4 Veronesi U, Saccozzi R, Vecchio DM. Comparing radical mastectomy with quadrantectomy, axillary dissection, and radiotherapy in patients with small cancers of the breast. N EnglJ Med 1981;305:6-11. 5 Tagart REB. Partial mastectomy for breast cancer.
In our study, we aimed to validate a method based on liquid chromatography-mass spectrometry (LC-MS) to quantify spironolactone (SPI) and its active metabolite canrenone (CAN) simultaneously in plasma samples to support in vivo experiments. Compounds were separated by using a C 18 column with the isocratic elution of a mobile phase composed of 0.1% (v/v) formic acid in methanol-water (60:40 v/v) at a flow rate of 0.4 mL min −1 . SPI and CAN were detected in an electrospray interface operating in a positive ionization mode and quantified using the selective ion mode monitoring of mass-charge ratios (m/z) of 439.0 for SPI and 363.1 for CAN. After calculating the matrix effect using theoretical equations, we observed the strong interference of plasma in the equipment-generated signal, which required creating analytical curves using the matrix as a solvent. The method was nevertheless linear (r 2 > 0.999) in a concentration range of 0.4-5.0 μg mL −1 , as well as precise, with a coefficient of variation less than 5%. SPI's and CAN's recovery rates from the plasma ranged from 87.4% to 112.1%, while their limits of detection (i.e., 0.07 µg mL −1 and 0.03 µg mL −1 , respectively) and quantification (i.e., 0.20 µg mL −1 and 0.08 µg mL −1 , respectively) in the presence of plasma contaminants were low. Therefore, the bioanalytical method seems to be feasible for quantifying SPI and CAN in plasma.
Background:
α-Bisabolol (BIS) is a sesquiterpene extracted from chamomile flowers, which has been used to topically treat burnt skin has been reported. High lipophilicity of BIS, however, is a problem for both skin application and washing.
Objective:
The present study aimed to prepare and characterize a stable and safe aqueous-based nanoemulsion to incorporate BIS and favor skin penetration focusing on skin burns' topical treatment.
Method:
Oil-in-water nanoemulsions were obtained from a pseudo-ternary phase diagram. The selected nanoemulsion was characterized (droplet size, PDI, and zeta potential), and the stability was assessed for 60 days at 6ºC and room temperature. The irritability of the formulation was determined by HET-CAM. Skin permeation studies were carried out in vitro intact skin, hot water burn skin, and hot plate burn skin.
Results:
The nanoemulsion incorporated 1% (w/w) BIS, presented droplets' size of 14.0±0.8 nm (PDI= 0.13±0.02), the zeta potential of +7.5±1.9 mV, and was physically stable over 60 days. The HET-CAM did not show any irritability process provided by the nanoformulation. In the skin permeation experiments, when compared to an oily control solution of BIS, nanoemulsion increased 3.7-fold penetration of the drug in intact skin, likely because the nanoformulation acted as an absorption drug enhancer. On a hot water burn skin model, the increase in drug penetration was 1.7-fold, and in the hot plate burn skin, it was 2.3-fold.
Conclusion:
The nanoemulsion seems to be a promising alternative for skin burns' topical treatment using this natural active substance.
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