Biophysical evaluation of aminoclay as an effective protectant for protein stabilization during freeze-drying and storage

Abstract

This study aimed to evaluate aminoclay (3-aminopropyl-functionalized magnesium phyllosilicate) as an effective protectant for the stabilization of protein formulation in freeze-drying. Bovine serum albumin (BSA), as a model protein, was freeze-dried with aminoclay at various concentrations, and the effects of aminoclay on the structural stability of proteins were compared with those of the conventional stabilizers. The structural characteristics of the protein were determined by size exclusion chromatography (SEC), circular dichroism (CD), and Fourier transform infrared (FTIR) spectroscopy. Furthermore, physicochemical and morphological characteristics were examined by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). XRPD and DSC patterns indicated that the glass transition temperature (Tg) of the amorphous formulation of aminoclay mixed with proteins was gradually elevated as the concentration of aminoclay increased. FTIR and CD spectral analysis suggested that the protein structure was well maintained with aminoclay during the freeze-drying process and 3 months of storage at 4°C and 40°C. Furthermore, aminoclay conferred the greatest protection against aggregation and retained the monomer content of BSA even at a high temperature. The morphological characteristics of lyophilized proteins were also well conserved during the storage with aminoclay. These results suggested that aminoclay may be useful as an alternative stabilizer for maintaining the structural stability of protein formulations.

Development of an M cell targeted nanocomposite system for effective oral protein delivery: preparation, in vitro and in vivo characterization

“…Furthermore, these results were confirmed by deconvoluted amide I region of FT-IR spectra and the secondary structure contents of insulin released from nanoparticles (Additional file 1 : Figure S2). This result suggests that the aminoclay-based core complex can serve as an effective support matrix to maintain the native structure of immobilized proteins [ 22 , 24 ].…”

“…Previous research has demonstrated that the formation of the drug-clay complex improved the water solubility and bioavailability of drugs [23]. Aminoclay has several advantages as a drug carrier, including (i) easy preparation of a nanocomplex via spontaneous co-assembly with a diverse range of drugs, (ii) an effective support matrix to maintain the native structure of immobilized proteins, (iii) a reversible effect on tight junction opening, and (iv) low cytotoxicity [23][24][25][26][27][28][29]. Han et al [28] demonstrated that aminoclay had little cytotoxicity at concentrations of up to 500 μg/mL and did not induce apoptosis at concentrations of up to 1000 μg/mL.…”

Establishment of an Experimental Procedure for Preparing Trial Serum Samples for the Specific Serodiagnosis of Toxocara canis for External Quality Assessment Schemes

“…Therefore, the long-term stability of the freeze-drying method might still be limited, especially at high temperatures. These problems could be minimized by choosing the optimal pH and remaining moisture content, and more importantly, by the addition of stabilizers that might prevent tissue freezing and cell destruction during the cooling processes [23].…”

Effect of Trehalose on the Physicochemical Properties of Freeze-Dried Powder of Royal Jelly of Northeastern Black Bee

“…However, some proteins could undergo structural changes during the VFD process. For instance, Song et al reported that the structure of bovine serum albumin changed during the VFD process [9]. A limited number of potentials for biopharmaceuticals might undergo inactivation, denaturation, and other reactions during the fabricating process [10].…”