What are the advantages of PVA polymer properties in pharmaceutical applications?

1. Overview of PVA polymer

With the mutual penetration of polymer material science and modern pharmacy, the application of polymer materials as drug controlled release carriers has become one of the hottest research directions, among which PVA is the most important polymer compound in this regard. PVA polymer is usually prepared by alcoholysis of polyvinyl acetate in solvents such as methanol, ethanol or methyl acetate. The alcoholysis degree is 98%-100% for completely alcoholysed polyvinyl alcohol.

PVA polymer is a good film-forming and gelling material, widely used in gels, transdermal preparations, coatings, and films. It can also be used as a matrix for papuam. It is also an ideal suspending agent and thickener. It is a tablet adhesive and an important sustained-release and controlled-release skeleton material that non-toxic, tasteless, non-irritating to the skin, and does not cause skin allergies. It has attracted more and more attention. Let's explore what are the advantages of PVA polymer properties in pharmaceutical applications through this article.

2.PVA polymer properties

PVA has the characteristics of convenient synthesis, safety and low toxicity, easy control of product quality, low price, and easy use. Therefore, PVA is an excellent pharmaceutical excipient with potential for further development. PVA polymer properties are as follows.

Solubility

PVA is extremely hydrophilic and can be dissolved in hot or cold water. The higher the water temperature, the greater the solubility, but it is almost insoluble in organic solvents. In addition, the solubility of PVA is related to its relative molecular mass, alcoholysis degree and polymerization degree. Generally speaking, the larger the relative molecular mass, the stronger the crystallinity, the worse the water solubility, but the viscosity of the aqueous solution increases accordingly.

Usually, when it comes to the influence on the solubility of PVA, the alcoholysis degree is greater than the polymerization degree, and the water solubility of the alcoholysis degree between 87% and 89% is better. The higher the alcoholysis degree, the higher the temperature required for dissolution. In general, partially alcoholyzed and low-polymerized PVA dissolves very quickly, while completely alcoholyzed and high-polymerized PVA dissolves slowly. The dissolution process of PVA is carried out in stages, namely: affinity wetting-swelling-infinite swelling-dissolution.

Properties and miscibility of aqueous solutions

PVA aqueous solution is a non-Newtonian fluid. When the concentration of PVA increases, the viscosity of the solution rises sharply; when the temperature rises, the viscosity decreases. At the same time, PVA aqueous solution has a certain surface activity. General rule: the lower the alcoholysis degree, the more residual acetyl groups, the lower the surface tension, and the stronger the emulsification ability. PVA aqueous solution can be mixed with a variety of water-soluble polymers, and mixing with some polymers can form gels. For example, when borax or boric acid aqueous solution is mixed with PVA aqueous solution, irreversible gelation can occur.

Film-forming property

PVA has good film-forming property. Put a certain mass of PVA into deionized water, dissolve it at 90℃, cool it to room temperature, filter it, degas it, then add a certain concentration of glutaraldehyde aqueous solution and a certain equivalent concentration of sulfuric acid as a catalyst, stir it evenly, and form a film on a clean polytetrafluoroethylene plate after static degassing. Irradiate it with infrared light and crosslink it for a period of time. Finally, peel the film off the polytetrafluoroethylene plate, and after a short-term heat treatment at 170℃, a cross-linked polyvinyl alcohol film is obtained. The mechanical properties of the film are excellent, and the tensile strength of the film increases with the increase of polymerization degree and alcoholysis degree. In addition, the addition of glycerol, polyols, etc. can play a plasticizing role, thereby further improving the flexibility of the film. Polyvinyl alcohol film is a water-soluble film with excellent hygroscopicity and oxygen barrier properties (under dry conditions), and is also resistant to organic solvents and oils, and is biodegradable and does not pollute the environment.

3. In summary

PVA polymer properties are great in all aspects and can be used as an excipient for oral preparations, topical preparations, and transdermal preparations in pharmaceutical preparations. It can also be used to make capsule materials for microcapsules, film preparations, and film-forming materials for coating agents, etc., with good application effects.