Application of Povidone in Pharmaceutical Industry

With the development of pharmaceutical preparation technology, povidone has been widely used as the pharmaceutical auxiliary material of non-ionic water-soluble polymer compounds. However, different types of povidone need to be selected for different purposes, and there are many technical details in its application that need special attention from users. In this paper, the author combined with the actual production situation of the first line, respectively from its use as a binder, coprecipitation agent, co-solvent, etc..

-- According to the excellent physiological compatibility of povidone series pharmaceutical excipients, it is an inherent and unique product property. Till now, it has become one of the three major synthetic pharmaceutical excipients, together with cellulose derivatives and acrylic compounds.

Povidone series can be used in various types according to the K value, among which the most widely used varieties are K15, K30 and K90. The Chinese pharmacopoeia only accepts the quality standard of K30, while the British and American pharmacopoeia accepts all the povidone K series as an overall standard. Povidone, as an auxiliary material for medicine, has many preparation USES, and its application details deserve attention.

1. The use of povidone in the binder helps to produce compressible particles that can flow freely, resulting in tablets with strong solubility and good hardness. Generally, povidone K30 is used as a binder. The dosage of povidone K30 in tablets is generally 2% ~ 5%, and the concentration is generally 0.5% ~ 5%. For loose materials, povidone K90 with strong bonding ability can be selected, and the general dosage is less than 2%. Since povidone is soluble in both water and ethanol, the solution of povidone can be used to granulate the water-sensitive, heat-sensitive and volatile drugs, which not only solves the problem of drug stability, but also reduces the drying temperature and shortens the drying time.

Special attention should be paid to the use of povidone as binder in effervescent tablets. Since water is not allowed in the preparation of effervescent tablets, povidone, which is soluble in both water and anhydrous ethanol, becomes an ideal binder. The vinyl pyrrolidone - vinyl acetate copolymer is the best adhesive for preparing effervescent tablets.

2. Coprecipitant has many drugs with good efficacy, but its bioavailability is reduced due to its low solubility in water. Povidone molecules of carbonyl and undissolved drug molecules together by hydrogen bonds, the active hydrogen atoms make drug molecules amorphous state to enter completely water soluble macromolecular, povidone and inhibit the generation and growth of the undissolved drug molecules crystallize, and become oversaturated, can greatly improve the solubility of difficult soluble drugs.

Generally speaking, the dissolution rate V of polyvidone with different K values and most drugs produced coprecipitates follows the rule of VK15 < VK30 < VK90, but the coprecipitates formed with nitopyridine and phenytoin are the exception. How to choose the right coprecipitation agent, the manufacturer should consider and choose it according to the product characteristic.

3. As a cosolvent or dispersion stabilizer, povidone is also widely used in injection as a cosolvent or crystal growth inhibitor. This solution-enhancing effect is mainly caused by the combination of drugs and povidone. It is worth noting that, since the diameter of the human kidney capillary is about 7 nm, the polyvidone entering the human blood can be successfully discharged through the renal tubules only when the spiral body is less than 7 nm, that is, the corresponding molecular weight is less than 30000. Therefore, the molecular weight of polyvidone used as an injection should not be greater than 30000. Since povidone is the product of free radical polymerization, there exists the problem of molecular weight distribution. In order to ensure that povidone used for injection does not contain products with molecular weight greater than 30,000, it is recommended to use povidone with an average molecular weight of about 2500, and povidone K12 and povidone K17 are generally used as the auxiliary solvent of injection.

4. Coating or film forming agent in coating, the high bonding force of povidone increases the adhesive force of coating on the pharmaceutical substrate; Excellent dispersibility increases the stability of coating suspension and avoids the recombination and migration of pigment. Excellent film formation can prevent fine cracks on the coating surface during drying. K25 and K30 are mainly used as coating materials in povidone, and the domestic market of vinyl pyrrolidone - vinyl acetate copolymer as coating materials has also been widely used.

5. Slow-release or controlled-release of drugs in the preparation of insoluble or soluble skeletal sustained-release preparations, povidone is often used as a pore-forming agent to adjust the dosage of povidone to adjust the drug release rate, and the optimal drug dissolution mode can be obtained by using the appropriate preparation process. Polyvidone K90 with high molecular weight can be used to prepare hydrophilic gel type sustained release tablets, and the release rate can be adjusted by changing the proportion of the matrix material to the dosage of drugs.

In addition, povidone series is also widely used in eye medicine auxiliary agents, capsule fluid agent. With the continuous improvement of domestic pharmaceutical preparation level, povidone will be more and more widely used, and its application prospect will be more optimistic.