Pulsatile Controlled Release and Stability Evaluation of Polymeric Particles Containing Piper nigrum Essential Oil and Preservatives

Abstract

Considerable efforts have been spent on environmentally friendly particles for the encapsulation of essential oils. Polymeric particles were developed to encapsulate the essential oil from Piper nigrum based on gelatin and poly–ε–caprolactone (PCL) carriers. Gas Chromatography ((Flame Ionization Detection (GC/FID) and Mass Spectrometry (GC/MS)), Atomic Force Microscopy (AFM), Nanoparticle Tracking Analysis (NTA), Confocal Laser Scanning Microscopy (CLSM), Attenuated Total Reflectance–Fourier-transform Infrared Spectroscopy (ATR–FTIR), and Ultraviolet–Visible (UV–VIS) spectroscopy were used for the full colloidal system characterization. The essential oil was mainly composed of β-caryophyllene (~35%). The stability of the encapsulated systems was evaluated by Encapsulation Efficiency (EE%), electrical conductivity, turbidity, pH, and organoleptic properties (color and odor) after adding different preservatives. The mixture of phenoxyethanol/isotialzoni-3-one (PNE system) resulted in enhanced stability of approximately 120 and 210 days under constant handling and shelf-life tests, respectively. The developed polymeric system presented a similar controlled release in acidic, neutral, or basic pH, and the release curves suggested a pulsatile release mechanism due to a complexation of essential oil in the PCL matrix. Our results showed that the developed system has potential as an alternative stable product and as a controlling agent, due to the pronounced bioactivity of the encapsulated essential oil.

Biodefensive Based on Piper nigrum Essential Oil for Controlling of Anopheles aquasalis Larvae: Influence of Temperature (35 °C) and Preservatives

“…The high initial EE% showed the success of the developed loaded particles. However, the evaluation of the EE% is not a single parameter to guarantee the stability of the formulation over time [ 18 , 21 ].…”

“…Gelatin/PCL-based particles loaded with P. nigrum essential oil were synthesized according to previous report [ 9 , 21 ] with modifications. The same methodology was performed without essential oil (in solution II) to obtain the colloidal system containing unloaded particles.…”

“…Different preservatives were considered to verify their influence on the formulation stability. High Encapsulation Efficiency (EE%) is not a single parameter to guarantee the formulation stability over time [ 18 , 21 , 22 ]. The use of preservatives in colloidal systems is an effective alternative to increase their shelf-life [ 23 ], especially by delaying the exposure of bioactive compounds into the medium as a result of the particles destabilization/rupture [ 21 ].…”

“…High Encapsulation Efficiency (EE%) is not a single parameter to guarantee the formulation stability over time [ 18 , 21 , 22 ]. The use of preservatives in colloidal systems is an effective alternative to increase their shelf-life [ 23 ], especially by delaying the exposure of bioactive compounds into the medium as a result of the particles destabilization/rupture [ 21 ]. For this reason, several parameters are simultaneously correlated to the stability of colloidal systems, such as pH, electrical conductivity, EE% and turbidity [ 18 ].…”

“…For this reason, several parameters are simultaneously correlated to the stability of colloidal systems, such as pH, electrical conductivity, EE% and turbidity [ 18 ]. The biodegradability of gelatin/PCL-based particles in colloidal systems is a natural process, so the development of preservative-containing formulation allows the increase of their shelf-life [ 21 , 23 ].…”