Gels & jellies

introduction about gels & jellies & preparation methods

1. GELS & JELLIES Mr.Ravikumar R Patil Dr.Shivajirao Kadam College of Pharmacy Kasabe digraj, Sangli

2. INTRODUCTION GELS Gels are semisolid dosage form. In that dispersion of small or large molecules in an aqueous liquid vehicle. They produce jelly like consistency by the addition of a gelling agent. Gels are formed by using synthetic polymers such as carbomer 934 & cellulose such as hydroxypropylcellulose & hdroxypropylmethylcellulose . Tragacnth , pectin, agar natural gums are used in the formulation of gels.

3. As per NF , six polymers are used for gel formulation. Those are followings, Carbomers 910 Carbomer 934 Carbomer 934P Carbomer 940 Carbomer 941 And Carbomer 1342 Carbomer 940 produce highest viscosity betw. 40,000 & 60,000 centipoises in 0.5% aq. Solution.

4. Gels may thicken on standing, forming a thixotrope and must be shaken before use to liquefy the gel. In the gel contains drug substance with water. Also contain solvents such as, alcohol or propylene glycol. Antimicrobial preservatives used in gel formulation such as, methylparaben , propylparaben etc. It also contains stabilizers e.g. edetate disodium (EDTA). Medicated gels prepared for administration by various routes for eye, nose, vaginal & rectum.

5. CLASSIFICATION OF GELS Single- phase gel Two- phase gel In single phase gel contains macromolecules are uniformly distribute throughout the liquid with no apparent boundaries betw. macromolecules & the liquid. In two phase gel contains small separate particles also called as magma. E.g. Milk of magnesia (Magnesia magma) in that gelatinous precipitate of magnesium hydroxide.

6. TYPES OF GELS HYDROGELS XEROGELS ORGANOGELS

7. HYDROGELS A hydrogel is a network of polymer chains that are hydrophilic, sometimes found as a colloidal gel in which water is the dispersion medium. Hydrogels are highly absorbent(they can contain over 90% water) natural or synthetic polymeric networks. Hydrogels also possess a degree of flexibility very similar to natural tissue, due to their significant water content. Common ingredients include polyvinyl alcohol, sodium polyacrylate, acrylate polymers and copolymers with an abundance of hydrophilic groups.

8. Uses: As scaffolds in tissue engineering. As environment sensitivity detector. Sustained release DDS. Contact lenses. ECG medical electrode. Glue

9. XEROGELS Open network formed by the removal of all swelling agents from a gel. Xerogels usually retain high porosity (15–50%) and enormous surface area (150–900 m 2 /g), along with very small pore size (1–10 nm). When solvent removal occurs under supercritical conditions, the network does not shrink and a highly porous, low-density material known as an aerogel is produced.

10. Uses: IN DDS

11. ORGANOGELS An organogel is a non-crystalline, non-glassy thermo reversible (thermoplastic) solid material composed of a liquid organic phase entrapped in a three-dimensionally cross-linked network. The liquid can be, for example, an organic solvent, mineral oil, or vegetable oil. These systems are based on self-assembly of the structuring molecules.

12. Uses: In pharmacy used as drug carrier for TDDS. In cosmetics for application & stability and food industry.

13. Commonly Used Gelling Agents Acacia Pectin Starch Tragacanth Xanthan gum Alginic acid (seaweed) Animal/ vegatable fats: cocoa butter Gelatin Bentonite, veegum (magnesium aluminum silicate) Carboxymethylcellulose (CMC) and other cellulose derivatives Carbomer resins (Carbopols) Colloidal silicon dioxide Polyvinyl alcohol (PVA) Petrolatum, mineral oil/polyethylene gel.

14. Method of Formulation There are 3 methods: Fusion Method Cold Method Dispersion Method

15. Fusion Method In this method various waxy materials employed as gellant in non polar media. Drug was added when waxy materials melted by fusion. stirred slowly until uniform gel formed.

16. Cold Method Water was cooled to 4-10 c and placed it in mixing container. Gelling agent was slowly added and agitating until solution is complete. Maintained temperature below 10 c . Drug was added in solution form slowly with gentle mixing. Immediately transfer to container & allow to warm to R.T where upon liquid becomes clear gel.

17. Dispersion Method Gelling agent was dispersed in water with stirring at 1200 rpm for 30 min . Drug was dissolved in non-aqueous solvent with preservative. This solution was added in above gel with continuous stirring.

18. JELLIES INTRODUCTION Jellies are transparent or translucent non-greasy semisolid dosage form. They are less greasy compare gel. They are mainly used for mucous membrane for lubricating, antiseptic purpose. Jellies are also used for lubricating surgical gloves, catheters & rectal thermometers. Vaginal jellies & contraceptive jellies are also commonly used.

19. Medicated jellies contains a considerable amount of water therefore those are suitable for water soluble medicaments. Such as, anaesthetics, antiseptics and spermicides. They are unsuitable for insoluble medicaments. They are easy to apply. After evaporation of water they produce cooling sensation to the skin. When treatment is over, they can be easily removed by washing with water.

20. Preparation of Jellies Pharmaceutical jellies are usually prepared by adding a thickening agents. Such as tragacanth or carboxymethyl cellulose. Thickening agents is transferred into aqueous solution in which drug has been dissolved. The mass is triturated in mortar until a uniform product is obtained.

21. Following jelling agents are used… Tragacanth Sodium alginate Pectin Starch Gelatin Cellulose derivatives

22. Tragacanth It is commonly used for the preparation of lubricating, medicated & contraceptive jellies. For lubricating jellies 2 to 3 % For dermatological vehicle about 5% For medicated jellies 5%

23. Cont… Tragacanth jellies are also called bassorin paste. When tragacanth added in water it produce lumpy product. So, dispersing agents like alcohol, glycerin or a volatile oil is used to get a homogeneous preparation.

24. Sodium Alginate Those jellies are used as lubricants & for dermatological vehicles. In lubricants 1.5 to 2% & for dermatological vehicle 5 to 10% sodium alginate used. In that type of jellies alcohol, propylene glycol or glycerin used as dispersing agents.

25. Pectin Pectin is a very good gelling agent. Pectin used in various preparation of jellies including edible jellies. It is mainly used in dermatological jellies. Glycerin is used as humectant & dispersing agent. Pectin jellies prepared with suitable preservatives.

26. Starch Starch jellies prepared with combination of gelatin & glycerin. Starch glycerin jellies prepared by heating method or fusion method. Glycerin in large amounts i.e 50% may be act as preservative & humectant.

27. Gelatin Gelatin soluble in hot water. 2% gelatin produce jelly in a hot solution. Very stiff medicated jellies can be prepared by incorporating with 15% gelatin. Such jellies melted before use & after cooling to desired temperature it can be applied with brush on affected area. Those applied areas are cover with bandage. The dressing may be left in place after several weeks. Zinc gelatin jellies is also known as Unna’s paste.

28. Cellulose derivatives Methyl cellulose & sodium carboxy methyl cellulose are widely used for preparation of jellies. Those substances produce natural & stable jellies. Those afford good resistance against bacterial growth. Those produce strong film on the skin after drying on skin.

29. Evaluation test for Gels & Jellies pH determination Drug content Viscosity Spreadability

30. Spreadability S = M. L/M M = wt. tied to upper slide L = Length of glass slide T = Time taken to separate the slides