phr 113 / lecture 6 · pharmacognosy phr 113 / lecture 6. physical and chemical properties of...

Pharmacognosy PHR 113 / Lecture 6

Physical and chemical properties of carbohydrates

• Monosaccharide and disaccharides are crystalline compounds, soluble in water and sweet to taste.

• Disaccharides must be digested to monosaccharides before absorption into blood and used for energy production in cells.

• Polysaccharides are amorphous compounds, not soluble in water,not sweet to taste.

• They form suspensions instead of solution.• Must be digested before being absorbed.

Starch

Starch is composed of –• linear polysaccharide amylose with α(1,4)-linked glucose units

• branched polysaccharide amylopectin with α(1,4)-linked glucosechains and branch-points with α(1,6)-linkages.

Starch

α(1-4) linkage

α(1-6) linkage

α(1-4) linkage

Cellulose

A linear polymer of β-1,4-linked glucose

Glycogen

Glycogen is composed of –• linear polysaccharide with α(1,4)-linked glucose units

• branched polysaccharide with α(1,4)-linked glucose chains and branch-points with α(1,6)-linkages.

β-1,6 linkage

α-1,6 linkage

Pharmaceutical importance of carbohydrates

Starch:Binder. Diluent. Disintegrant.

Glucose: Granulating and Coating agent, Sweetener

Lactose:Anhydrous lactose- Filler and binder. Lactose mono hydrate –Filler (or) diluent.

Pharmaceutical importance of carbohydrates

Sucrose: Binding agent. Bulking agent. Sweetener. Tablet coatingagents. Diluent, plasticizer Excipient in Chewable tablets.

Powdered cellulose: Binder, Diluent, Lubricant, Disintegrant

Microcrystalline cellulose: Thickening agent.

Guar gum:Synonym - Guar flour, Jaguar gumBiological source - Cyamopsis tetragonolobus Linn.

Family- Leguminosae

Uses:• Binder and disintegrant• Emulsifying agent• Bulk laxative

Pharmaceutical importance of carbohydrates

Agar:Synonym: Agar-Agar, Vegetable gelatin.

Biological source: Gelidium amansii.Family- Gelidaceae

Uses:• Laxative• Emulsifying agent• Preparation of jellies• Preparation of suppositories

Pharmaceutical importance of carbohydrates

Acacia:Synonym - Gum acacia, Gum ArabicaBiological source - Acacia Arabica

Family- LeguminosaeUses:• Demulcent• Emollient• Suspending agent• Emulsifying agent• Binding agent• Stabilizing agent

Pharmaceutical importance of carbohydrates

Tragacanth

Synonym - gum tragacanth.

Biological source - Astragalus gummiferFamily- Leguminosae

Uses:• Demulcent• Emollient• Suspending agent• Emulsifying agent

Pharmaceutical importance of carbohydrates

Thank you

Mohammad Ahad A Khan, PhDAssistant Professor, Department of Pharmaceutical SciencesNorth South University, Bangladesh Room: SAC 1013email: mohammad.khan03@northsouth.eduCell: +880 17 0386 4707