Investigation of Levan-Derived Nanoparticles of Dolutegravir: A Promising Approach for the Delivery of Anti-HIV Drug as Milk Admixture.

Nanoparticles composed of Levan and Dolutegravir (DTG) have been successfully synthesized using a spray drying procedure specifically designed for milk/food admixture applications. Levan, obtained from the microorganism Bacillus subtilis, was thoroughly characterized using MALDI-TOF and solid-state NMR technique to confirm its properties. In the present study, this isolated Levan was utilized as a carrier for drug delivery applications. The optimized spray-dried nanoparticles exhibited a smooth surface morphology with particle sizes ranging from 195 to 329 nm. In the in-vitro drug release experiments conducted in water media, the spray-dried nanoparticles showed 100 % release, whereas the unprocessed drug exhibited only 50 % release at the end of 24 h. Notably, the drug release in milk was comparable to that in plain media, indicating the compatibility. The improved dissolution rate observed for the nanoparticles could be attributed to the solid-state conversion (confirmed by XRD analysis) of DTG from its crystalline to amorphous state. The stability of the drug was verified using Fourier Transform Infra-Red Spectroscopy and Thermogravimetry-Differential Scanning Calorimetry analysis. To evaluate the in-vitro cellular toxicity, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was conducted, which revealed the CC50 value of 88.88 ± 5.10 µg/mL for unprocessed DTG and 101.08 ± 37.37 µg/mL for DTG nanoparticles. These results indicated that the toxicity of the nanoparticles was comparable to the unprocessed drug. Furthermore, the anti-HIV activity of the nanoparticles in human cell lines was found to be similar to that of the pure drug, emphasizing the therapeutic efficacy of DTG in combating HIV.

Production and characterization of microbial levan using sugarcane (Saccharum spp.) juice and chicken feather peptone as a low-cost alternate medium.

An alternate medium consisting of sugarcane juice (SJ) (Saccharum spp.) and chicken feather peptone (CFP) was employed for microbial synthesis of levan. SJ has considerable amounts of vital minerals, vitamins, and amino acids in addition to its major constituent, sucrose. Meanwhile, CFP is also a rich source of essential nutrients such as amino acids, micro and macro elements. Amino acids present in SJ and CFP, such as glutamic acid, arginine, aspartic acid, asparagine and elements such as Ca, Mg favoured the cell growth and levan production. In this present work, levan was produced using Bacillus subtilis MTCC 441 in five different media, namely, sucrose along with defined nutrients (M1), Sugarcane Juice without nutrients (M2), SJ with defined nutrients (M3), SJ along with chicken feather peptone (M4) and sucrose without nutrient (M5). Alternative nutrient medium using SJ and CFP (M4) showed a promising levan yield of 0.32 ± 0.01 g of levan/g of sucrose consumed, which is 64% of the theoretical levan yield possible. Levan produced was characterized using Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). There is a change in low molecular weight fractions of levan obtained from SJ and CFP medium compared to the defined medium. Produced levan from the composite medium exhibited strong antioxidant activity and was biocompatible when tested against endothelial cells. The substrate cost was 20% lower than the cost of defined medium. Thus, a composite medium made of SJ and CFP can serve as an alternate low-cost medium for microbial fermentation.

Levan production from sucrose using chicken feather peptone as a low cost supplemental nutrient source.

Chicken feather peptone (CFP) derived from poultry waste is a rich source of essential minerals and amino acids. This, along with suitable carbon source, can be used as a low cost complex supplemental nutrient source for microbial fermentation. In the present work, CFP blended with sucrose was evaluated for the production of levan using Bacillus subtilis MTCC 441. Amount of CFP added to the medium significantly influenced levan production and it was found that at a concentration 2 g/L, maximum levan yield of 0.26 ±â€¯0.04 g/g sucrose was obtained. The levan yield obtained with CFP as a low cost supplemental nutrient source was comparable with that obtained from commercial medium (0.31 ±â€¯0.02 g/g sucrose). Levan produced using CFP was tested on primary cell lines at various concentrations (100-1000 µM) and found to be non-toxic and bio-compatible in nature. This indicates that CFP could be used as low cost nutrient source for levan production.

Studies on solvent precipitation of levan synthesized using Bacillus subtilis MTCC 441.

Levan is a water soluble biopolymer widely used in food, pharma, personal care and aquaculture industries. In this work, levan was synthesized by Bacillus subtilis MTCC 441 using sucrose as a sole carbon source. Effects of pH, sucrose concentration, nitrogen source, nitrogen concentration, inoculum size and agitation speed on levan production were studied. Yeast extract (YE) was found to be the best nitrogen source. Sucrose concentration - 100 g/L, pH - 7, YE concentration - 2 g/L, inoculum size 10% (v/v) and RPM - 150 were found to be optimal values for levan production. Effects of precipitation pH (3-12), choice of solvent (ethanol, isopropanol, acetone, and methanol) and supernatant to solvent ratio (1:1 to 1:6) on levan yield were also studied. Isopropanol resulted in maximum levan recovery among the four solvents considered. Optimal pH and supernatant to solvent ratio for levan precipitation were found to be 11 and 1:5, respectively. Corresponding levan yield was 0.395 g/g of sucrose supplied. The product obtained was characterized using FTIR, 1H-NMR, 13C-NMR, and GPC. The cytotoxicity of the precipitated levan was studied on EA.hy926 cell line using MTT assay and the compound was proven to be non-toxic to the cells.