MiR-20b-5p modulates inflammation, apoptosis and angiogenesis in severe acute pancreatitis through autophagy by targeting AKT3.

BACKGROUND: Severe acute pancreatitis (SAP) is a common acute abdominal disease with high morbidity and mortality. However, the mechanism underlying SAP is still unclear. METHODS: Cerulean and LPS (Cer-LPS) was used to establish a rat model and an in vitro model of SAP. qRT-PCR, western blot and IHC were determined to analyse the expression of mRNA and proteins. IL-1ß, TNF-α and IL-6 levels were measured applying ELISA. H&E staining was determined to observe the pathological changes. Apoptosis was tested by AV-PI staining using flow cytometry. CCK8 assay was taken to detect cell viability. Cell migration was assessed by transwell assay. Tube formation assay was conducted to evaluate angiogenesis. Luciferase assay was used to detect relationship of miR-20b-5p and AKT3. RESULTS: MiR-20b-5p was lowly expressed in SAP models both in vivo and in vitro. Overexpression of miR-20b-5p restrained inflammation and apoptosis in Cer-LPS treated pancreatic acinar cells. Furthermore, miR-20b-5p promoted the angiogenesis of vascular endothelial cells, since the viability, migration and the capability of tube formation were increased by miR-20b-5p. Mechanically, miR-20b-5p directly targeted AKT3 to promote autophagy. Furthermore, miR-20b-5p could prevent the inflammation, apoptosis and enhance angiogenesis via enhancing autophagy, which was verified in vivo. CONCLUSION: This study demonstrated miR-20b-5p attenuates SAP through directly targeting AKT3 to regulate autophagy, subsequently inhibit inflammation and apoptosis, and promote angiogenesis. Our findings suggested a novel target of miR-20b-5p for the therapy of SAP.

Long Non-coding RNA FENDRR Modulates Autophagy Through Epigenetic Suppression of ATG7 via Binding PRC2 in Acute Pancreatitis.

Acute pancreatitis (AP) is an inflammatory, complicated pancreatic disease, carrying significant morbidity and mortality. However, the molecular and cellular mechanisms involved in AP pathogenesis remain to be elucidated. Here, we explore the role of FOXF1 adjacent non-coding developmental regulatory RNA (FENDRR) in AP progression. Caerulein with or without LPS- induced or taurolithocholic acid 3-sulfate (TLC-S)-induced AP mouse models and cell models were performed for the validation of FENDRR expression in vivo and in vitro, respectively. Histopathological examinations of pancreatic tissues were performed to evaluate the severity of AP. Transmission electron microscopy was utilized to visualize the autophagic vacuoles. siRNA specifically targeting FENDRR was further applied. Flow cytometry was employed to assess cell apoptosis. ELISA, immunoflureoscence, and western blotting analysis were also performed to determine the levels of inflammatory cytokines and autophagy activity. RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assays were carried out to reveal the epigenetic regulation of FENDRR on ATG7. Additionally, silencing FENDRR was also verified in AP mouse models. Higher FENDRR and impaired autophagy were displayed in both AP mouse models and cell models. FENDRR knockdown dramatically attenuated caerulein- or TLC-S-induced AR42J cells apoptosis and autophagy suppression. Further mechanistic experiments implied that the action of FENDRR is moderately attributable to its repression of ATG7 via direct interaction with the epigenetic repressor PRC2. Moreover, the silencing of FENDRR significantly induced the promotion of ATG7, thus alleviating the development of AP in vivo. Our study highlights FENDRR as a novel target that may contribute to AP progression, suggesting a therapeutic target for AP treatment.

SP1-induced ZFAS1 aggravates sepsis-induced cardiac dysfunction via miR-590-3p/NLRP3-mediated autophagy and pyroptosis.

BACKGROUND: Sepsis-induced cardiac dysfunction is one of the leading complications of sepsis, contributing to the high morbidity and mortality of septic patients. Several lines of evidence have demonstrated that autophagy and pyroptosis may be involved in septic cardiac dysfunction. In this study, we examined the impact of zinc finger antisense 1 (ZFAS1) on sepsis-induced myocardial dysfunction via regulating pyroptosis and autophagy. METHOD: Mice with cecal ligation and puncture (CLP)-induced sepsis was constructed in vivo. Myocardial injury was assessed by H&E staining, immunohistochemistry (IHC) for NLRP3, caspase 1, and interleukin (IL)-1ß, as well as ELISA assay for serum levels of creatine kinase (CK), CK-MB, tumor necrosis factor α (TNF-α), and IL-1ß. Primary cardiomyocytes exposed to lipopolysaccharide (LPS) were established to simulate sepsis-induced cardiac dysfunction in vitro. Cell viability was examined by MTT assay and concentration of TNF-α and IL-1ß was measured by ELISA. Flow cytometry, immunofluorescent staining and western blotting were performed to assess pyroptosis and autophagy. The transcriptional regulation of SP1 on ZFAS1 was determined using ChIP assay. Luciferase reporter assay was performed to verify the ZFAS1/miR-590-3p interaction. Besides, activation of AMPK/mTOR signaling was detected using western blotting. RESULTS: Highly expressed ZFAS1 was observed in sepsis-induced cardiac dysfunction in the in vivo and in vitro model. Knockdown of ZFAS1 robustly abolished LPS-induced pyroptosis and attenuated the inhibition of autophagy. SP1 was identified to be an essential transcription factor to positively regulate ZFAS1 expression. Moreover, miR-590-3p functioned as a downstream effector to reverse ZFAS1-mediated sepsis-induced cardiac dysfunction. AMPK/mTOR signaling was involved in miR-590-3p-regulated autophagy and pyroptosis of cardiomyocytes. Furthermore, the regulatory network of ZFAS1/miR-590-3p on AMPK/mTOR signaling was verified in vivo. CONCLUSION: ZFAS1, activated by SP1, aggravates the progression of sepsis-induced cardiac dysfunction via targeting miR-590-3p/AMPK/mTOR signaling-mediated autophagy and pyroptosis of cardiomyocytes.

Sesamin attenuates intestinal injury in sepsis via the HMGB1/TLR4/IL-33 signalling pathway.

CONTEXT: Sepsis is currently one of the leading causes of death in intensive care units (ICUs). Sesamin was previously reported to inhibit inflammation. However, no studies have revealed the impact of sesamin on sepsis. OBJECTIVE: We studied the mechanism underlying the effect of sesamin on the pathophysiology of sepsis through the HMGB1/TLR4/IL-33 signalling pathway. MATERIALS AND METHODS: Fifty male BALB/c mice (n = 10 per group) were used to establish a caecal ligation and puncture (CLP) mouse model, and given daily injections of sesamin at a low, middle, or high concentration (25, 50, or 100 µM) during the seven-day study period; survival curves were generated by the Kaplan-Meier method. H&E staining and TUNEL staining were performed to assess changes in intestinal morphology intestinal damage in the mouse intestinal epithelium. Molecules related to the HMGB1/TLR4/IL-33 pathway were assessed by RT-qPCR and Western blotting. RESULTS: We found mice in the sepsis group survived for only 4 days, while those treated with sesamin survived for 6-7 days. In addition, sesamin significantly relieved the increase in the levels of MPO (21%, 33.3%), MDA (40.5% and 31.6%), DAO (1.24-fold and 2.31-fold), and pro-inflammatory cytokines such as TNF-α (75% and 79%) and IL-6 (1-fold and 1.67-fold) 24 and 48 h after sepsis induction and downregulated the expression of HMGB1, TLR4, and IL-33 while upregulating the expression of ZO-1 and occludin. DISCUSSION AND CONCLUSIONS: Sesamin improved the 7-day survival rate of septic mice, suppressed the inflammatory response in sepsis through the HMGB-1/TLR4/IL-33 signalling pathway, and further alleviated intestinal injury.

miR-375 Inhibits Autophagy and Further Promotes Inflammation and Apoptosis of Acinar Cells by Targeting ATG7.

OBJECTIVES: MicroRNAs have been considered to be closely related with the development of severe acute pancreatitis (SAP), and microRNA-375 (miR-375) was believed to be a marker of SAP. We aim to investigate the role of miR-375 in regulating SP. METHODS: Cerulein and lipopolysaccharide were used to establish the models of SAP. AR42J cell line was chosen for study in vitro. Flow cytometry was applied for assessing apoptosis. The contents of inflammatory factors were detected with related enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction assays. Hematoxylin and eosin staining was applied to observe the pathological changes of pancreatic tissues. Immunohistochemistry analysis was conducted for investigating the expression of light chain 3. RESULTS: The level of miR-375 in pancreatitis tissues and cell lines was upregulated. Overexpression of miR-375 promoted inflammation and the apoptosis of acinar cells through inhibiting autophagy. The binding site between miR-375 and ATG7 was identified, and miR-375 could directly regulate the ATG7. microRNA-375 suppressed autophagy and promoted inflammation and the apoptosis of acinar cells via targeting ATG7. CONCLUSIONS: We proved that miR-375 could inhibit autophagy and promote inflammation and the apoptosis of acinar cells through regulating ATG7. This study first proves that miR-375 modulates the development of SAP through targeting ATG7.

Ginsenoside Rg1 Regulates SIRT1 to Ameliorate Sepsis-Induced Lung Inflammation and Injury via Inhibiting Endoplasmic Reticulum Stress and Inflammation.

OBJECTIVES: To investigate the protective effect of ginsenoside Rg1 on relieving sepsis-induced lung inflammation and injury in vivo and in vitro. METHODS: Cultured human pulmonary epithelial cell line A549 was challenged with LPS to induce cell injury, and CLP mouse model was generated to mimic clinical condition of systemic sepsis. Rg1 was applied to cells or animals at indicated dosage. Apoptosis of cultured cells was quantified by flow cytometry, along with ELISA for inflammatory cytokines in supernatant. For septic mice, lung tissue pathology was examined, plus ELISA assay for serum cytokines. Western blotting was used to examine the activation of inflammatory pathways and ER stress marker proteins in both cells and mouse lung tissues. Reactive oxygen species (ROS) level was quantified by DCFDA kit. RESULTS: Ginsenoside Rg1 treatment remarkably suppressed apoptosis rate of LPS-induced A549 cells, relieved mouse lung tissue damage, and elevated survival rate. Rg1 treatment also rescued cells from LPS-induced intracellular ROS. In both A549 cells and mouse lung tissues, further study showed that Rg1 perfusion significantly suppressed the secretion of inflammatory cytokines including tumor necrosis factor- (TNF-) alpha and interleukin- (IL-) 6 and relieved cells from ER stress as supported by decreased expression of marker proteins via upregulating sirtuin 1 (SIRT1). CONCLUSION: Our results showed that ginsenoside Rg1 treatment effectively relieved sepsis-induced lung injury in vitro and in vivo, mainly via upregulating SIRT1 to relieve ER stress and inflammation. These findings provide new insights for unrevealing potential candidate for severe sepsis accompanied with lung injury.

LncRNA MEG3 functions as a ceRNA in regulating hepatic lipogenesis by competitively binding to miR-21 with LRP6.

BACKGROUND: Hepatic lipogenesis dysregulation is essential for the development of non-alcoholic fatty liver disease (NAFLD). Emerging evidence indicates the importance of the involvement of long non-coding RNAs (LncRNAs) in lipogenesis. However, the specific mechanism underlying this process is not clear. OBJECTIVE: This study aimed to investigate the functional implication of LncRNA MEG3 (MEG3) in fatty degeneration of hepatocytes and in the pathogenesis of NAFLD. METHODS: The expression of MEG3 was analysed in in vitro and in vivo models of NAFLD, which were established by free fatty acid (FFA)-challenged HepG2 cells and high-fat diet-fed mice, respectively. Endogenous MEG3 was over-expressed by a specific pcDNA3.1-MEG3 to evaluate the regulatory function of MEG3 on triglyceride (TG)- and lipogenesis-related genes. Bioinformatic analysis was used to predict the target genes and binding sites, and the targeted regulatory relationship was verified with a dual luciferase assay. Finally, the possible pathway that regulates MEG3 was also evaluated. RESULTS: We found that the downregulation of MEG3 in vitro and in vivo models of NAFLD was negatively correlated with lipogenesis-related genes and that overexpression of MEG3 reversed FFA-induced lipid accumulation in HepG2 cells. miR-21 was upregulated in the FFA-challenged HepG2 cells and was physically associated with MEG3 in the process of lipogenesis. Our mechanistic studies demonstrated that MEG3 competitively binds to miR-21 with LRP6, followed by the inhibition of the mTOR pathway, which induces intracellular lipid accumulation. CONCLUSION: Our data are the first to document the working model of MEG3 functions as a potential hepatocyte lipid degeneration suppressor. MEG3 helps to alleviate lipid over-deposition, probably by binding to miR-21 to regulate the expression of LRP6. Our results suggest the potency of MEG3 as a biomarker for NAFLD and as a therapeutic target for treatment.

The CD40 rs1883832 Polymorphism Affects Sepsis Susceptibility and sCD40L Levels.

Sepsis is a severe and progressive disease characterized by systemic inflammatory response syndrome (SIRS). CD40 serves as a vital link between immune response and inflammation. This study was designed to investigate the potential association between a functional single-nucleotide polymorphism (SNP) of CD40 (rs1883832) and susceptibility to sepsis. We first performed a case-control study to explore the relationship between the CD40 rs1883832 polymorphism and sepsis. CD40 mRNA expression and protein expression were determined by real-time PCR and western blotting, respectively, in peripheral blood mononuclear cells (PBMCs) from sepsis patients and healthy controls. The plasma sCD40L levels in the two groups were measured by ELISA. The results showed that the frequencies of the TT genotype and the CD40 rs1883832 T allele were significantly higher in sepsis patients than in healthy controls. Plasma sCD40L levels were also significantly increased in sepsis patients. In addition, TT genotype carriers among sepsis patients displayed the highest CD40 expression at both the mRNA and protein levels, accompanied by the highest plasma sCD40L concentrations. In conclusion, the CD40 rs1883832 T allele acts as a risk factor for increased susceptibility to sepsis and may be involved in the process of sepsis through regulation of CD40 expression and plasma sCD40L levels.

Protective mechanism of Panax notoginseng saponins on rat hemorrhagic shock model in recovery stage.

To explore protective mechanism of Panax notoginseng saponins (PNS) on rat hemorrhagic shock model in recovery stage. 72 Wistar rats were selected and divided into control group, model group and PNS group with 24 rats in each group. 200 mg/kg PNS was injected intravenously at 60 min of hemorrhagic shock stage in PNS groups. Changes of endotoxin, MPO, IL-6, SOD, MDA and TNF α were observed at 30 and 120 min of recovery stage by ELISA; water content of lung and intestine was detected; HE staining was applied to observe morphological change of intestinal mucosa, kidney, liver and lung; western blot was used to detect intercellular adhesion molecule-1 (ICAM-1) level in lung tissue and intestine tissue. At 30 min and 120 min of recovery stage, MDA, MPO, endotoxin, TNF α and IL-6 levels significantly increased in model group compared with control group, however SOD level significantly decreased, the difference was statistically significant (P < 0.05); PNS dose-dependently decreased MDA, MPO, endotoxin, TNF α and IL-6 levels, and increased SOD level, which was statistically significant (P < 0.05); In results of water content detection, water content in lung tissue and intestine tissue was significantly higher than in control group, however, after being treated with PNS, the water content was significantly decreased; HE staining showed the morphologic change of lung tissue cells; Western blot showed that in lung tissue and intestine tissue, ICAM-1 level in model group was significantly higher than in control group, and it was lower in PNS group than in model group. PNS can increase SOD activity, decrease levels of MDA, endotoxin and MPO, decrease expression of TNF α and IL-6, and decrease water content in lung tissue and intestine tissue. Thus, PNS is protective to rat hemorrhagic shock model by anti oxidative stress and anti-inflammatory pathways, and ICAM-1 may play an important role in the mechanism.

[Activation of nuclear factor-kappa B and its modulalorg effects on intercellular adhesion molecule-1 expression in mice with dextran sulphate sodium-induced rat colitis].

OBJECTIVE: To investigate the changes in the activity of nuclear factor-kappaB (NF-kappa B) in mice with dextran sulphate sodium (DSS)-induced rat colitis and its modulalorg effect on intercellular adhesion molecule-1 (ICAM-1) expression. METHODS: Twenty normal male mice were randomized into DSS group and normal saline (NS) control group according to a matched-pair design. From days 1 to 7, the mice in DSS group were subjected to oral administration of 5%DSS solution, and from days 8 to 20, NS was given instead, for a total of 3 cycles. In the control group, only NS was administered. The colonic pathology was observed using HE staining and the mucosa 1 damage was scored for each mouse. The DNA-binding activity of NF-kappa B was tested by electrophoretic mobility shift assay, and the expressions of ICAM-1 and NF-kappa B p65 were detected using immunohistochemistry. RESULTS: The DNA-binding activity of NF-kappa B was significantly increased in DSS group as compared with NS group. ICAM-1 and p65 expressions were detected in the nuclei of the vascular endothelial and inflammatory cells, especially in the mucosa and submucosa, but such positive cells were seldom observed in NS group. A positive correlation was found between the DNA-binding activity of NF-kappa B and ICAM-1 expression. CONCLUSION: NF-kappa B activation is an important event in the development of DSS-induced colitis in that activated NF-kappa B upregulates ICAM-1 expression during colonic inflammation.

[Study on safety of apnea test in clinical determination of brain death].

OBJECTIVE: To determine the occurrence of severe complications such as hypotension, pulmonary artery hypertension as well as hypercapnia during apnea test in the affirmation of brain death and to investigate the possible effective prophylactic interventions. METHODS: Conventional apnea test was performed in 15 clinically suspected brain death patients. Stable circulation was achieved by adjusting preload only (n=4) or combined with titrating norepinephrine (NE, n=11). Blood gas was respectively analyzed before apnea test, 10 minutes after 100% fraction of oxygen (FiO(2)) ventilation, at each 2-minute interval after disconnecting ventilator and 5 minutes after reventilation. Hemodynamic parameters and dosage of NE were recorded at the same time points. Plasma concentration of lactate was measured before and at the end of apnea test. RESULTS: Spontaneous breath occurred in 1 case among 15 suspected brain death patients. Partial pressure of carbon dioxide (PaCO(2)) reached higher than 60 mm Hg (1 mm Hg=0.133 kPa) within 8 minutes in positive apnea test patients (P<0.01). pH significantly decreased (P<0.05), but partial pressure of oxygen (PaO(2)) maintained higher than 100 mm Hg during the test. Heart rate (HR) and mean artery pressure (MAP) slightly lowered (P>0.05), but pulmonary artery pressure (PAP) markedly elevated (P<0.05) at the end of the test in comparison with their base lines. On the other hand, HR and MAP increased in the negative apnea test case after ventilator disconnection. Severe arrhythmia events did not occur in all the cases. There was no change in the dosage of NE infusion, the range of which was 0.10-0.60 microg.kg(-1).min(-1) with the mean level of (0.23+/-0.17) microg.kg(-1).min(-1). The trend of HR, MAP, PAP and pulmonary arterial wedge pressure (PAWP) alterations was the same in patients no matter whether or not NE was used. HR, MAP and PAWP lowered, while PAP enhanced. Plasma lactate level was not significantly altered at the end of the test compared with the base line (from (1.41+/-0.05) mmol/L to (1.47+/-0.07) mmol/L). CONCLUSION: Adequate oxygenation could be maintained during conventional apnea test. The risk of inducing severe hypotension is low in non brain death patients. Based on adequate preload, low dose of NE infusion could prevent patients with high risk circulation instability from severe hypotension.

Preparation of enteric microsphere of oleanolic acid dihemiphthalate sodium by salting-out action using spherical crystallization technique.

AIM: Enteric microspheres were prepared to prevent the interaction of drug with gastric acid and to improve its bioavailability. METHODS: The enteric microspheres with a matrix structure were successfully produced using a spherical crystallization technique. Hydroxypropyl methylcellulose phthalate (HP-55), an enteric material, was coprecipitated with the drug by salting-out effect during the preparation process. A mixture of water and ethanol was chosen as a good solvent and dichloromethane was used as a bridging agent while 0.1 mol x L(-1) sodium chloride solution was selected as a poor solvent. RESULTS: It is the first time to prepare microspheres by making the water-soluble drug and water-insoluble excipient coprecipitated. In vivo test demonstrated that the drug absorption from the enteric oleanolic acid dihemiphthalate sodium (OADHPS) microspheres was significantly prolonged compared to that with OADHPS powder after a lag-time. Furthermore, the drug bioavailability was 181.6% greater than that with the OADHPS powder. CONCLUSION: The microspheres of water soluble drug could be prepared by using water phase replacing organic phase as poor solvent which decrease the quantity of organic solvent and benefit the environment prevention.

[Association of different alleles in interleukin-1 family genes with the coded cytokines production and outcome of sepsis].

OBJECTIVE: To investigate the association of alleles in interleukin-1(IL-1) family genes with IL-1alpha, IL-1beta, IL-1ra production as well as mRNA expression and the outcome of sepsis. METHODS: Sixty septic patients and equal number of healthy volunteers were enrolled in this study. Monocytes of healthy volunteers segregated by Ficoll were stimulated by lipopolysaccharide (LPS) in vitro. IL-1alpha, IL-1beta and IL-1ra mRNA expressions were semi-quantitatively analyzed with reverse transcription-polymerase chain reaction (RT-PCR). Cytokine production was determined with enzyme linked immunoadsorbent assay(ELISA). Alleles in IL-1A (intron 6, VNTR), IL-1B (-511, RLFP) and IL-1RN (intron 2, VNTR) were screened in all cases. RESULTS: The number of individuals carrying allele of IL-1RN2 was significantly greater in septic patients than that in healthy volunteers. Mortality in septic patients with IL-1RN2, compared with IL-1RN1, was markedly higher. Notably, IL-1ra production as well as mRNA expression of monocytes challenged with LPS was significantly higher in IL-1RN2 allele than in IL-1RN1 carriers. However, there was no difference in the coded gene expression between alleles of IL-1A1 and IL-1A2, also between IL-1B1 and IL-1B2. CONCLUSION: IL-1RN2 allele induces high IL-1ra expression and is closely with the outcome of patients in sepsis. It could be one of high risk genetic factors in septic patients.

A novel formulation design about water-insoluble oily drug: preparation of zedoary turmeric oil microspheres with self-emulsifying ability and evaluation in rabbits.

To enhance in vivo absorption of zedoary turmeric oil (ZTO) and develop new formulations of a water-insoluble oily drug, novel ZTO microspheres with self-emulsifying ability, called self-emulsifying microspheres here, were prepared in a liquid system by the quasi-emulsion solvent diffusion method. The microspheres containing hydroxypropyl methylcellulose acetate succinate (HPMCAS-LG), Talc and Aerosil 200 formed the stable surfactant-free emulsion when exposed to the pH 6.8 phosphate buffer, and were significantly different from the conventional self-emulsifying systems (SES), defined as isotropic mixtures of oil, surfactant and drug. Micromeritic properties, the efficiency of emulsification and the drug-release rate of the resultant microspheres were investigated. The bioavailability of the microspheres to the conventional self-emulsifying formulation for oral administration was evaluated in 12 healthy rabbits. A HPLC method was employed to determine the plasma concentration of Germacrone, an indexical component found in ZTO. The release rates of ZTO and Germacrone from the microspheres were enhanced significantly with increasing amounts of dispersing agents, and the efficiency of self-emulsification greatly depended on the HPMCAS-LG/Aerosil 200 ratio. The emulsion droplets released from the microspheres were much smaller than that of the conventional SES. The microsphere bioavailability (F) to the conventional SES for oral administration was 157.7%. Our method greatly improved the bioavailability of the water-insoluble oily drug from the self-emulsifying microspheres over the conventional SES and it is useful for the oily drug to form solid preparations.

[Evaluation of in vitro/in vivo correlation for three kinds of self-designed sustained-release nitrendipine formulations using deconvolution method].

AIM: To evaluate the in vitro/in vivo correlation for three kinds of self-designed sustained-release nitrendipine formulations using deconvolution method. METHODS: The characteristics of in vivo release were calculated by deconvolution method using the data of plasma concentration of three kinds of self-designed sustained-release nitrendipine formulations in healthy dogs, in which the in vivo results of nitrendipine solution after oral administrated to dogs were used as weight function. It was the compared with characteristics of in vitro release to assess the in vitro/in vivo correlations. RESULTS: The good correlations of in vitro/in vivo were shown in three kinds of self-designed sustained-release nitrendipine formulations using deconvolution method. CONCLUSION: The deconvolution method exhibited advantage in evaluation of in vitro/in vivo correlation for self-designed sustained-release nitrendipine formulations.

[Preparation of sustained-release nitrendipine microspheres with a solid dispersed structure in liquid system].

AIM: To prepare the sustained-release nitrendipine microspheres with a solid dispersed structure in liquid system. METHODS: The sustained-release nitrendipine microspheres with a solid dispersed structure was prepared in liquid system by combining spherical crystallization technique and solvent deposition method in one step. The resultant microspheres were evaluated for the recovery, micromeritc properties, incorporation efficiency. The factors of effect on the formation and the release rate of microspheres were also investigated. RESULTS: The recovery of microspheres (280-900 microns) was more than 70% and the bulk density was around 0.7 kg.L-1. The incorporation efficiency always exceeded 95%. The formation of microspheres was mainly affected by the amount of bridging liquid and the emulsifying agents in poor solvent. The release rate of nitrendipine from the microspheres could be controlled as desired by adjusting the ratio of talc to Eudragit RS PO in the formulation. CONCLUSION: The presented method was suitable for preparing sustained-release microspheres of a water insoluble drug.

Preparation of sustained-release nitrendipine microspheres with Eudragit RS and Aerosil using quasi-emulsion solvent diffusion method.

Sustained-release nitrendipine microspheres were prepared in liquid system by quasi-emulsion solvent diffusion method, in which the Aerosil was employed as an inert dispersing carrier to improve the dissolution rate of nitrendipine, and Eudragit RS as a retarding agent to control the release rate. The resultant microspheres were evaluated for the recovery, bulk density, average particle size, drug loading, and incorporation efficiency. And the factors affecting the formation of microspheres and the drug-release rate were investigated. It was observed by a scanning electron microscope (SEM) that the microspheres were finely spherical and uniform, and no entire nitrendipine crystals were observed visually. The results of X-ray diffraction indicated that nitrendipine in microspheres was disordered, suggesting that nitrendipine was highly dispersed in microspheres. The drug loading of microspheres was enhanced with increasing the ratio of drug to excipients, and the incorporation efficiency was always >90%. The formation of microspheres was mainly influenced by the amount of bridging liquid and sodium dodecyl sulfate (SDS) in poor solvent. The dissolution profiles could be modulated with adjusting the amount of retarding agent and dispersing carrier formulated.