Formulation And Evaluation Of Losartan Potassium Buccal Patches Biology Essay


Hypromellose powder is a stable material, although it is hygroscopic after drying. Solutions are stable at pH 3-11. Increasing temperature reduces the viscosity of solutions. Hypromellose undergoes a reversible sol-gel transformation upon heating and cooling, respectively. The gel point is 50-908C, depending upon the grade and concentration of material. Aqueous solutions are comparatively enzyme-resistant, providing good viscosity stability during long-term storage. However, aqueous solutions are liable to microbial spoilage and should be preserved with an antimicrobial preservative: when hypromellose is used as a viscosity-increasing agent in ophthalmic solutions, benzalkonium chloride is commonly used as the preservative. Aqueous solutions may also be sterilized by autoclaving; the coagulated polymer must be redispersed on cooling by shaking. Hypromellose powder should be stored in a well-closed container, in a cool, dry place.

Hydroxypropyl cellulose powder is a stable material, although it is hygroscopic after drying. Aqueous solutions of hydroxypropyl cellulose are stable at pH 6.0-8.0, with the viscosity of solutions being relatively unaffected. Therefore, for prolonged storage, an antimicrobial preservative should be added to aqueous solutions. Solutions of hydroxypropyl cellulose in organic solvents do not generally require preservatives. Ultraviolet light will also degrade hydroxypropyl cellulose and aqueous solutions may therefore decrease slightly in viscosity if exposed to light for several months. Aqueous hydroxypropyl cellulose solutions have optimum stability when the pH is maintained at 6.0-8.0, and also when the solution is protected from light, heat, and the action of microorganisms. Hydroxypropyl cellulose powder should be stored in a well closed container in a cool, dry place.

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Carboxy methyl cellulose sodium is widely used in oral and topical pharmaceutical formulations primarily for its viscosity increasing properties. Viscous aqueous solutions are used to suspend powders intended for either topical application or oral and parenteral administration. Carboxymethyl cellulose sodium is additionally one of the main ingredients of self adhesive ostomy, wound care and dermatological patches where it is used to absorb wound exudates or trans epidermal water and sweat.

Applications: Hydroxyethyl cellulose is a nonionic, water-soluble polymer widely used in pharmaceutical formulations. It is primarily used as a thickening agent in ophthalmic and topical formulations, although it is also used as a binder and film-coating agent for tablets. It is present in lubricant preparations for dry eye, contact lens care, and dry mouth. The concentration of hydroxyethyl cellulose used in a formulation is dependent upon the solvent and the molecular weight of the grade. Hydroxyethyl cellulose is also widely used in cosmetics.

Description: Hydroxyethyl cellulose occurs as a light tan or cream to white colored, odorless and tasteless, hygroscopic powder.

Typical Properties:

Ash: 2.5% w/w for Cellosize;

3.5% w/w for Natrosol.

Density (bulk): 0.35-0.61 g/cm3 for Cellosize;

0.60 g/cm3 for Natrosol.

Melting point: Softens at 135-140°C, decomposes at about 205°C.

Solubility: Hydroxyethyl cellulose is soluble in either hot or cold water, forming clear, smooth, uniform solutions. Practically insoluble in acetone, ethanol (95%), ether, toluene, and most other organic solvents. in some polar organic solvents, such as the glycols, hydroxyethyl cellulose either swells or is partially soluble.

Stability and Storage Conditions:

Hydroxyethyl cellulose powder is a stable though hygroscopic material. Aqueous solutions of hydroxyethyl cellulose are relatively stable at pH 2-12 with the viscosity of solutions being largely unaffected. However, solutions are less stable below pH 5 owing to hydrolysis. At high pH, oxidation may occur. Solutions may be subjected to freeze-thawing, high-temperature storage, or boiling without precipitation or gelation occurring. For prolonged storage, an antimicrobial preservative should therefore be added to aqueous solutions. Aqueous solutions of hydroxyethyl cellulose may also be sterilized by autoclaving. Hydroxyethyl cellulose powder should be stored in a well closed container, in a cool, dry place.


Structural Formula:

Synonyms: E1201; Kollidon; Plasdone; Polyvidone; Povidone.

Chemical name and CAS Registry Number:

1-Ethenyl-2-pyrrolidione homopolymer, [9003-39-8]

Emperical Formula: (C6H9NO) n

Molecular Weight: 2,500-3,000,000

Functional Category: Disintegrant; dissolution aid; suspending agent; tablet binder.

Applications: Although povidone is used in a variety of pharmaceutical formulations, it is primarily used in solid-dosage forms. In tableting, povidone solutions are used as binders in wet-granulation processes Povidone is also added to powder blends in the dry form and granulated in situ by the addition of water, alcohol, or hydroalcoholic solutions. Povidone is used as a solubilizer in oral and parenteral formulations and has been shown to enhance dissolution of poorly soluble drugs from solid-dosage forms.

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Description: Povidone occurs as a fine, white to creamy-white colored, odorless or almost odorless, hygroscopic powder. Povidones with K-values equal to or lower than 30 are manufactured by spray-drying and occur as spheres. Povidone K-90 and higher K-value povidones are manufactured by drum drying and occur as plates.

Typical Properties

Acidity/alkalinity : pH =3.0-7.0 (5% W/V aqueous solution).

Density (bulk) : 0.29-0.39 g/ cm3 for Plasdone.

Density (tapped) : 0.39-0.54 g/ cm3 for Plasdone.

Density (true) : 1.180 g/ cm3

Flowability : 20 g/s for povidone K-15;

16 g/s for povidone K-29/32

Melting point : Softens at150°

Moisture content: Povidone is very hygroscopic, significant amounts of moisture being absorbed at low relative humidities.

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

Viscosity: The viscosity of aqueous povidone solutions depends on both the concentration and the molecular weight of the polymer employed.

Stability and Storage conditions:

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

Povidone may be stored under ordinary conditions without undergoing decomposition or degradation. However, since the powder is hygroscopic, it should be stored in an air tight container in a cool, dry place.


Structural formula :

Synonyms : 1,2 - benzene dicarboxylic acid dibutyl ester; n-butyl phthalate; DBP; dibutyl benzene - 1,2- dicarboxylate; di-n-butyl phthalate; Kodaflex DBP; Phthalic acid dibutyl ester.

CAS Registry Number : [84-74-2]

Empirical formula: C16H22 O4

Molecular Weight: 278.35

Functional category: Dibutyl phthalate is used as a plasticizer in film coatings; It is also used as an insect repellant, primarily for the impregnation of clothing.

Description: A clear, colorless or faintly colored oily liquid.

Typical properties :

Boiling Point: 340OC

Density: ï‚» 1.05g/cm3

Flash point: 1710C (Open cup)

Freezing point: -350C

Refractive index: nD20 = 1.491 - 1.493

Viscosity(dynamic) 15m Pa s (15cp) at 250C

Solubility : Very soluble in acetone, benzene, ethanol (95%) and ether; soluble 1 in 2500 of water.

Stability and Storage Conditions:

Dibutyl phthalate should be stored in a well-closed container in a cool, dry, location. Containers may be hazardous when empty since they can contain product residues such as vapors and liquids.

GLYCERIN122 (vii)

Structural formula:

Synonyms: Croderol; E422; Glycerine; Glycon G-100; Kemstrene; Pricerine; 1,2,3 - Propanetriol; Trihydroxy propane glycerol.

Chemical Name and CAS Registry Number :

Propane - 1,2,3, - triol , [56-81-5]

Empirical formula: C3H8 O3

Molecular Weight: 92.09

Applications: Glycerin is used in a wide variety of pharmaceutical formulations including oral, otic, ophthalmic, topical and parenteral preparations. It is also used in cosmetics and as a food additive.

In topical pharmaceutical formulations and cosmetics, glycerin is used primarily for its humectant and emollient properties. In parenteral formulations glycerin is mainly used as a solvent. In oral solutions glycerin is used as a sweetening agent, anti-microbial preservative and viscosity increasing agent. Glycerin is also used as a plasticizer of gelatin in the production of soft gelatin capsules and gelatin suppositories. Glycerin is additionally employed as a therapeutic agent in a variety of clinical applications.

Functional Category: Antimicrobial preservative; emollient; humectant; Plasticizer; solvent; sweetening agent; Tonicity agent.

Description: Glycerin is a clear, colorless, odourless, viscous, hygroscopic liquid; it has a sweet taste, approximately 0.6 times as sweet as sucrose.

Typical properties:

Boiling point: 290oC (With decomposition)

Density: 1.2656 g/cm3 at 15oC.

1.2636g/cm3 at 20oC.

1.2620g/cm3 at 25oC.

Flash point : 176oC(Open cup).

Hygroscopicity: Hygroscopic.

Melting point: 17.8oC .

Osmolarity: A 2.6%v/v aqueous solution is iso-osmotic with


Refractive Index: nD 15 = 1.4758.

nD 20 = 1.4746

nD 25 = 1.4730

Vapour Density (Relative): 3.17(air=1).



Solubility at 20oC

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Slightly soluble


Practically insoluble.


Practically insoluble.

Ethanol (95%)



1 in 500

Ethyl acetate

1 in 11




Practically insoluble



Concentration of Aqueous solutions(%w/w

Viscosity at 20oC(m pas)