Preparation, characterization, and in vitro release studies of insulin-loaded double-walled poly(lactide-co-glycolide) microspheres

Abstract

The purpose of this study was to fabricate insulin-loaded double-walled and single-polymer poly(lactide-co-glycolide) (PLGA) microspheres using a fast degrading glucose core, hydroxyl-terminated poly(lactide-co-glycolide) (Glu-PLGA), and a moderate degrading carboxyl-terminated PLGA polymers. A modified water-in-oil-in-oil-in-water (w/o/o/w) emulsion solvent evaporation technique was employed to prepare double-walled microspheres, whereas single-polymer microspheres were fabricated by a conventional water-in-oil-in-water (w/o/w) emulsion solvent evaporation method. The effect of fabrication techniques and polymer characteristics on microspheres size, morphology, encapsulation efficiency, in vitro release, and insulin stability was evaluated. The prepared double-walled microspheres were essentially non-porous, smooth surfaced, and spherical in shape, whereas single-polymer microspheres were highly porous. Double-walled microspheres exhibited a significantly reduced initial burst followed by sustained and almost complete release of insulin compared to single-polymer microspheres. Initial burst release was further suppressed from double-walled microspheres when the mass ratio of the component polymers was increased. In conclusion, double-walled microspheres made of Glu-PLGA and PLGA can be a potential delivery system of therapeutic insulin.

Preparation, in vitro release and antibacterial activity evaluation of rifampicin and moxifloxacin-loaded poly(D,L-lactide-co-glycolide) microspheres

“…homogenization (W1/O/W2). Then, the emulsion is then stirred to volatilize the organic solvent; subsequently, the carrier polymer gradually solidifies to form microspheres encapsulating the drug [31]. Nevertheless, previous studies have not suggested that hydrophobic and hydrophilic drugs can improve the encapsulation rate of hydrophilic drugs when they are loaded together by the technique [32].…”

Preparation, Characterization and Antifungal Activity Studies of AgNPs Loaded Silk Fibroin Hydrogels

“…Standard calibration curve of colloidal Ag nanoparticles solution was used for AgNPs quantification in the hydrogels. Encapsulation efficiency was determined by the following equation [4]. All the measurements were performed in triplicate.…”

“…Several applications in pharmaceutical and medical technology are based on dispersions of particles in a fluid or gel phase [2]. In the last three decades, micro and nanoparticles based polymeric systems have been widely explored for controlled and targeted delivery of drugs and antigens in variety of forms (films, gels, capsules, tablets and creams) mainly due to their ability to sustained drug release for long periods of time, enhanced target, low toxicity, easy manipulation/administration [3][4][5][6]. The release properties, the load-bearing capacity, the porosity, and the cell-matrix interactions should be considered for the development of a material to be used in controlled drug delivery and also as scaffolds for tissue engineering [7][8][9] Also, the possibility to adjust the release profile of a polymeric system is important to achieve the therapeutic concentration of the drug [1].…”

Controlled Release of Lysozyme from Double-Walled Poly(Lactide-Co-Glycolide) (PLGA) Microspheres

“…A previously developed water-in-oil-in-oil-in-water (w 1 /o/o/w 2 ) emulsion solvent evaporation method was modified and employed to fabricate lysozyme encapsulated in double-walled microspheres [23]. A detailed method of preparation can be found in our previous publications [26,27]. Briefly, PLGA was dissolved in ethyl acetate (EA) and emulsified with an aqueous solution of lysozyme using a basic homogenizer of IKA ® T 10 (Werke GmbH and Co., Staufen, Germany).…”

“…In this study, different solubilities of Glu-PLGA and PLGA in ethyl acetate were used to recognize the core and shell polymer layer. A detailed method can be found in the previous articles [26,27].…”