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Microsphere Preparation Technologies

Microspheres are spherical particles of nanometer and micron size, which are used in a wide range of applications such as disease diagnosis and drug delivery due to their specific size, structure and properties. Especially in the biopharmaceutical field, microspheres can reduce the toxic side effects of drugs, increase the effectiveness of drugs and improve the quality of drugs as a carrier for slow and controlled drug release. CD Formulation focuses on the key technology of microsphere preparation, breaks through the structure control and precise preparation of microsphere materials, establishes a high-performance preparation platform, and provides customers with high-quality products and technical services.

Schematic diagram of microsphere preparation.Fig.1 Schematic diagram of microsphere preparation. (HAN et al., 2018)

Materials for Microspheres

The materials used to make microspheres can be divided into two categories: natural biomaterials and synthetic polymers. Natural biomaterials mainly include chitosan, collagen, starch, liposomes, lipoproteins, etc. Chitosan, collagen and starch are matrix components of tissues with good biocompatibility and biodegradability, low cytotoxicity, and degradation products can be completely absorbed by the body. And synthetic polymer materials mainly include PEG, (lactic acid-hydroxyacetic acid) polymer (PLGA) and polyvinyl alcohol (PVA), which are well used in drug transportation.

Microsphere Preparation Technology

Microfluidic technology is a method of producing droplets through microchannels, using volume or pressure to drive the immiscible continuous phase and the dispersed phase to flow in their respective channels, and the two phases meet at the intersection of the channels, and the continuous phase is squeezed or sheared against the dispersed phase to induce interfacial instability and fracture to produce dispersed droplets.

Membrane emulsification technology works on the principle that the dispersed phase passes through the membrane pores of a microporous membrane under an applied pressure and forms droplets on the membrane surface. When the droplets reach a certain diameter under the flushing action of the continuous phase flowing along the membrane surface, they peel off from the membrane surface and form an emulsion. This is a method to achieve monodispersity of emulsion droplets by controlling the dispersion pressure and membrane pore size in order to prepare uniform particle size microspheres.

The solvent volatilization method is a widely used method for the preparation of microspheres, which can be prepared in industrial production process by using reactor and static mixer.

The principle of phase separation is to add a third component, usually an organic non-solvent, to the polymer-drug-solvent system under stirring, and the solubility of the polymer decreases with the addition of the third component, so that at a specific point in the two phases, the solvent separates from the polymer to form a very soft drug-carrying droplet. The system is then transferred to another organic non-solvent and the microspheres are cured to give the final microspheres.

Spray Drying technology is a method of preparing microspheres by spraying a liquid excipient into a hot drying medium and converting the excipient into a dry powder in a spray dryer. The specific preparation process can be divided into three steps: the atomizer atomizes the raw material solution into small droplets; the drying gas cures and dries the small droplets; and the dry particles are separated from the drying medium.

The hot melt extrusion method is used to prepare microspheres, i.e. taking the prescribed amount of drug and excipients, putting them into the hot melt extrusion apparatus, setting the hot melt temperature, heating the mixture and melting it, then extruding it through the sieve plate and cooling it rapidly to form a solid strip, and then crushing it to make microspheres.

If you are interested in our technology, please feel free to contact us.


  1. Xian-Wei, H. A. N., et al. (2018) Preparation of poly (vinyl alcohol) microspheres based on droplet microfluidic technology. Chinese Journal of Analytical Chemistry, 46(8), 1269-1274.
Please note: Our products and services are not intended to be used directly in diagnostic or therapeutic procedures.
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