Reverse Micelle-Based Microencapsulation of Oxytetracycline Hydrochloride into Poly-d,l-Lactide-co-Glycolide Microspheres

Abstract

The objectives of this study were to solubilize oxytetracycline hydrochloride (HCl) in reverse micelles to prepare poly-d,l-lactide-co-glycolide (PLGA) microspheres and to explore parameters affecting its encapsulation efficiency. Oxytetracycline HCl was dissolved in the reverse micelles consisting of cetyltrimethylammonium bromide, water, and ethyl formate. A PLGA polymer was then dissolved in the reverse micellar solution, and a modified solvent quenching procedure was carried out to prepare PLGA microspheres. Encapsulation efficiencies of oxytetracycline HCl ranged from 2.3 +/- 0.2 to 24.9 +/- 4.6%, depending on experimental conditions. Important parameters affecting its encapsulation efficiency included the amounts of water used to prepare the reverse micelles and PLGA polymer. With regard to microsphere morphology, the reverse micellar process produced the microspheres with smooth and pore-free surfaces. In particular, their internal matrices did not possess hollow cavities that were frequently observed when a typical double emulsion technique was used to make microspheres. In summary, it was possible to encapsulate oxytetracycline HCl into PLGA microspheres via the ethyl formate-based reverse micellar technique. We also anticipate that the use of ethyl formate could avoid environmental and human toxicity issues associated with methylene chloride.

Microstructures of encapsulates and their relations with encapsulation efficiency and controlled release of bioactive constituents: A review

“…They are formed from monolayer of single or multiple surfactants. Surfactants used for micelle and reverse micelle production can be, for example, lecithin, monoglycerides and phosphatidylcholine (Kim et al., 2007; McClements, 2017; Singh, Yadav, Pandey, Gupta, & Singh, 2019; Sun & Bandara, 2019). Micelle and reverse micelle can encapsulate only one type of hydrophobic and hydrophilic core materials, respectively (Singh, Thompson, & Corredig, 2012).…”

“…On the other hand, reverse micelle has noted to exhibit lower encapsulation efficiency for hydrophilic cores having molecular weight lower than 500 Da. Low encapsulation efficiency, for example, was noted for tetracycline hydrochloride (5%) and oxytetracycline hydrochloride (24.9%) encapsulated in a reverse micelle prepared from poly-d,l-lactide-co-glycolide (PLGA) in conventional methylene chloride-based emulsion and in ethyl formate solution containing cetyltrimethylammonium bromide, respectively (Kim et al, 2005(Kim et al, , 2007. Note that PLGA is a well-known encapsulant used for drug delivery that can control the release of encapsulated drugs (Kim et al, 2005(Kim et al, , 2007.…”

Recent Trends in Preparation of Poly(lactide‐co‐glycolide) Nanoparticles by Mixing Polymeric Organic Solution with Antisolvent

“…All HIP-hybridized o/w nanoencapsulation techniques described above proceed with dissolving hydrophobic ion complexes in a dispersed organic solvent. Instead, Kim et al proposed a reverse micelle-based o/w emulsion solvent evaporation/extraction method [119]. In their work, oxytetracycline HCl was directly dissolved in the reverse micelles consisting of cetyltrimethylammonium bromide, water, and ethyl formate.…”

Microencapsulation as a Noble Technique for the Application of Bioactive Compounds in the Food Industry: A Comprehensive Review

“…Reverse micelle exhibited lower encapsulation efficiency for hydrophilic core materials such as tetracycline encapsulated in PLGA (poly-d, L-lactide-co-glycolide) in methylene chloride added to cetyltrimethylammonium bromide. This lower encapsulation efficiency in reverse micelle is attributed to small hollow cavities, the presence of several pores on the surface, as well as the lower molecular weight of the core material [160]. The hydrophilic core material with a molecular weight of more than 500 Da exhibited higher encapsulation efficiency (98%) during the reverse micelle method of encapsulation [161].…”