The Physiochemical Properties Of Excipients Biology Essay

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Xanthan gum is used in oral and topical pharmaceutical formulations, cosmetics, and foods as a suspending and stabilizing agent. It is used as a thickening and emulsifying agent. It is nontoxic, compatible with many other pharmaceutical ingredients, and it has good stability and viscosity properties in a wide pH and temperature range; . Xanthan gum gels show pseudo plastic behavior, the shear thinning directly proportional to the shear rate. The viscosity returns to normal immediately on release of shear stress.

When xanthan gum is mixed with inorganic suspending agents, such as magnesium aluminum silicate, or organic gums, synergistic rheological effects occur. In general, mixtures of xanthan gum and magnesium aluminum silicate in ratios between 1 : 2 and 1 : 9 produce the optimum properties. Similarly, optimum synergistic effects are obtained with xanthan gum : guar gum ratios between 3 : 7 and 1 : 9.

Although primarily used as a suspending agent, xanthan gum has also been used to prepare sustained-release matrix tablets.

Xanthan gum has been incorporated in an ophthalmic liquids, it interacts with mucin, helping in the prolonged retention of dosage form in the pre corneal area. xanthan gum is also used as an excipient for spray-drying and freeze-drying processes for better results. Xanthan gum is used to increase the bioadhesive strength in vaginal formulations and acts as a binder in colon specific drug delivery systems. Xanthan gum is also used in cosmetics and used as a thickening agent in shampoo.

Description

Xanthan gum can be find as a cream- or white-colored, odorless, free-flowing, fine powder.

Particle size distribution: Different grades with different particle sizes are available; for example, 100% less than 180 μm in size for Keltrol CG; 100% less than 75 μm in size for Keltrol CGF; 100% less than 250 μm, 95% less than 177 μm in size for Rhodigel; 100% less than 177 μm, 92% less than 74 μm in size for Rhodigel 200.

Solubility:

  Partially insoluble in ethanol and ether; soluble in cold or warm water.

Viscosity (dynamic):

1200-1600 mPa s (1200-1600 cP) for a 1% w/v aqueous solution at 25°C.

Stability and Storage Conditions:

Aqueous solutions are stable at a wide pH range (pH 3-12), although they has maximum stability at pH 4-10 and temperatures of 10-60°C. Xanthan gum solutions of less than 1% w/v concentration adversely affected by higher than ambient temperatures: for example, viscosity will be reduced. Solutions also stable in the presence of enzymes, salts, acids, and bases. The bulk materials have to be stored in a well-closed container in a cool, dry place.

Lactose, Monohydrate

Synonyms:-

Lactochem Coarse Crystals, Pharmatose DCL 15, NF Lactose 310

Chemical Name and CAS Registry Number:-

O-β-D-Galactopyranosyl-(1→4)-α-D-glucopyranose monohydrate [64044-51-5]

Structural Formula:-

Functional Category:-

Binding agent; diluents for dry-powder inhalers; tablet binder; tablet and capsule diluents.

Applications in Pharmaceutical Formulation:-

Lactose is used as a filler or diluents in tablets and capsules, and has a limited involve in lyophilized products and infant formulas. Lactose is also used as diluents in dry-powder inhalation. Lactose are commercially available that have different physical properties such as particle size distribution and flow characteristics.

Lactose added to freeze-dried solutions to increase plug size and aid cohesion. It is also used in combination with sucrose (approximately 1: 3) to prepare sugar-coating solutions.

Description:-

Lactose shows as various isomeric forms, depending on the crystallization and drying conditions, i.e. α-lactose monohydrate, β-lactose anhydrous and α-lactose anhydrous. The stable crystalline forms of lactose are α-lactose monohydrate, β-lactose anhydrous and stable α-lactose anhydrous.

Lactose available as white to off-white crystalline particles or powder. It is odorless and slightly sweet-tasting; α-lactose is approximately 20% as sweet as sucrose, while β-lactose is 40% as sweet.

Stability and Storage Conditions:-

There may be occurrence of mold growth under humid conditions (80% relative humidity and above). Lactose sometimes develop a brown coloration on storage, the reaction being increased by warm, damp conditions. The purity of different lactose's can vary and color evaluation may be important, if white tablets are being formulated.

Incompatibilities:-

Sometimes Mail lard-type condensation reaction is likely to occur in between lactose and compounds with a primary amine group forms brown or yellow-brown-colored products. Lactose incompatible with amino acids, aminophylline, 19 amfetamines, 20 and Lisinopril2.

POLYOX

They are white, free-flowing hydrophilic crystalline powders in a wide variety of molecular weight grades, ranging from one hundred thousand to eight million with an average particle size of around 150 μm. POLYOX NF water-soluble resins has applications in pharmaceutical products, such as in controlled release solid dose matrix systems, tablet binding, tablet coatings, Transdermal drug delivery systems, and mucosal bioadhesives and gastro-retentive dosage forms.

Common structure:

(-O-CH2-CH2-)n OH. They resemble chemical structure as PEG but has higher molecular weights. n = average number of oxyethylene groups. The ethylene oxide monomer is an epoxide ring. Two corners of the molecule consist of -CH2- linkages as shown in the third corner are oxygen, -O-. In the presence of a catalyst the monomer forms a chain having the repeat unit -CH2-CH2-O-.

Grades of POLYOX water soluble resins:

POLYOX resins supplied in different molecular weight grades and formulated as NF. the highest level of polyethylene oxide in an oral drug form currently being used is approximately 543 mg/tablet. 

POLYOX Water-Soluble Resins NF in Pharmaceutical Applications

POLYOX Water-Soluble Resin NF Product

Approximate Molecular Weight

Viscosity Range at 25°C, cP

5% Solution

2% Solution

1% Solution

WSR N-10

100,000

30 - 50

 

 

WSR N-80

200,000

55 - 90

 

 

WSR N-750

300,000

600 - 1,200

 

 

WSR N-205

600,000

4,500 - 8,800

 

 

WSR N-1105

900,000

8,800 - 17,600

 

 

WSR N-12K

1,000,000

 

400 - 800

 

WSR N-60K

2,000,000

 

2,000 - 4,000

 

WSR-301

4,000,000

 

 

1,650 - 5,500

WSR Coagulant

5,000,000

 

 

5,500 - 7,500

WSR-303

7,000,000

 

 

7,500 - 10,000

General properties:

High binding efficiency - POLYOX water-soluble resins has high-binding efficiency for pigments, fillers, and metal powders. Binders easily burn off in low temperatures with little or no tendency to char.

Crosslink ability - POLYOX water-soluble resins cross-linked to form gels which are highly water-retentive.

Film former excipient - POLYOX water-soluble resins forms into flexible films by thermoplastic processing and casting techniques. These films may be made of POLYOX water-soluble resins alone or blended by a wide variety of other polymers, like polyethylene, polystyrene, ethylene vinyl acetate, nylon, etc.

Low toxicity - POLYOX, water-soluble resins, has very low toxicity in animal studies by all routes of exposure. The maximum practical oral dose rates of about 2 g/kg of body weight do not have death nor are signs of toxicity observed. Because of their high molecular weights, the resins poorly absorbed from the GIT and are completely and rapidly eliminated. These resins are neither sometimes causes skin irritation nor sensitizers, nor they cause eye irritation as the dry powder or as aqueous solutions.

Flocculent activity - High molecular weight grades of POLYOX water-soluble resins effectively adsorb onto many colloidal materials and acts as efficient flocculating agents. They show high affinity to a number of materials, including silica, clays, oxidized coal fines, lignin's and paper fines.

Lubricity - POLYOX water-soluble resins impart a high degree of lubricity in contact with water.

Solubility or Thickening of organic solvents - POLYOX water-soluble resins are soluble and will thicken in variety of organic solvents at different temperatures. Organic solvents mostly haloge­nated hydrocarbons, various ketones, alcohols, aromatic hydrocarbons and esters. POLYOX water-soluble resins are not soluble in aliphatic hydrocarbon solvents, glycols, diols and aliphatic ethers.

Thickening power (aqueous) - POLYOX water-soluble resins are nonionic and fully water-soluble at all tempera­tures up to the boiling point of water. POLYOX water-soluble resins are effective thick­ening agents in fresh and salt water. Aqueous solutions are pseudo plastic.

Flow property - All grades of POLYOX water soluble resins flow relatively same. POLYOX contains silica (~1.5%) to help the flow ability.

Applications in Pharmaceutical Industries:

POLYOX successful use in extended release applications of osmotic pump technologies, hydrophilic matrices, gastro-retentive dosage forms and drug delivery systems such as Transdermal and mucoadhesive technologies.

POLYOX resins also have a number of benefits:

Wide range of molecular weights offers formulation flexibility

application in direct compression and granulation

quick hydration and swelling for use in osmotic pump technologies

rapid hydration and gel formation for use in hydrophilic matrices

Magnesium Stearate

1. Nonproprietary Names

BP: Magnesium stearate

JP: Magnesium stearate

PhEur: Magnesii stearas

USPNF: Magnesium stearate

2. Synonyms

Magnesium octadecanoate; octadecanoic acid, magnesium salt; stearic acid, magnesium salt.

4. Empirical Formula and Molecular Weight

C36H70MgO4 591.34

The USPNF 23 describes magnesium stearate as a compound of magnesium with a mixture of solid organic acids consists of variable proportions of magnesium stearate and magnesium palmitate (C32H62MgO4).

5. Structural Formula

[CH3(CH2)16COO]2Mg

6. Functional Category

Tablet, capsule lubricant.

7. Applications in Pharmaceutical Formulation

Magnesium stearate widely used in cosmetics, foods, and pharmaceutical formulations. Primarily used as lubricant in capsule and tablet manufacture in concentrations between 0.25% and 5.0% w/w.

8. Description

Magnesium stearate is very fine, light white, precipitated or milled, having a faint odor of stearic acid and has characteristic taste. The powder is greasy to touch and readily adheres to the skin.

9. Typical Properties

Solubility:

Practically insoluble in ethanol, ethanol (95%), ether and water; slightly soluble in warm benzene and warm ethanol (95%).

10. Stability and Storage

Magnesium stearate is stable and should be stored in a well-closed container in a cool, dry place.

11. Incompatibilities

Incompatible with strong acids, alkalis, and iron salts. Avoid mixing with strong oxidizing materials. Magnesium stearate cannot be used in products containing aspirin, some vitamins, and most alkaloid salts.

Povidone

Nonproprietary Names

BP: Povidone

JP: Povidone

PhEur: Povidonum

USP: Povidone

Synonyms

E1201; Kollidon; plasdone; poly[1-(2-oxo-1-pyrrolidinyl)ethylene]; polyvidone; polyvinylpyrrolidone; PVP; 1-vinyl-2-pyrrolidinone polymer.

Approximate molecular weights for different grades of Povidone.

K-value

Approximate molecular weight

12

2 500

15

8 000

17

10 000

25

30 000

30

50 000

60

400 000

90

1 000 000

120

3 000 000

Structural Formula

Functional Category

Disintegrate; dissolution aid; suspending agent; tablet binder.

Applications in Pharmaceutical Formulation

Povidone is used in a variety of pharmaceutical formulations; it is primarily used in solid-dosage forms. Povidone solutions used as binders in wet-granulation processes. Povidone is added to powder blends in the dry form and granulated in situ by the addition of water, alcohol, or hydro alcoholic solutions. Povidone used as solubiliser in oral and parenterals formulation and has shown to enhance dissolution of poorly soluble drugs from solid-dosage forms. Povidone solutions can also be used as coating agents.

Povidone is used as a suspending, stabilizing, or viscosity-increasing agent in a number of topical and oral suspensions and solutions.

Uses of Povidone.

Use

Concentration (%)

Carrier for drugs

10-25

Dispersing agent

Up to 5

Eye drops

2-10

Suspending agent

Up to 5

Tablet binder, tablet diluents, or coating agent

0.5-5

Description

Povidone is as a fine, white to creamy-white colored, odorless and hygroscopic powder. Povidone with K-values equal to or lower than 30 are manufactured as spray-drying and occur as spheres. Povidone are manufactured by drum drying and occur as plates.

Melting point:

 Softens at 150°C.

Particle size distribution:

Kollidon 25/30: 90% >50 μm, 50% >100 μm, 5% >200 μm.

Kollidon 90: 90% >200 μm, 95% >250 μm.

Solubility:

Freely soluble in acids, chloroform and ethanol (95%), ketones, methanol, and water; partially insoluble in ether, hydrocarbons, and mineral oil. In water, the concentration of solution is limited by viscosity of the resulting solution, which is a function of the K-value.

Dynamic viscosity of 5% w/v povidone (Kollidon) solutions in ethanol (95%) and propan-2-ol at 25°C.

Grade

Dynamic viscosity (mPa s)

Ethanol (95%)

Propan-2-ol

K-12PF

1.4

2.7

K-17PF

1.9

3.1

K-25

2.7

4.7

K-30

3.4

5.8

K-90

53.0

90.0

Stability and Storage

Povidone darkens on heating at 150°C, with a reduction in aqueous solubility. It is stable to a short period of heat exposure around 110-130°C; steam sterilization of an aqueous solution does not alter its properties. Aqueous solutions are susceptible to mold growth and require addition of preservatives.

Povidone stored under normal conditions without undergoing decomposition or degradation. As the powder is hygroscopic, it should be stored in an airtight container in a cool, dry place.

Incompatibilities

Povidone has compatibility in solution with a wide range of inorganic salts, natural and synthetic resins.

Sodium alginate

Sodium alginate is the sodium salt of alginic acid. Its empirical formula is NaC6H7O6. Sodium alginate is a gum, extracted from the cell walls of brown algae

Uses

It is a flavorless gum; it is used in the foods industry to increase viscosity and as emulsifier. It is also used in preparation of dental impressions.

Sodium alginate is a good chelator for pulling radioactive toxins from the body, such as iodine-131 and strontium-90. It is also used in immobilizing enzymes by inclusion.

As a food additive, sodium alginate is used in the production of gel-like foods. It is also used in the biological experiments for the immobilization of cells to obtain important products like alcohols, organic acids, etc.

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