Enteric-coated insulin microparticles delivered by lipopeptides of iturin and surfactin

Abstract

Surfactin, a lipopeptide produced by Bacillus species, has been used for the oral delivery of insulin. In this study, another lipopeptide of iturin was tested for its ability to orally delivery insulin alone or plus surfactin. Iturin could form co-precipitate with insulin at acidic pH values. After treatment by ultrasonification, the structure of coprecipitate was destroyed that led to a significant decrease in hypoglycemic effect after oral administration. Iturin weakly binds to (Kd = 257 μM) and induce insulin structure more compact that is favorable for insulin uptake by the intestine. After being coated with Acryl-Eze by lyophilization, the coprecipitate formed the spherical enteric-coated insulin microparticles delivered by iturin with a relative oral bioavailability of 6.84% in diabetic mice. For further improving oral hypoglycemic effect, surfactin was added to form the spherical enteric-coated insulin microparticles in a formulation containing insulin, Acryl-Eze, iturin and surfactin at a ratio of 1:1:0.5: 0.5 (w/w), with an insulin encapsulation efficiency of 66.22%. The enteric-coated insulin microparticles delivered by iturin plus surfactin showed a classical profile for controlled release in the intestine with a relative bioavailability of 7.67% after oral administration, which could effectively control the postprandial blood glucose at a level about 50% of the initial one just like the subcutaneous injection. Collectively, iturin plus surfactin is more efficient for oral delivering insulin than the sole one, and the resultant enteric-coated insulin microparticles are potential for the development of oral insulin to control postprandial blood glucose in diabetic patients.

Preparation and Characterization of a Novel Aqueous Dispersion for Enteric Coating of Pantoprazole Sodium Pellets

“…It is necessary to add a plasticizer to the dispersion during the MIN HAN 1,2 QIN YU 1 XUERONG LIU 1 FUQIANG HU 1, * HONG YUAN 1, * coating process (4). Mechanisms of film formation of aqueous dispersions and organic solutions are different (5)(6)(7)(8). With evaporation of the solvent, polymers in the organic solution condense and polymer chains interdiffuse, resulting in alteration from a solution to a gel and finally a film (9).…”

Systemically engineering Bacillus amyloliquefaciens for increasing its antifungal activity and green antifungal lipopeptides production

“…Briefly, 200 ml broth supernatant was adjusted to pH 2.0 with 6 M HCl for precipitating lipopeptides, then the precipitates were dissolved in 20 ml pure water and extracted by the same volume of n -butanol. The extracted substances were loaded into silica gel (FCP-200) column then eluted by n -butanol: ethanol: acetic acid: water = 30:70:5:20 (v/v) ( Xing et al, 2018 ). The eluted fractions with iturin and fengycin were monitored by measuring the absorbance at 210 nm wavelength and the antifungal activity against F. oxysporum .…”

An Overview of Microparticulate Drug Delivery System and its Extensive Therapeutic Applications in Diabetes

“…Nevertheless, these microparticles maintained the postprandial blood glucose level of about 50% of the initial dose, similar to the subcutaneous injection. 112 In addition, glucan microparticles thickened with thermosensitive poloxamer 407 gels were suggested to be potential insulin oral carriers. 113 The multilayer-coated microparticles using a layer-by-layer polymers installation was another assessed approach.…”