Solid lipid microparticles of erythromycin ethyl succinate were prepared using solvent evaporation method to improve its bioavailability and efficacy. The solvent was allowed to evaporate after which the various entra...Solid lipid microparticles of erythromycin ethyl succinate were prepared using solvent evaporation method to improve its bioavailability and efficacy. The solvent was allowed to evaporate after which the various entrapments were determined; the best entrapment was used in the in vivo studies to determine the bioavailability and efficacy. This study was done with albino mice. The best entrapment obtained was 83% with a loading capacity of 2.9% （Batch D） and was used in comparison with the unformulated drug to check for the in vivo efficacy. The results show higher efficacy with the formulated drug than with the pure drug both in vitro and in vivo. The in vitro test results were better despite that some enzymes which need to act on the solid lipid microparticles were not present in the in vitro assay and could lead to a reduction in the release of the drugs. In conclusion, there was improvement in efficacy, and hence bioavailability.展开更多
The aim of this work was to increase the efficacy of erythromycin ethyl succinate by encapsulation in beeswax lipid matrix using Myrj 52 as emulsifier. Different batches of SLM＇s （solid-lipid microparticles） were f...The aim of this work was to increase the efficacy of erythromycin ethyl succinate by encapsulation in beeswax lipid matrix using Myrj 52 as emulsifier. Different batches of SLM＇s （solid-lipid microparticles） were formulated and stable ones were selected. The encapsulation efficiency and loading capacities were calculated. The batch with the highest loading capacity was used for further assays. The particle size was determined by light microscopy. The sensitivity of different clinical bacterial isolates to erythromycin was tested using in vitro cultures and E. coli was selected for efficacy tests. The activity of the formulated drug was tested in the in vitro culture and compared to that of the unformulated drug. White albino mice were infected with E. coli and left for one day to develop significant bacteremia. They were then divided into 4 groups （n = 4） and treated with the formulation and unformulated drug at a dose of 7.14 mg/kg 8 hourly for 56 hours. A third group was given SLM＇s that do not contain drug, while another group was left untreated. The selected batch has an encapsulation efficiency of 94.83% with a loading capacity of 3.88%. The particle size was 17 ± 4 μm. At the end of the three day period of treatment, the group treated with unformulated erythromycin had much stooling anti weakness in the mice, and some deaths were recorded, while that treated with the formulation had 33.8% bacteremia and the clinical signs had largely subsided. The other two groups recorded deaths the following day after bacteremia induction. The results show marked improvement in efficacy of erythromycin ethyl succinate by formulation in SLMs with beeswax and lecithin as lipid matrix.展开更多
Nanocapsule-based targeted delivery and stimulus-responsive release can increase drug effectiveness, while reducing the side effects of the drug. However, difficulties in the scale-up synthesis, fast burst release, an...Nanocapsule-based targeted delivery and stimulus-responsive release can increase drug effectiveness, while reducing the side effects of the drug. However, difficulties in the scale-up synthesis, fast burst release, and low degradability, could hamper the translation of drug nanocapsules from lab to clinic. Here we have controllably functionalized the biodegradable and widely available polysuccinimide, in order to obtain an amphiphilic poly（amino acid）. Using this polymer, we designed nanocapsules （〈 100 nm） for hydrophobic drug delivery, which could facilitate tumor targeting, hydrogen bond-based pH-responsive release, and real-time fluorescence tracking, in the second near-infrared region. This method is versatile, eco-friendly, and easy to scale up at low costs. In addition, this system can carry a cocktail of drugs, obtained by loading multiple anticancer drugs to the same vehicle. Our nanocapsules were observed to be stable in blood vessels （pH = 7.4）, and the pH-responsive release （pH = 5.0 in lysosome） was sustained. The chemotherapy results in tumor-xenografted mice suggested that our nanocapsule was safe and efficient, and may be a useful tool for drug delivery.展开更多
Spine is the sharpest and hardest part of many plants, which contains highly aligned fiber cells. Here, we report the micro- structures and mechanical properties as well as their correlation of single spine fiber cel...Spine is the sharpest and hardest part of many plants, which contains highly aligned fiber cells. Here, we report the micro- structures and mechanical properties as well as their correlation of single spine fiber cells （SFCs） from the cactus Echinocactus grusonii. It is found that the SFCs are 0.32-0.57 mm in length and 4.6-6.0 gm in width, yielding an aspect ratio of 53-124. X-ray diffraction and Fourier transform infrared spectrophotometry show that the spine fiber is mainly made up of cellulose I with a crystallinity index up to -76%. Nanoindentation tests show that a natural spine presents a high modulus of -17 GPa. Removing hemicellulose and lignin from the SFC significantly reduces its modulus to -0.487 GPa, demonstrating the critical role of adhesives hemicellulose and lignin in affecting the mechanical properties of the SFCs. This finding sheds light on de- signing novel bio-inspired high-performance composite nanomaterials with aligned nanofibers, such as using hemicellulose and lignin as adhesive in making carbon nanotube fibers.展开更多
文摘Solid lipid microparticles of erythromycin ethyl succinate were prepared using solvent evaporation method to improve its bioavailability and efficacy. The solvent was allowed to evaporate after which the various entrapments were determined; the best entrapment was used in the in vivo studies to determine the bioavailability and efficacy. This study was done with albino mice. The best entrapment obtained was 83% with a loading capacity of 2.9% （Batch D） and was used in comparison with the unformulated drug to check for the in vivo efficacy. The results show higher efficacy with the formulated drug than with the pure drug both in vitro and in vivo. The in vitro test results were better despite that some enzymes which need to act on the solid lipid microparticles were not present in the in vitro assay and could lead to a reduction in the release of the drugs. In conclusion, there was improvement in efficacy, and hence bioavailability.
文摘The aim of this work was to increase the efficacy of erythromycin ethyl succinate by encapsulation in beeswax lipid matrix using Myrj 52 as emulsifier. Different batches of SLM＇s （solid-lipid microparticles） were formulated and stable ones were selected. The encapsulation efficiency and loading capacities were calculated. The batch with the highest loading capacity was used for further assays. The particle size was determined by light microscopy. The sensitivity of different clinical bacterial isolates to erythromycin was tested using in vitro cultures and E. coli was selected for efficacy tests. The activity of the formulated drug was tested in the in vitro culture and compared to that of the unformulated drug. White albino mice were infected with E. coli and left for one day to develop significant bacteremia. They were then divided into 4 groups （n = 4） and treated with the formulation and unformulated drug at a dose of 7.14 mg/kg 8 hourly for 56 hours. A third group was given SLM＇s that do not contain drug, while another group was left untreated. The selected batch has an encapsulation efficiency of 94.83% with a loading capacity of 3.88%. The particle size was 17 ± 4 μm. At the end of the three day period of treatment, the group treated with unformulated erythromycin had much stooling anti weakness in the mice, and some deaths were recorded, while that treated with the formulation had 33.8% bacteremia and the clinical signs had largely subsided. The other two groups recorded deaths the following day after bacteremia induction. The results show marked improvement in efficacy of erythromycin ethyl succinate by formulation in SLMs with beeswax and lecithin as lipid matrix.
文摘Nanocapsule-based targeted delivery and stimulus-responsive release can increase drug effectiveness, while reducing the side effects of the drug. However, difficulties in the scale-up synthesis, fast burst release, and low degradability, could hamper the translation of drug nanocapsules from lab to clinic. Here we have controllably functionalized the biodegradable and widely available polysuccinimide, in order to obtain an amphiphilic poly（amino acid）. Using this polymer, we designed nanocapsules （〈 100 nm） for hydrophobic drug delivery, which could facilitate tumor targeting, hydrogen bond-based pH-responsive release, and real-time fluorescence tracking, in the second near-infrared region. This method is versatile, eco-friendly, and easy to scale up at low costs. In addition, this system can carry a cocktail of drugs, obtained by loading multiple anticancer drugs to the same vehicle. Our nanocapsules were observed to be stable in blood vessels （pH = 7.4）, and the pH-responsive release （pH = 5.0 in lysosome） was sustained. The chemotherapy results in tumor-xenografted mice suggested that our nanocapsule was safe and efficient, and may be a useful tool for drug delivery.
基金supported by the National Key Basic Research Program of China("973"program)(Grant Nos.2013CB932604,2012CB933403)the National Natural Science Foundation of China(Grant No.91023026)+2 种基金the Fundamental Research Funds for the Central Universities(Grant NosNP2013309,NS2012043)Jiangsu Planned Projects for Postdoctoral Research Funds(Grant No.1302015B)the NUAA Research Initiative for New Stuff(Grant No.1011-YAH13042)
文摘Spine is the sharpest and hardest part of many plants, which contains highly aligned fiber cells. Here, we report the micro- structures and mechanical properties as well as their correlation of single spine fiber cells （SFCs） from the cactus Echinocactus grusonii. It is found that the SFCs are 0.32-0.57 mm in length and 4.6-6.0 gm in width, yielding an aspect ratio of 53-124. X-ray diffraction and Fourier transform infrared spectrophotometry show that the spine fiber is mainly made up of cellulose I with a crystallinity index up to -76%. Nanoindentation tests show that a natural spine presents a high modulus of -17 GPa. Removing hemicellulose and lignin from the SFC significantly reduces its modulus to -0.487 GPa, demonstrating the critical role of adhesives hemicellulose and lignin in affecting the mechanical properties of the SFCs. This finding sheds light on de- signing novel bio-inspired high-performance composite nanomaterials with aligned nanofibers, such as using hemicellulose and lignin as adhesive in making carbon nanotube fibers.
