INTRODUCTION TO PRESERVATIVES (Pharmaceutics).pptx

LET'S KNOW ABOUT PRESERVATIVE.

A preservative is a natural or synthetic substance that is added in the products like foods, pharmaceuticals, paints, biological samples, wood, etc., to avoid decomposition by microbial growth or by unwanted chemical changes. These are chemicals that are commonly added to many foods and pharmaceutical products in order to extend their shelf life.

1. By- shubham kumar m. Pharm (pharmaceutics) INTRODUCTION TO PRESERVATIVES

2. Definition A preservative is a natural or synthetic substance that is added in the products like foods, pharmaceuticals, paints, biological samples, wood, etc., to avoid decomposition by microbial growth or by unwanted chemical changes. These are chemicals that are commonly added to many foods and pharmaceutical products in order to extend their shelf life. Preservatives are added especially, to the products having greater water content to prevent them from alteration and degradation by microorganisms while storing. Preservatives are added in foods to prevent growth of bacteria, yeasts, or molds that may cause a disease.

3. Ideal Properties of Preservatives Non-irritant Non-toxic Physically and chemically stable Compatible with other ingredients Effective antimicrobial activity Potent at low concentrations Maintains activity throughout shelf life

4. Types of Preservatives Based on Mechanism of Action : Antioxidants : Inhibit oxidation (e.g., BHA, BHT) Antimicrobial Agents : Prevent microbial growth (e.g., sodium benzoate ) Chelating Agents : Prevent degradation (e.g., EDTA) Based on Source : Natural : Derived from natural sources (e.g., neem oil, salt ) Artificial : Chemically synthesized (e.g., sorbates , nitrites)

5. Mechanism of Action Following mechanisms enable the preservatives to interfere with the growth, multiplication and metabolism of the microorganisms: By modifying the permeability of the membrane. By denaturing the enzymes and other cellular proteins. By carrying out oxidation of cellular constituents. By the process of hydrolysis.

6. Selection Criteria for Preservatives Broad-spectrum effectiveness Stability in low concentrations Non-reactivity with other ingredients Soluble in the desired vehicle Odorless , tasteless, and colorless pH stability Favorable partition coefficient Non-toxic and non-irritating

7. Advantages of Preservatives The advantages of preservatives are as follows: They help in maintaining the consistency with the texture and provide thickness. They also increase the appearance of the product to make it look edible and safe to consume for a respectable amount of time. They can keep food fresh to consume for an extended period of time. They prevent spoilage of food caused by the bacteria. They prevent change in colour , texture or flavor of food.

8. Disadvantages of Preservatives Benzoates : Allergic reactions and potential brain damage Butylates : Linked to high blood pressure and cholesterol BHA : Potential liver disease and cancer risk Caramel Color : Genetic effects and carcinogenic potential Sodium : Risk of high blood pressure

9. Uses of Preservatives Ethanol and Aqueous Ethanol Solutions: They slow down the rate of decay of biological material by killing bacteria. Although, it is mainly used as a solvent, it can also be used as a disinfectant and as an antimicrobial preservative in solutions. Alpha Tocopherol : It is used as preservative of colours and flavours of food by delaying deterioration, rancidity and discolouration due to oxidation. Benzoic Acid: It is used in the form of sodium or potassium salts of benzoic acid for preserving the foodstuffs, drugs and cosmetics. It is generally used in the concentration of 0.1% w/v and remains non-toxic until used in large quantities.

10. Sodium Benzoate: It is mainly used as an antimicrobial preservative in cosmetics, foods, and pharmaceuticals. It is used in oral medicines at 0.02–0.5% concentration, 0.5% in parenteral products, and 0.1–0.5% in cosmetics. It is used in preference to benzoic acid in some situations, due to its higher solubility. However, at times, it may impart an unpleasant flavour to a product. It can be used as a tablet lubricant at 2–5%w/w concentrations. Its solution can be administered, orally or intravenously, in order to govern liver function. Parahydroxy Benzoate: These are widely used as preservatives in syrups and pharmaceutical preparations. Parahydroxy benzoates are the derivatives of benzoic acid, particularly, the esters of a p- hydroxy benzoic acid. Most commonly used preservatives in pharmaceutical industries are methyl, ethyl and propyl parabens . Ascorbic Acid: It is used as an antioxidant in food and in aqueous pharmaceutical formulations at 0.01–0.1% w/v concentration. It can be used to adjust the pH of solutions for injection, and as assistant for oral liquids. It has also been recognised as a stabilising agent in mixed micelles containing tetrazepam .

11. Salicylic Acid and Salicylates: They are widely used as a preservative in food and as a biocide in certain consumer products. Phenol (Carbolic Acid): In the concentration of 0.5% w/v phenol acts as a bactericide in multi-dose injections, gargles and mouth washes. In ear drops and oily injections, it is used in 6.4% w/v concentration. Sodium Chloride: It is widely used in a variety of parenteral and non-parenteral pharmaceutical formulations to mainly produce isotonic solutions. It can be used as a channelling agent and as an osmotic agent in the cores of controlled-release tablets. It can be used to control drug release from microcapsules and as a porosity modifier in tablet coatings.