Preparation of methotrexate-loaded, large, highly-porous PLLA microspheres by a high-voltage electrostatic antisolvent process.

A high-voltage (10 kV) electrostatic antisolvent process was used to prepare methotrexate (MTX)-loaded, large, highly-porous poly-L-lactide (PLLA) microspheres. MTX solution in dimethyl sulfoxide (DMSO) and PLLA solution in dichloromethane (DCM) were homogeneously mixed, and then ammonium bicarbonate (AB) aqueous solution was added. The mixed solution was emulsified by ultrasonication with Pluronic F127 (PF127) as an emulsion stabilizer. The emulsion was electrosprayed by the specific high-voltage apparatus and dropped into a 100 mL of ethanol, which acted as an antisolvent for the solute and extracted DMSO and DCM, causing the co-precipitation of PLLA and MTX, thus forming microspheres with AB aqueous micro-droplets uniformly inlaid. The obtained MTX-PLLA microspheres were subsequently lyophilized to obtain large, highly-porous MTX-PLLA microspheres, which exhibited an identifiable spherical shape and a rough surface furnished with open pores, with a mean particle size of 25.0 µm, mass median aerodynamic diameter of 3.1 ± 0.2 µm, fine-particle fraction of 57.1 ± 1.6 %, and porosity of 81.8 %; furthermore, they offered a sustained release of MTX. X-ray diffraction and Fourier transform-infrared spectra revealed that no crystallinity or alteration of chemical structure occurred during the high-voltage electrostatic antisolvent process, which in this study was proved to have great potential for preparing highly-porous drug-loaded polymer microspheres for use in pulmonary drug delivery.

[A clinical analysis of reninoma-induced hypertensive crisis associated with reversible posterior encephalopathy syndrome].

OBJECTIVE: Reninoma is a rare benign tumor of the renal juxtaglomerular cell apparatus that causes hypertension and hypokalemia via hypersecretion of renin, while it is extremely rare that reninoma induced hypertensive crisis with reversible posterior encephalopathy syndrome (RPES). To improve the clinical understanding for this disease, we conducted a case-analysis. METHODS: To analyze the clinical and pathological data of a case of reninoma-induced hypertensive crisis with reversible posterior encephalopathy syndrome, who was admitted to Peking University First Hospital in November, 2007 and follow-up. RESULTS: This was a 16-year old female patient, onset with suddenly spasm with loss of consciousness, while blood pressure stepped up to 210/140 mm Hg (1 mm Hg = 0.133 kPa), and the head magnetic resonance imaging (MRI) revealed "multiple long-T(2) signal", and hypokalemia (2.8 - 3.2 mmol/L), urine protein positive, ultrasound cardiogram revealed left ventricular hypertrophy, laboratory study revealed hyperreninism (38.23 ng·ml(-1)×h(-1), normal range 0.07 - 1.15 ng·ml(-1)×h(-1)) and hyperaldosteronism (660.9 ng/L, normal range 60 - 174 ng/L), abdominal CT-Scan revealed a mass at right kidney, blood pressure achieved safety range and the head MRI was rechecked and revealed "the abnormal long-T(2) signal disappeared". The clinical diagnosis was reninoma induced hypertensive crisis with RPES. The tumor was resected and the pathologic diagnosis was reninoma. The patient remained normotensive in the postoperative period without any medication. CONCLUSIONS: Reninoma represents a rare but surgically curable cause of hypertension, thus the clinical suspicion of it is very important in young patients. If the diagnosis is confirmed, positive treatment must be done immediately to improve the prognosis. The most common cause of RPES is hypertension, and the diagnosis depends on the distinctive head MRI. There is always a good prognosis with the decline of blood pressure rapidly.

Effects of different doses of metformin on bone mineral density and bone metabolism in elderly male patients with type 2 diabetes mellitus.

BACKGROUND: Diabetes is a chronic disease, which may cause various complications. Patients with diabetes are at high risk of bone and joint disorders, such as osteoporosis and bone fractures. In addition, it became widely accepted that diabetes has an important impact on bone metabolism. Metformin is a commonly used and effective first-line treatment for type 2 diabetes. Some glucose-lowering agents have been found to have an effect on bone metabolism. The present study explored if different doses of metformin have an effect on bone mineral density (BMD) and bone metabolism in type 2 diabetes. AIM: To investigate the effects of different doses of metformin on BMD and bone metabolism in elderly male patients with type 2 diabetes mellitus. METHODS: A total of 120 elderly male outpatients with type 2 diabetes mellitus who were admitted to our hospital were included in the study from July 2018 to June 2019. They were randomly assigned to an experimental group and a control group with 60 patients in each group. Patients in the experimental group were given high dose metformin four times a day 0.5 g each time for 12 wk. Patients in the control group were given low dose metformin orally twice a day 0.5 g each time for 12 wk. The changes in bone mineral density and bone metabolism before and after treatment and the efficacy rate of the treatment were compared between the two groups. RESULTS: There was no significant difference in the efficacy rate between the two groups (P > 0.05). Before the treatment, there was no significant difference in BMD and bone metabolism between the two groups (P > 0.05). However, after the treatment, BMD and bone metabolism were improved in the two groups. Moreover, BMD and 25-hydroxyvitamin D were significantly higher in the experimental group than in the control group, and N-terminal/midregion and ß-isomerized C-terminal telopeptides were significantly lower in the experimental group than in the control group (all P < 0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P > 0.05). CONCLUSION: Both high and low dose metformin can effectively control the blood glucose levels in elderly male patients with type 2 diabetes mellitus. However, the benefits of high dose metformin in improving BMD and bone metabolism level was more obvious in patients with type 2 diabetes mellitus.

Biological evaluation of Fe3O4-poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) magnetic microspheres prepared in supercritical CO2.

The biocompatibility of Fe3O4-poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) magnetic microspheres (Fe3O4-PLLA-PEG-PLLA MMPs) prepared in a process of suspension-enhanced dispersion by supercritical CO2 (SpEDS) was evaluated at various levels: cellular, molecular, and integrated. At the cellular level, the investigations of cytotoxicity and intracellular reactive oxygen species (ROS) generation indicate that the polymer-coated MMPs (2.0 mg/mL) had a higher toxicity than uncoated Fe3O4 nanoparticles, which led to about 20% loss of cell viability and an increase (0.2 fold) in ROS generation; the differences were not statistically significant (p > 0.05). However, an opposite phenomenon was observed in tests of hemolysis, which showed that the MMPs displayed the weakest hemolytic activity, namely only about 6% at the highest concentration (20 mg/mL). This phenomenon reveals that polymer-coated MMPs created less toxicity in red blood cells than uncoated Fe3O4 nanoparticles. At the molecular level, the MMPs were shown to be less genotoxic than Fe3O4 nanoparticles by measuring the micronucleus (MN) frequency in CHO-K1 cells. Furthermore, the mRNA expression of pro-inflammatory cytokines demonstrates that polymer-coated MMPs elicited a less intense secretion of pro-inflammatory cytokines than uncoated Fe3O4 nanoparticles. Acute toxicity tests of MMPs show quite a low toxicity, with an LD50 > 1575.00 mg/kg. The evidence of low toxicity presented in the results indicates that the Fe3O4-PLLA-PEG-PLLA MMPs from the SpEDS process have great potential for use in biomedical applications.

Formation of methotrexate-PLLA-PEG-PLLA composite microspheres by microencapsulation through a process of suspension-enhanced dispersion by supercritical CO2.

BACKGROUND: The aim of this study was to improve the drug loading, encapsulation efficiency, and sustained-release properties of supercritical CO(2)-based drug-loaded polymer carriers via a process of suspension-enhanced dispersion by supercritical CO(2) (SpEDS), which is an advanced version of solution-enhanced dispersion by supercritical CO(2) (SEDS). METHODS: Methotrexate nanoparticles were successfully microencapsulated into poly (L-lactide)-poly(ethylene glycol)-poly(L-lactide) (PLLA-PEG-PLLA) by SpEDS. Methotrexate nanoparticles were first prepared by SEDS, then suspended in PLLA-PEG-PLLA solution, and finally microencapsulated into PLLA-PEG-PLLA via SpEDS, where an "injector" was utilized in the suspension delivery system. RESULTS: After microencapsulation, the composite methotrexate (MTX)-PLLA-PEG-PLLA microspheres obtained had a mean particle size of 545 nm, drug loading of 13.7%, and an encapsulation efficiency of 39.2%. After an initial burst release, with around 65% of the total methotrexate being released in the first 3 hours, the MTX-PLLA-PEG-PLLA microspheres released methotrexate in a sustained manner, with 85% of the total methotrexate dose released within 23 hours and nearly 100% within 144 hours. CONCLUSION: Compared with a parallel study of the coprecipitation process, microencapsulation using SpEDS offered greater potential to manufacture drug-loaded polymer microspheres for a drug delivery system.