Assessing compatibility of excipients selected for a sustained release formulation of bilberry leaf extract

Abstract The study is aimed to assess the compatibility of bilberry leaf powder extract (BLPE) with six excipients selected for sustained-release (SR) tablet formulation. The BLPE was obtained with the addition of L-arginine and Myo-inositol as the carriers. Thermogravimetric (TG-DTG) analysis and Fourier-transform infrared spectroscopy (FTIR), supported by Pearson correlation analysis, were applied to detect possible interactions in the binary mixtures (1:1) of the BLPE with each excipient. The TG-DTG showed some deviations in the thermal behavior of the BLPE / excipient mixtures. However, only the thermal behavior of magnesium stearate in the mixture significantly differed from individual samples, which suggested chemical interaction for this excipient. The FTIR analysis confirmed that the BLPE is compatible with Eudragit L100, Methocel K4M, Methocel K100LV, Avicel PH-101, and Plasdone S-630. Whereas it undergoes solid-state chemical interaction in the binary mixture with magnesium stearate. According to the FTIR-spectra, it is suggested that this interaction results in the formation of stearic acid and alkalization of the medium. These findings evidence for the possibility of using TG-DTG analysis as an independent thermal technique for compatibility studies and also confirm the earlier reported interaction of basic lubricants, e.g., stearic salts, with active ingredients containing amino groups.

Evaluation of anti-obesity and lipid-lowering properties of Vaccinium myrtillus leaves powder extract in a hamster model.

Background Vaccinium myrtillus leaves are known to be rich in phenols and have been used in traditional medicine as an antidiabetic remedy. This study evaluated the powder extract of V. myrtillus leaves obtained with the use of L-arginine and myo-inositol for anti-obesity and lipid-lowering potential in hamsters. Methods Standard phytochemical methods were used to determine the total phenolic and total flavonoid contents of the extract. The obesity condition was induced in Syrian hamsters by feeding them with highly palatable fat- and sugar-rich diet (40.3 kcal% fat) for 12 weeks. From the 10th week of diet feeding, the obese hamsters were treated with the powder extract of V. myrtillus leaves (15, 25 and 35 mg/kg/day, respectively) and "Styfimol" (6.2 mg/kg/day of hydroxycitric acid) as a positive control drug. At the end of the treatment period, the biochemical parameters as well as visceral fat mass were determined. Results Vaccinium myrtillus leaves powder extract at 25 and 35 mg/kg/day caused a significant reduction in body weight gain and visceral fat mass in obese hamsters. Serum triacylglycerols, free fatty acids, total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels were also significantly lower. Besides, the hamsters treated with powder extract at 25 and 35 mg/kg/day had the closest intact value ratio of high-density lipoprotein cholesterol and LDL-C compared with positive control animals. Conclusions The results showed that V. myrtillus leaves powder extract is a promising therapeutic agent for the treatment of obesity and obesity-induced diseases.