Interactions between bromophenol blue and cetyl- trimethylammonium bromide in aqueous solutions and microemulsions

Surfactants Accelerate Isotope Exchange-Based 18F-Fluorination in Water

Radiochemical yields (RCYs) of isotope exchange-based ¹⁸F-fluorination of non-carbon-centered substrates in water are rationally enhanced by adding surfactants, which increases both the rate constant k and local reactant concentrations. Among 12 surfactants, the cationic surfactant cetrimonium bromide (CTAB) and two nonionic surfactants (Tween 20 and Tween 80) were selected for their superior catalytic effects, namely, electrostatic effects or solubilization effects. For a model substrate, bis(4-methoxyphenyl)phosphinic fluoride, the ¹⁸F-fluorination rate constant (k) increased up to 7-fold, while its saturation concentration rose up to 15-fold due to micelle formation, encapsulating 70-94% of the substrate. With 30.0 mmol/L CTAB, the required ¹⁸F-labeling temperature of a typical organofluorosilicon prosthesis ([¹⁸F]SiFA) decreased from 95 °C to room temperature, achieving an RCY of 22%. For an E[c(RGDyK)]₂-derived peptide tracer with an organofluorophosphine prosthesis, the RCY in water at 90 °C achieved 25%, correspondingly increasing the molar activity (A_m). After high-performance liquid chromatography (HPLC) or solid-phase purification, the residual selected surfactant concentrations in the tracer injections were well below the FDA DII (Inactive Ingredient Database) limits or the LD50 in mice.

Development of bioflavonoid containing chemotherapeutic delivery systems for UV-damaged skin and kangri cancer

Background

The lower abdomen and inner thighs are most likely to become affected by kangri cancer because those areas are exposed to continuous exposure to kangri.

Objective

In this article, formulation and characterization of a water-in-oil microemulsion of 5-fluorouracil with rutin (R-5FU) for better skin penetration and inhibition of kangri cancer (skin cancer surfactant) is discussed.

Method

To produce R-5-FU microemulsions, surfactant-cosurfactant was mixed with oil. Distilled water was added dropwise with the help of a burette by gentle stirring at a constant temperature. The surfactant and co-surfactant were mixed into three particular ratios 1:1, 2:1, and 3:1. Further characterizations were performed, such as visual inspection and thermodynamic stability including a stress test and centrifugation. In visual inspection included assessment of the colour, homogeneity, and odour of the formulation of FU microemulsion.

Result

All three microemulsions, labeled RME1, RME2, and RME3, are highly stable. An oval shape of surface morphology of 5-FU was noticed by using a TEM image. The viscosity of RME3 was found to be 17.25±0.22 pa-s. The average globule size was 100–300 nm for all three RME. The results of human cadaver skin permeability are almost of the same pattern, butRME3 indicates the best skin permeability with negligible side effects on the skin.

Conclusion

The quantity of 5-FU released from all formulations at 3-hr ranged from 95.57% to 83.67%. None of the three formulations resulted in skin irritation, with irritancy score of zero (IS=0). Observation revealed no lysis, hemorrhage, or coagulation after application.