Adapalene-loaded poly(ε-caprolactone) microparticles: Physicochemical characterization and in vitro penetration by photoacoustic spectroscopy

Abstract

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.

Recent Advances Regarding the Therapeutic Potential of Adapalene

“…New microemulsions containing natural alkyl polyglucosides (as “green” surfactants) were developed in order to release intradermal ADP [ 126 ]. In addition, microparticles of poly(ε-caprolactone) loaded with ADP (10% and 20%) is another recently developed formulation [ 127 ]. Poly-ε-caprolactone nanospheres containing ADP were embedded successfully in a hyaluronate gel according to the ex vivo (on human skin for retention in the epidermis and dermis), in vitro (on human dermal fibroblasts for skin irritation), and in vivo studies (on rabbits for tolerability) [ 128 ].…”

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“…Preformulation Studies: 5 (a) Compatibility Studies:  DSC (Differential Scanning Calorimetry): 2,6 To check the purity of the drug and compatibility between the drug and excipients, DSC were carried out.…”

Development and Characterization of Precirol Ato 88 Base in Nanostructured Lipid Carriers (Nlc) Formulation With the Probe Sonication Method

“…The sample is heated from 20-400 °C with a heating speed of 10 °C/minute. Adapalene has crystalline properties, with a high melting point at 326 °C which indicates the amount of heat energy needed to be able to influence the system inside [29]. Precirol® ATO5 formed a curve in the range of 20.5 °-83.3 °C with an endothermic peak at a temperature of 59.6 °C, the mixture between Adapalen and Precirol® ATO5 experienced a narrowing, ie in the range of 19.4 °-77.7 °C and had a peek at 62.4 °C.…”