Adapalene (ADAP) is an important drug widely used in the topical treatment of acne. It is a third-generation retinoid and provides keratolytic, anti-inflammatory, and antiseborrhoic action. However, some topical adverse effects such as erythema, dryness, and scaling have been reported with its commercial formula. In this sense, the microencapsulation of this drug using polyesters can circumvent its topical side effects and can lead to the enhancement of drug delivery into sebaceous glands. The goal of this work was to obtain ADAP-loaded poly(ε-caprolactone) (PCL) microparticles prepared by a simple emulsion/solvent evaporation method. Formulations containing 10 and 20% of ADAP were successfully obtained and characterized by morphological, spectroscopic, and thermal studies. Microparticles presented encapsulation efficiency of ADAP above 98% and showed a smooth surface and spherical shape. Fourier transform infrared spectroscopy (FTIR) results presented no drug-polymer chemical bond, and a differential scanning calorimetry (DSC) technique showed a partial amorphization of the drug. ADAP permeation in the Strat-M membrane for transdermal diffusion testing was evaluated by photoacoustic spectroscopy (PAS) in the spectral region between 225 and 400 nm after 15 min and 3 h from the application of ADAP-loaded PCL formulations. PAS was successfully used for investigating the penetration of polymeric microparticles. In addition, microencapsulation decreased the in vitro transmembrane diffusion of ADAP.

No abstract

Background: Tacrolimus (TAC) is a drug of natural origin used in conventional topical dosage forms to control atopic dermatitis. However, direct application of the drug often causes adverse side effects in some patients. Hence, drug nanoencapsulation could be used as an improved novel therapy to mitigate the adverse effects and enhance bioavailability of the drug. Methods: Physicochemical properties, in vitro drug release experiments, and in vivo anti-inflammatory activity studies were performed. Results: TAC-loaded nanocapsules were successfully prepared by the interfacial deposition of preformed polymer using poly(ε-caprolactone) (PCL). The nanoparticulate systems presented a spherical shape with a smooth and regular surface, adequate diameter (226 to 250 nm), polydispersity index below 0.3, and suitable electrical stability (−38 to −42 mV). X-ray diffraction confirmed that the encapsulation method provided mainly the drug molecular dispersion in the nanocapsule oily core. Fourier-transform infrared spectra suggested that nanoencapsulation did not result in chemical bonds between drug and polymer. In vitro drug dissolution experiments showed a controlled release with a slight initial burst. The release kinetics showed zero-order kinetics. As per the Korsmeyer–Peppas model, anomalous transport features were observed. TAC-loaded PCL nanocapsules exhibited excellent anti-inflammatory activity when compared to the free drug. Conclusions: TAC-loaded PCL nanocapsules can be suitably used as a novel nano-based dosage form to control atopic dermatitis.

No abstract

A simple and fast analytical method of ultra-high performance liquid chromatography (UHPLC) was developed and validated in order to assay isradipine in poly(ε-caprolactone) (PCL)/polyethylene glycol (PEG) nanocapsules. Experiments were performed by UHPLC on a C18 chromatographic column at 25°C using a mobile phase composed by methanol and water (85:15 v/v) with a flow rate of 0.5 mL.min−1 and UV detection at 327nm for achieving a total run time of 1.5 min. The UHPLC method was validated according to the guidelines set on The International Conference on Harmonisation. It proved to be selective, linear (r = 0.99962), precise (RSD < 4.1%), and accurate (recovery rates between 95.24 and 96.53%) at the range from 10 to 40 µg.mL−1. The performance was robust when slight changes in the flow rate, wavelength of detection, and mobile phase composition were tested. It was successfully applied to quantify isradipine from nanoparticulate polymeric systems, showing high loading efficiency rates, greater than 98.55%. These results provided an experimental basis to use this method for quantifying isradipine with reliable results, besides being very fast, easy to perform and cheaper.