ADDED SUBSTANCES

PREPARED BY MASH'HOOD MAHMOOD KHAN SHAHID UZAIR AMIRSAIF ULLAH KHAN

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ADDED SUBSTANCES:-

“Additive substances or additives are generally employed in parenteral preparation to enhance its physical and chemical stability i.e shelf life or esthetic appearance.”

CRITERIA OF ADDED SUBSTANCE:-

• It must be non toxic in quantity administered to the patient• It should not interfere with therapeutic efficacy nor with the

assay of active therapeutic compound• It must be prevented from adversely affecting the product

TYPES OF PARENTERAL ADDITIVES:-AntimicrobialsAntioxidantsBuffersBulking agentChelating agentProtectantsSolubilizing agentSurfactantsTonicity adjusting agentsAntifungal agentsHydrolysis inhibitorsAntifoaming agents

ANTIMICROBIALS AGENTS:-A suitable preservative system is required in all multiple dose parenteral products to inhibit the growth of microorganism accidentally introduced during withdraw of individual doses. Preservatives may be to single dose parenteral products that are not terminally sterilized as a sterility assurance measure i.e. to prevent the growth of any microorganism that could be introduced of there were any inadvertent breach of asepsis during filling operations

EXAMPLE:-• Benzalkonium chloride• Benzethonium chloride• Benzyl alcohol• Phenol• Metacresol

ANTIOXIDANT:-Many drugs in solutions are subject to oxidative degradation. Such reaction are mediated by free radicals or by molecular oxygen or removal of hydrogen . Oxidative decomposition is catalyzed by metal, hydrogen and hydroxyl ions. Drugs possessing a favorable oxidation potential will be especially vulnerable to oxidation. For example, a great number of drugs are formulated in the reduced form (e.g. epinephrine,morphine,ascorbic acid,e.t.c.) and are easily oxidized. By increasing the oxidation potential of the drug oxidation can be minimized. Salts of sulfur dioxide including bisulfite , metabisulfite and sulfite are the most common antioxidant used in aqueous parenteral.

BUFFERS:-Many drugs require a certain pH range to maintain product stability. Drug stability strongly depend on the pH of the solution. Change in pH may occur during storage by the following ways:-• By dissolving gas constituent in the product• By releasing of constituents from rubber closures or plastic components in contact with

the product• By dissolving of gas and vapours from airspace in the container• Reactions within the productBuffer system for parenterals consist of either a weak base or a salt of weak base or a weak acid or salt of weak acid

EXAMPLES:-• Acetic acid • Adipic acid• Citric acid• Sodium bicarbonate• Sodium carbonate

CHELATING AGENT:-Chelating metals are added to complex and thereby inactivate metals such as copper, iron , zinc that generally catalyze oxidative degradation of drug molecules. Sources of metal combination include raw material impurities solvents such as water, rubber stoppers, and containers and equipment employed in the manufacturing process.

EXAMPLE:-• Edetate disodium• Edetate tetrasodium

INERT GASES:-Another means of enhancing the product integrity of oxygen sensitive medicaments is by displacing the air the solution with nitrogen or argon. This technique may be made more effective by first purging with nitrogen or boiling the water to reduce dissolved oxygen. The container is also purged with nitrogen or argon before filling and may also be topped off with gas before sealing.

SOLUBILIZING, WETTING AGENTS:-Solubilizing agents are used to increased drug solubility by using non aqueous solventsExamples:-• Polyethlene glycol• Ethyl alcohol• Glycerin • Lecithin• povidone

SURFACTANTS:-Surfactants are used :-• To dispose a water insoluble drugs as a colloidal

dispersion• For wetting powder• To prevent crystal growth in a suspension• To provide acceptable syringability• For solubilizing steroids and fat soluble vitamins

EXAMPLE:-• Polyethylene• Sorbitan monooleate

TONICITY ADJUSTMENT AGENTS:-Isotonicity is important for parenteral preparation because the possibility that the product may penetrate red blood cell and cause hemolysis is greatly reduced if the solution is isotonic with blood i.e. the cells maintain their tone.Solution that less osmotic pressure than the blood plasma called hypotonic and solution that more osmotic pressure than the blood plasma called hypertonic. When introduce hypotonic solution cell may swell and offers brust because of diffusion of waterinto the cell i.e. hemolysis, if introduce hypertonic solution ,the cell may lose water and shrink.in sotonic solution the cell maintain their tone and the solution is isotonic with human erythrocytes.

EXAMPLES:-• Sodium chloride• Gelatin • Lactose• Dextrose• Sorbitol

PROTECTANT:-Protectants are used:-• To protect against loss of activity caused by some stress• To prevent the loss of active ingredients by adsorption to

process equipment or to primary packaging materialProtectants are used in the formulations of proteins.

EXAMPLE:-• Sucrose • Glucose• Maltose• Lactose

ALLAH HE HAFIZ