The role of pvp va copolymer

Introduction of PVPVA copolymer:

PVPVA copolymer is a water-soluble copolymer synthesized from monomer N-ethylene-pyrrolidone (NVP) and vinyl acetate (VAc) in a certain proportion

Polymer, divided into cosmetic grade and pharmaceutical grade two grades, of which pharmaceutical grade products are mainly PVP-VA64, in the United States

Pharmacopoeia, European Pharmacopoeia and Japanese pharmacopoeia

Included.

PVP/VA copolymers are thermoplastic resins with molecular weights ranging from 20M to 50M. Glass conversion temperature from 55°C to 109°C, with the

increase of VP content, suction

Water performance increases. Pharmaceutical grade PVP-VA64 copolymer is a kind of high performance film forming adhesive. High solubility in water and a variety

of organic solvents, high adhesion, and has the ability to complex. Although its unique properties can be used in the formulation of pharmaceutical preparations

and afterbirth materials, it is currently mainly used as a tablet binder.

 

 

Copolymer molecular structure formula

In general, the weight average molecular weight of the copolymer of n-vinylpyrrolidone and vinyl acetate is between 45,000 and 70,000 (K value is about 28 to

36). On account of

Vinyl acetate is easy to self-polymerize in water-based system, in order to make the product colorless and transparent and improve the degree of polymerization to

obtain high molecular weight copolymerization products, it is necessary to control the reaction temperature,

The concentration of initiator and chain transfer simultaneously inhibited the autoaggregation of vinyl acetate.

Second, product characteristics

1. General nature

Chemical formula :(C6H9NO)n x (C4H6O2)m(n≈1.2m)

CTFA Name :VinyPyrrolidone/Vinyl Acetate Copolymers; Poly(N-VinylPyrrolidone/Vinyl Acetate)

CAS code :25086-89-9

Molecular weight:

(111.1)nx (86.1)m g/mole (n≈1.2m)

Appearance: Liquid products are transparent, colorless or light yellow in most cases; Powder product is white

Odor: Slight specific odor

Density :1.270(25℃)

2. Physical characteristics

① Solubility:

Pharmaceutical grade PVP-A64 dissolves easily in water, and its concentration is limited only by the viscosity of the solution. It can also be found in ethanol,

isopropyl alcohol, 1, 2-propylene glycol,

Glycerin, methylene chloride, low molecular weight polyvinyl alcohol (PEG), and a mixture of water and any of these solvents, formulated at a concentration of

more than 10%

A solution of… But it is slightly soluble in ether, cyclic hydrocarbon, aliphatic hydrocarbon, alicyclic hydrocarbon and so on.

② viscosity

The viscosity of pharmaceutical grade PVP-A64 solution is greater in isopropyl alcohol than in water (FIG below), as measured by a capillary viscometer at 25 ° C.

Pharmaceutical grade PVP-A64 with 1% concentration has a viscosity range of less than 1.4mPas at 25℃ in water, and still has a relatively low viscosity when the

concentration reaches 10%.

Viscosity diagram of PVP-A64 in water and isopropyl alcohol

The experimental results show that the viscosity of a solution with a concentration of 10% in water (about 8mpas) and in isopropyl alcohol (about 10mpas) is

almost unchanged at temperatures of about 40 ° C. It is this advantage that can be widely used in granulation and various types of spray solutions.

The viscosity of pharmaceutical grade PVP-A64 aqueous solution at 20% concentration remains unchanged over a wide ph range. However, when it is mixed with a

strong acid or base solution, vinyl acetate may saponify, especially after the solution has been left for several hours, to a certain extent, resulting in a change in

the viscosity of the solution.

③ hygroscopicity

The pharmaceutical grade PVP-A64 has low water absorption. It absorbs only one-third of the water absorbed by water-soluble polyethylpyrrolidone (PVP-K series).

As shown in the figure below, a certain degree of water absorption is beneficial when used as an adhesive in the manufacture of tablets or in pelletizing solutions.

However, when used as a film coating agent as a tablet, or in a formulation with water-sensitive drugs, water absorption may be detrimental to the stability of

coated tablets and those drugs that are extremely sensitive to water. Thus, when the formulation contains water-sensitive drugs, pharmaceutical grade PVP-A64 is

a useful alternative to the polyethylpyrrolidone PVP-K series.

Pharmaceutical grade PVP-A64 has excellent adhesion and film formation characteristics, as well as its adhesion ability to hydrophilic and hydrophobic surfaces and

low water absorption, so its application in pharmaceutical products is very wide.

④K value

According to the European and American Pharmacopoeia, the average molecular weight of the polymer can be expressed as a K value. The K value is calculated by

the relative viscosity in 1% aqueous solution.

According to the United States Pharmacopeia, the relative viscosity of pharmaceutical grade PVP-A64 is 1.18-1.31, and it can be concluded that the K value is

within the limits of 25.4 and 34.1.

Iv. Application

1. Cosmetics industry:

In the production of cosmetics, people use its excellent physiological inertia, film formation, dispersion and colloidal protection, complexing, bonding, moisture

absorption properties, can play emulsification, thickening, moisturizing, pigment dispersion, reducing irritation and hair styling and other functions, for styling

hairspray, hair cream, mousse, facial mask, bath, shampoo and other indispensable raw materials in the production of cosmetics. Cosmetic grade products can be

used as styling agents and film formers and are widely used in hair care and styling products. It has excellent compatibility characteristics for aerosol and non-

aerosol products. VA55 and VA37 are particularly suitable for use in eruption products. For liquid hairspray, hairspray and mousse, we recommend VA64 and VA73.

With the increase of VP content in the product, the hygroscopic property of the product increases, which can enhance the affinity for hair, and because of its non-

ionic properties, it still maintains the excellent characteristics of easy cleaning and combing. Through the use of different specifications of resin, can meet a variety

of different humidity climate conditions

Compared with the cosmetics made of natural shellac, the cosmetics made of this raw material have the characteristics of good luster, strong elasticity, easy

combing, non-brittle, non-stick and comfortable after use.

2. Pharmaceutical Industry:

The vinylpyrrolidone component of the polymer enables pharmaceutical grade PVPVA to dissolve various drugs, while the vinyl acetate component allows it to form

a strong, transparent film. Therefore, it can be used in various drug dosage forms, such as adhesives for tablets, film coating and sustained release agents.

In addition, the polymer is not only an effective adhesive for tablets, but also an effective plasticizer. The tablets prepared by this copolymer have low brittleness

and are not prone to fragmentation. There is less tendency to stick in wet conditions. Therefore, the granulation of water-sensitive materials can replace POvidone

K series products and cellulose derivatives.

The combination of water-insoluble and slightly water-soluble substances can produce long-acting or slow-release products by wet or dry granulation method.

Water-insoluble, low-melting solids can be melted together with slightly water-soluble materials and drugs to form solid dosage forms that can control the diffusion

rate of the added drugs. The drug can also be coated with water insoluble and water-soluble materials, and the drug can be released through the pores of the

coating film to achieve the purpose of sustained drug release.

For example, since pharmaceutical grade PVP-VA64 is soluble in organic solvents, water-insoluble ingredients that prevent the release of the drug can be dissolved

in the organic solvent together with the polymer, and the matrix formed around the drug will play a role in regulating the diffusion or dissolution rate of the drug.

Examples of medicinal grade PVP-A64 being used with drugs have been reported.