Human Hair Keratin Microspheres Prepared by the Water-In-Oil Emulsion Solvent Diffusion Method for Hydrophilic Drug Carrier

Introduction

In recent years, keratin-based materials have been used in many applications¹ because of their environmental and safety relative to synthetic materials. The main sources of keratin are epithelial cells,² human hair, quills, wool, horns, hooves and nails of animals as well as feathers, claws and beaks of birds and reptiles.¹ Moreover, previous reports have demonstrated that the keratin protein possesses unique characteristics of bioactivity when properly applied in biomedical and pharmaceutical applications,^3,4 water purification, textile finishing and composite materials.⁵ Drug-loaded materials been attached onto structural proteins such as silk fibroin^6,7 and keratin^8,9 according their high drug loading efficiency and stability. Microspheres are very interesting for drug delivery applications as their shape is suitable to allow movement in blood vessels. The drug carrier is known as a key factor supporting distribution, solubility and stability especially for water-soluble drugs.⁷ Microspheres can be constructed by different techniques included emulsion solvent extraction/evaporation, emulsion core template extraction, spray drying and electro spraying,¹⁰ emulsion, phase separation, precipitation and gelation.^11-16 There are some limitations with the delivery of water-soluble drugs or biological molecules such as enzymes or proteins due to their sensitivity to metabolic processes in the body as well as physical-chemical treatments both during processing or post treatment. Many reports have proposed encapsulation of biological molecules.^17-19

Herein, the authors present an emulsion solvent diffusion method for human keratin microspheres preparation with and without blue-dextran, a sample hydrophilic drug entrapment. The suitable conditions concerning microspheres processing were investigated andwere discussed. In addition, drug release profile from the HK microspheres was determined in vitro.

Materials and Method

Human hair was collected, washed and dried in room temperature. Hair was immersed in n-hexane for 12 h to remove some lipids. Keratin from human hair was extracted following the method of Shindai.²⁰ The hair sample was mixed with a solution of 8 M urea, 0.26 M SDS, 0.4 M NaOH in 100 mL distilled water at 70°C and stirred until the hair was dissolved. The solution was then dialyzed for 3 days in distilled water using cellulose tubular membranes (molecular weight cut-off 3.5 kDa, Thermo Scientific, USA). Finally, the human keratin (HK) solution was checked by evaporation technique and the...