Yao Za Zhi ; 46(11): 2677-2685, 2021 Jun.
Artigo em Zh | MEDLINE | ID: mdl-34296563

RESUMO

Danggui Buxue Decoction is a classic prescription of Qi and blood tonification, which is mainly applied in treating fatigue, internal damage Qi weakness, blood deficiency, and outward going of floating Yang. Modern pharmacology shows that it can promote hematopoiesis, regulate immunity, and protect heart and cerebral vessels. The prescription, often used for the treatment of anemia and other diseases in clinic, is composed of Astragali Radix and Angelicae Sinensis Radix at a dosage ratio of 5∶1. It is a modern compound prescription for invigorating Qi and generating blood. Based on the review of the chemical constituents, pharmacological effects, and clinical applications of Danggui Buxue Decoction, its Q-marker was predicted and analyzed according to the "five principles" of Chinese medicine Q-marker--quality transmissibility and traceability, ingredient specificity, component validity, component measurabi-lity, and formula compatibility environment. The results suggested that calycosin, calycosin-7-O-ß-D-glucoside, formononetin, ononin, astragaloside A, ferulic acid, and ligustilide could be used as Q-markers of Danggui Buxue Decoction, which provides reference for establishing the quality system of Danggui Buxue Decoction.


Assuntos
Astrágalo , Medicamentos de Ervas Chinesas , Medicamentos de Ervas Chinesas/farmacologia , Raízes de Plantas
3.
Bioorg Med Chem Lett ; 30(16): 127324, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32631529

RESUMO

Neopeltolide, a natural product isolated from deep-water sponge specimen of the family neopeltidae, has been proven to be a novel inhibitor of cytochrome bc1. In this study, a series of neopeltolide derivatives was designed by replacing the 14-membered macrolactone with indole ring and confirmed by 1H NMR, 13C NMR, and HRMS. Based on the binding mode of 12h with bc1 complex, the IC50 values of compounds 16a-f (ranging from 0.70 to 1.46 µM) were improved significantly than the ester derivatives 12a-u by replacing the ester with amide linker. Subsequently, the molecular docking results indicated that compound 16e could form a π-π interaction with Phe274 and two H-bonds with Glu271 and His161 and the latter H-bond was found to account for its high activity. The present work accelerates the discovery of novel bc1 complex inhibitors to deal with the resistance that the existing bc1 complex inhibitors are facing and provides a valuable idea for the design of new fungicides.


Assuntos
Produtos Biológicos/farmacologia , Desenho de Fármacos , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Macrolídeos/farmacologia , Animais , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Relação Dose-Resposta a Droga , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Macrolídeos/química , Macrolídeos/isolamento & purificação , Simulação de Acoplamento Molecular , Estrutura Molecular , Poríferos/química , Relação Estrutura-Atividade
4.
Inorg Chem ; 59(10): 6729-6735, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32330013

RESUMO

Benzophenone (BP) is an ultraviolet filter (UVF) widely used in personal care products such as sunscreens and cosmetics. Excessive exposure to BP-type UVFs is a potential threat to human's health because of their endocrine-disrupting activity. Water stability of lanthanide compounds is crucial when they serve as luminescent sensors because of the practicality and recyclability. In this study, a water-stable luminescent Zn-Tb heterometallic coordination polymer was rationally designed and synthesized for rapid detection of BP. This material showed a high quenching effect, excellent selectivity, and fast response toward BP.

5.
Zhongguo Zhong Yao Za Zhi ; 45(12): 2765-2771, 2020 Jun.
Artigo em Zh | MEDLINE | ID: mdl-32627449

RESUMO

Suanzaoren Decoction is a classic prescription for nourishing the heart and liver, nourishing blood and tranquilizing the mind. It has the functions of sedation and hypnosis, anti-anxiety, anti-depression, anti-convulsion and so on. Modern clinic is mostly used to treat different types of insomnia, depression, neurasthenia, tension headache and vertigo. In this paper, the chemical consti-tuents, pharmacological effects and clinical application of Suanzaoren Decoction are reviewed. Based on this, the quality marker(Q-marker) of Suanzaoren Decoction was predicted and analyzed according to the "five principles" of Q-marker of traditional Chinese medicine--transmission and traceability, specificity, effectiveness, measurability and compatibility environment of compound prescriptions. The results indicated that jujuboside, spinosin, ferulic acid, senkyunolide Ⅰ, sarsasapogenin, mangiferin, liquiritoside and glycyrrhizic acid were predicted and analyzed, and those can be used as Q-markers of Suanzaoren Decoction. Subsequently, the above components can be selected as indicators to control and evaluate the quality of Suanzaoren Decoction and its preparations, and establish a quality traceability system.


Assuntos
Medicamentos de Ervas Chinesas , Distúrbios do Início e da Manutenção do Sono , Biomarcadores , Humanos , Medicina Tradicional Chinesa
6.
Cardiovasc Diabetol ; 18(1): 57, 2019 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-31054570

RESUMO

BACKGROUND: Dyslipidaemia has always been regarded as the cornerstone of arteriosclerosis and is related to the pathogenesis of renal insufficiency. However, it is unclear which routinely available lipid parameter is related to urinary albumin to creatinine ratio (UACR). The purpose of this study was to examine the lipid abnormalities associated with UACR in the general population in China. METHODS: The present study was nested in an ongoing Risk Evaluation of cAncers in Chinese diabetic Individuals: A lONgitudinal (REACTION) study, which was designed to demonstrate the association of abnormal glucose metabolism with the risk of cancer in the Chinese population. This cross-sectional study included 34, 569 subjects (11, 390 males and 23, 179 females) from 8 different regional community cohorts, with an average age of 57.9 years. The UACR data were divided into the < 25% group, the 25-49% group, the 50-74% group, and the ≥ 75% group according to the quartile division of the centre where the subjects visited. The lipid classes were defined according to the guidelines for the prevention and treatment of dyslipidaemia in Chinese adults. Multiple logistic regression analysis was used to evaluate the association of the lipid parameters and UACR. RESULTS: Multivariable regression analysis revealed that compared with the other lipid parameters, triglycerides (TG) showed an adjusted odds ratio that was significant in model 1-4. This relationship was attenuated after adjusting for Haemoglobin A1c (HbA1c) and blood pressure (BP), but TG ≥ 2.3 mmol/L was still significantly associated with UACR in total subjects and in both men and women (OR: 1.131, 95% CI 1.065-1.203, P < 0.001 in total subjects; OR: 1.134, 95% CI 1.022-1.258, P = 0.017 in men; OR: 1.129, 95% CI 1.046-1.219, P = 0.002 in women). In the stratified analysis, elevated TG was significantly associated with increased urinary albumin in subjects with eGFR ≥ 90 mL/min per 1.73 m2, 5.6 ≤ FBG < 7.0 or 7.8 ≤ PBG < 11.1 mmol/L, 24 ≤ BMI < 28 kg/m2, 120 ≤ SBP < 140 and/or 80 ≤ DBP < 90 mmHg. CONCLUSIONS: We conclude that high TG levels rather than total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or non-high-density lipoprotein cholesterol levels are associated with UACR in the general population in China.


Assuntos
Albuminúria/urina , Creatinina/urina , Dislipidemias/sangue , Triglicerídeos/sangue , Adulto , Idoso , Albuminúria/diagnóstico , Albuminúria/epidemiologia , Biomarcadores/sangue , Biomarcadores/urina , China/epidemiologia , Estudos Transversais , Dislipidemias/diagnóstico , Dislipidemias/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Regulação para Cima
7.
J Am Chem Soc ; 140(25): 7795-7798, 2018 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-29893555

RESUMO

Materials that possess coupled magnetic and electric properties are of significant interest because of their potential use in next-generation magnetoelectric devices such as digital information storage. To date, the magnetoelectric materials that have been studied in-depth have been limited mainly to inorganic oxides such as perovskite oxides. Molecular materials are a promising alternative because their magnetic and electric elements can be combined together at the molecular level via relatively simple molecular designs. Here, we report the coupling of magnetic and electric properties through a magnetodielectric (MD) effect in a single-crystal sample, which is constructed from dysprosium(III) single-molecule magnets (SMMs). The MD effect originates from intrinsic spin-lattice coupling of the dysprosium(III) ion within the sample. This is the first observation of the MD effect in a SMM-based material, which could pave the way toward the synthesis of advanced materials that combine distinct magnetic and electric properties using molecular chemistry for use in molecular devices with nanoscale size.

8.
Bioorg Med Chem Lett ; 28(8): 1330-1335, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29576509

RESUMO

Succinate-cytochrome c reductase (SCR) is composed of a mixture of mitochondrial complex II (succinate-ubiquinone oxidoreductase) and complex III (cytochrome bc1 complex). Meanwhile, complexes II and III are two promising targets of numerous antibiotics and fungicides. With an aim to identify new lead structures for SCR, complex II or III, a new series of 4-aryloxy-N-arylanilines were synthesized by introducing a 4-aryloxy phenyl group as one of the aryl groups in diaryl amines. With the economic Cu(OAc)2·H2O as the optimal copper promoter, a simple and facile protocol was utilized to afford 24 target products in 56-93% yields. Furthermore, extensive screening results suggested variable inhibitory activities of these compounds against SCR. Exceptionally, compounds 7k-7n showed excellent inhibition potency with their IC50 values in the nanomolar range, demonstrating higher potency than the commercial controls (penthiopyrad and azoxystrobin) by over one order of magnitude.


Assuntos
Compostos de Anilina/farmacologia , Inibidores Enzimáticos/farmacologia , Succinato Citocromo c Oxirredutase/antagonistas & inibidores , Compostos de Anilina/síntese química , Compostos de Anilina/química , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Estrutura Molecular , Pirazóis/farmacologia , Pirimidinas/farmacologia , Estrobilurinas/farmacologia , Tiofenos/farmacologia
9.
Pharm Res ; 34(2): 453-461, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28004315

RESUMO

PURPOSE: In this study, tocopherol based polymeric micelles were successfully prepared to enhance the anticancer effect of fisetin (FIS) in breast cancer cells. METHODS: The drug-loaded carrier was characterized in terms of physicochemical and in vivo parameters. RESULTS: Compared to FIS, FIS-TPN showed higher cellular uptake in MCF-7 breast cancer cells as revealed by CLSM and flow cytometry. The cytotoxicity assay results clearly showed that the free FIS and FIS-TPN exhibited a typical dose-dependent toxic effect in MCF-7 breast cancer cells. Especially, enhanced cytotoxic effect of FIS was observed when loaded in a nanocarrier. Free FIS induced a ~11% apoptosis whereas FIS-TPN induced a significantly greater apoptosis of ~20% by the end of 24 h. At 48 h, similar trend continued and free FIS showed ~30% of apoptosis whereas ~42% cell apoptosis was observed in FIS-TPN treated group. Notably, migration of cancer cell was significantly inhibited when treated with FIS-TPN formulations. The FIS-TPN significantly reduced to tumor burden and H&E staining showed the lowest tumor volume and higher cell apoptosis. CONCLUSIONS: All the findings suggest that the fisetin-loaded TPGS-PLA polymeric micelles serve as a potential candidate and promising alternative for the effective treatment of breast cancers.


Assuntos
Antineoplásicos/química , Neoplasias da Mama/tratamento farmacológico , Flavonoides/química , Poliésteres/química , Polímeros/química , alfa-Tocoferol/química , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Portadores de Fármacos/química , Feminino , Flavonoides/farmacologia , Flavonóis , Humanos , Células MCF-7 , Camundongos , Micelas , Polímeros/farmacologia , alfa-Tocoferol/farmacologia
10.
Chemistry ; 22(47): 17029-17036, 2016 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-27734535

RESUMO

A hexagonal porphyrin-based porous organic polymer, namely, CPF-1, was constructed by 3+2 ketoenamine condensation of the C2 -symmetric porphyrin diamine 5,15-bis(4-aminophenyl)-10,20-diphenylporphyrin and 1,3,5-triformylphloroglucinol. This material exhibits permanent porosity and excellent thermal and chemical stability. CPF-1 can be employed as a superior supporting substrate to immobilize Au nanoparticles (NPs) as a result of the strong interactions between Au NPs and the CPF support. An Au@CPF-1 hybrid was synthesized by an interfacial solution infiltration method with NaBH4 as reducing agent. Au NPs (5 nm) grew on CPF-1 and were distributed without aggregation. Moreover, Au@CPF-1 exhibits superior catalytic activity compared to many other reported Au-based catalysts for the reduction of 4-nitrophenol in the presence of NaBH4 . In addition, Au@CPF-1 has excellent stability and recyclability, and it can be reused for three successive reaction cycles without loss of activity. The dense distribution of phenyl rings on the channel walls of the CPF support can reasonably be regarded as the active sites that adsorb the 4-nitrophenol molecule through hydrogen-bonding and C-H⋅⋅⋅π interactions, as was confirmed by the X-ray structure of model compound DAPP-Benz.

11.
Appl Microbiol Biotechnol ; 100(15): 6859-6869, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27094186

RESUMO

A considerable proportion of Masson pine forests have been converted into eucalypt plantations in the last 30 years in Guangdong Province, subtropical China, for economic reasons, which may affect the ammonia-oxidizing archaea (AOA) community and the process of ammonia transformation. In order to determine the effects of forest conversion on AOA community, AOA communities in a Masson pine (Pinus massoniana) plantation and a eucalypt (Eucalyptus urophylla) plantation, which was converted from the Masson pine, were compared. Results showed that the land use change from the Masson pine to the eucalypt plantation decreased soil nutrient levels. A significant decrease of the potential nitrification rates (PNR) was also observed after the forest conversion (p < 5 %, n = 6). AOA were the only ammonia oxidizers in both plantations (no ammonia-oxidizing bacteria were detected). The detected AOA are affiliated with the genera Nitrosotalea and Nitrososphaera. A decrease of AOA abundance and an increase of the diversity were evident with the plantation conversion in the surface layer. AOA amoA gene diversity was negatively correlated with organic C and total N, respectively (p < 0.05, n = 12). AOA amoA gene abundance was negatively correlated with NH4 (+) and available P, respectively (p < 0.05, n = 12). However, AOA abundance was positively correlated with PNR, but not significantly (p < 0.05, n = 6), indicating AOA community change was only a partial reason for the decrease of PNR.


Assuntos
Amônia/metabolismo , Archaea/metabolismo , Eucalyptus , Pinus , Microbiologia do Solo , Agricultura , Archaea/genética , Biodiversidade , China , Florestas , Nitrificação , Oxirredução , Solo/química
12.
Yao Xue Xue Bao ; 49(10): 1451-6, 2014 Oct.
Artigo em Zh | MEDLINE | ID: mdl-25577878

RESUMO

To evaluate the differences of Ophiopogonjaponicus from different cultivations, the metabolomics based method was conducted to compare the effects of Hangmaidong and Chuanmaidong (Chinese name) on plasma endogenous metabolites of normal rats. Data were collected by ultra performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS), and were analyzed by multivariate statistical method, such as Principal Component Analysis and Orthogonal Signal Correction Partial Least Square Discriminant Analysis. Results revealed that the plasma metabolites profiling of low and middle dose group of Chuanmaidong were similar to the control group, but different from the high dose group obviously. Meanwhile the high, middle and low dose groups of Hangmaidong were different from control group notably, and the difference is dose dependent. Lysophosphatidylcholines, the possible endogenous metabolites which contribute to the classification most significantly, are closely related to cardiovascular system diseases. Compared with the group of Chuanmaidong, Hangmaidong has greater impact on the plasma metabolic profiling of normal rats. Hangmaidong and Chuanmaidong showed significant differences pharmacodynamically.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Metabolômica , Animais , Biomarcadores , Cromatografia Líquida de Alta Pressão , Análise dos Mínimos Quadrados , Espectrometria de Massas , Análise de Componente Principal , Ratos
13.
Oncol Lett ; 27(6): 268, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38659419

RESUMO

[This retracts the article DOI: 10.3892/ol.2016.5230.].

14.
Adv Sci (Weinh) ; 11(10): e2308220, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38233211

RESUMO

Single-molecule toroics are molecular magnets with vortex distribution of magnetic moments. The coupling between magnetic and electric properties such as the magnetodielectric effect will provide potential applications for them. Herein, the observation of significant magnetodielectric effect in a triangular Dy3 crystal with toroidal magnetic moment and multiple magnetic relaxations is reported. The analysis of magnetic and electric properties implies that the magnetodielectric effect is closely related to the strong spin-lattice coupling, magnetic interactions of Dy3+ ions, as well as molecular packing models.

15.
Arch Gynecol Obstet ; 288(5): 1145-8, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23661030

RESUMO

PURPOSE: Intercourse during menses is a sexual behavior practiced by 3-30 % of sexually active women. Defense responses of mucosal immunity in the female genital tract regulated by sex hormones would be impaired during menses. The present study seeks to clarify whether unprotected sexual activity during menses will increase the risk for antisperm antibody (ASA) production in female. METHODS: In this prospective study, 27 women who had a usual practice of vaginal intercourse during menses admitted in the First Affiliated Hospital of Jinan University with infertility were included, while 30 age-matched infertile women without this practice were set as controls. Indirect immunobead test (I-IBT) performed according to the World Health Organization (WHO) manual was used to measure the ASA levels. RESULTS: No case was revealed to develop significant ASA level. 6 of 27 women (22.2 %) in the case group and 1 of 30 women (3.3 %) in the control group were detected to be ASA subpositive, and a significant difference was found in the subpositive incidence between these two groups (P < 0.05). Among these 6 subpositive cases, 3 became pregnant in the subsequent 2-year follow-up after condom therapy for 6 months. CONCLUSIONS: Sperm exposure during menses is a risk factor for ASA production in female. Although a precisely causal linkage between ASA and infertility in these women cannot be drawn from the present data, the potential disadvantages of sexual activity during menses should still be given importance.


Assuntos
Anticorpos/sangue , Coito , Infertilidade Feminina/imunologia , Menstruação , Espermatozoides/imunologia , Adulto , Estudos de Casos e Controles , Preservativos , Feminino , Humanos , Infertilidade Feminina/terapia , Masculino , Estudos Prospectivos , Fatores de Risco , Adulto Jovem
16.
J Agric Food Chem ; 71(5): 2610-2615, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36696251

RESUMO

Succinate dehydrogenase (SDH, EC 1.3.5.1, also known as complex II) has been recognized as one of the most promising targets of fungicides. Here, based on the binding mode of pydiflumetofen with SDH, the carbon-carbon double bond was introduced into the chemical of pydiflumetofen and then produced the target compounds 6a-6o. The enzymatic inhibitory activity and structure-activity relationship (SAR) study showed that the 2-position and 4-position in terminal benzene were positive to increasing activity. Furthermore, fungicidal activity results in greenhouses indicated that compound 6o showed good control effects against wheat powdery mildew (WPM), cucumber powdery mildew (CPM), and southern corn rust (SCR), showing its broad-spectrum property. Especially, compound 6o exhibited 95 and 75% control effects against CPM and SCR at 6.25 mg/L, respectively, which are better than pydiflumetofen (80% control effects against CPM and 15% against SCR), indicating its potency that is worthy of further development.


Assuntos
Fungicidas Industriais , Fungicidas Industriais/química , Ácido Succínico , Succinato Desidrogenase , Relação Estrutura-Atividade , Pirazóis/química , Simulação de Acoplamento Molecular
17.
Nat Commun ; 14(1): 7901, 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38036549

RESUMO

Electrical control of magnetism in single-molecule magnets with peculiar quantum magnetic behaviours has promise for applications in molecular electronics and quantum computing. Nevertheless, such kind of magnetoelectric effects have not been achieved in such materials. Herein, we report the successful realization of significant magnetoelectric effects by introducing ferroelectricity into a dysprosium-based single-molecule magnet through spatial cooperation between flexible organic ligands and halide ions. The stair-shaped magnetization hysteresis loop, alternating current susceptibility, and magnetic relaxation can be directly modulated by applying a moderate electric field. Conversely, the electric polarization can be modulated by applying a small magnetic field. In addition, a resonant magnetodielectric effect is clearly observed, which enables detection of quantum tunnelling of magnetization by a simple electrical measurement. The integration of ferroelectricity into single-molecule magnets not only broadens the family of single-molecule magnets but also makes electrical detection and modulation of the quantum tunnelling of magnetization a reality.

18.
Dalton Trans ; 52(45): 16596-16600, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37955190

RESUMO

We report a method for synthesizing single-molecule magnets through a single-crystal to single-crystal transformation. This process yields two single-molecule magnets with similar triangular Dy3 cores but distinct solvents and space groups achieved via solvent exchange. Magnetic properties reveal that both Dy3 molecules exhibit similar toroidal moments but manifest diverse multiple magnetization dynamic behaviors owing to the spin-lattice coupling influence from different solvent molecules.

19.
Artigo em Inglês | MEDLINE | ID: mdl-36731219

RESUMO

As a result of global warming, the Mytilus coruscus living attached in the intertidal zone experience extreme and fluctuating changes in temperature, and extreme temperature changes are causing mass mortality of intertidal species. This study explores the transcriptional response of M. coruscus at different temperatures (18 °C, 26 °C, and 33 °C) and different times (0, 12, and 24 h) of action by analyzing the potential temperature of the intertidal zone. In response to high temperatures, several signaling pathways in M. coruscus, ribosome, endocytosis, endoplasmic reticulum stress, protein degradation, and lysosomes, interact to counter the adverse effects of high temperatures on protein homeostasis. Increased expression of key genes, including heat shock proteins (Hsp70, Hsp20, and Hsp110), Lysosome-associated membrane glycoprotein (LAMP), endoplasmic reticulum chaperone (BiP), and baculoviral IAP repeat-containing protein 7 (BIRC7), may further mitigate the effects of heat stress and delay mortality in M. coruscus. These results reveal changes in multiple signaling pathways involved in protein degradation during high-temperature stress, which will contribute to our overall understanding of the molecular mechanisms underlying the response of M. coruscus to high-temperature stress.


Assuntos
Mytilus , Animais , Mytilus/genética , Temperatura , Transcriptoma , Proteólise , Transdução de Sinais
20.
Langmuir ; 28(39): 13984-92, 2012 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-22937802

RESUMO

The microcosmic mechanisms of protein (recombinant human growth hormone, rhGH) incomplete release and stability from amphiphilic poly(monomethoxypolyethylene glycol-co-D,L-lactide) (mPEG-PLA, PELA) microspheres were investigated. PELA with different hydrophilicities (PELA-1, PELA-2, and PELA-3) based on various ratios of mPEG to PLA were employed to prepare microspheres exhibiting a narrow size distribution using a combined double emulsion and premix membrane emulsification method. The morphology, rhGH encapsulation efficiency, in vitro release profile, and rhGH stability of PELA microspheres during the release were characterized and compared in detail. It was found that increasing amounts of PLA enhanced the encapsulation efficiency of PELA microspheres but reduced both the release rate of rhGH and its stability. Contact angle, atomic force microscope (AFM), and quartz crystal microbalance with dissipation (QCM-D) techniques were first combined to elucidate the microcosmic mechanism of incomplete release by measuring the hydrophilicity of the PELA film and its interaction with rhGH. In addition, the pH change within the microsphere microenvironment was monitored by confocal laser scanning microscopy (CLSM) employing a pH-sensitive dye, which clarified the stability of rhGH during the release. These results suggested that PELA hydrophilicity played an important role in rhGH incomplete release and stability. Thus, the selection of suitable hydrophilic polymers with adequate PEG lengths is critical in the preparation of optimum protein drug sustained release systems. This present work is a first report elucidating the microcosmic mechanisms responsible for rhGH stability and its interaction with the microspheres. Importantly, this research demonstrated the application of promising new experimental methods in investigating the interaction between biomaterials and biomacromolecules, thus opening up a range of exciting potential applications in the biomedical field including drug delivery and tissue regeneration.


Assuntos
Hormônio do Crescimento Humano/química , Ácido Láctico/química , Microesferas , Polietilenoglicóis/química , Polímeros/química , Tensoativos/química , Humanos , Tamanho da Partícula , Poliésteres , Proteínas Recombinantes/química , Propriedades de Superfície
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