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Prevnar

Drug Description
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Pneumococcal 7-valent Conjugate Vaccine

(Diphtheria CRM197 Protein) FOR PEDIATRIC USE ONLY

DRUG DESCRIPTION

Pneumococcal 7-valent Conjugate Vaccine (Diphtheria CRM197 Protein), Prevnar®, is a sterile solution of saccharides of the capsular antigens of Streptococcus pneumoniae serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F individually conjugated to diphtheria CRM197 protein. Each serotype is grown in soy peptone broth. The individual polysaccharides are purified through centrifugation, precipitation, ultrafiltration, and column chromatography. The polysaccharides are chemically activated to make saccharides which are directly conjugated to the protein carrier CRM197 to form the glycoconjugate. This is effected by reductive amination. CRM197 is a nontoxic variant of diphtheria toxin isolated from cultures of Corynebacterium diphtheriae strain C7 (b197) grown in a casamino acids and yeast extract-based medium. CRM197 is purified through ultrafiltration, ammonium sulfate precipitation, and ion-exchange chromatography. The individual glycoconjugates are purified by ultrafiltration and column chromatography and are analyzed for saccharide to protein ratios, molecular size, free saccharide, and free protein.

The individual glycoconjugates are compounded to formulate the vaccine, Prevnar®. Potency of the formulated vaccine is determined by quantification of each of the saccharide antigens, and by the saccharide to protein ratios in the individual glycoconjugates.

Prevnar®is manufactured as a liquid preparation. Each 0.5 mL dose is formulated to contain:

2 mg of each saccharide for serotypes 4, 9V, 14, 18C, 19F, and 23F, and 4 mg of serotype 6B per dose (16 mg total saccharide); approximately 20 mg of CRM197 carrier protein; and 0.125 mg of aluminum per 0.5 mL dose as aluminum phosphate adjuvant. After shaking, the vaccine is a homogeneous, white suspension.