Semi solid dosage - PowerPoint Presentation

Slide1

Semi solid dosageform

OINTMENTS, CREAMS, PASTES, GELS,

Poulice and PLasterSlide2

Definition

Definition:

Semi solid pharmaceutical system comprise a body of product ,which when applied to skin or accessible mucous membranes tends to alleviate or treat a pathological condition or other protection against harmful environment.Slide3

Ideal properties ofSemi solid dosage formPhysical properties

Smooth texture

Elegant in appearenceNon dehydratingNon grittyNon greasy and non stainingNon hygroscopic

Physiological properties

Non irritatingDo not alter membrane function

Miscible with skin secretion

Application properties

Easy applicable with efficient drug release

High aqueous

washibilitySlide4

They contain one or more active ingredients dissolved or uniformly dispersed in a suitable base and any suitable excipients such as emulsifiers, viscosity increasing agents, anti microbial agents, antioxidents, or stabilizing agents. compositionSlide5

Advantage of semi-solid dosage form: It is used externally Probability of side effect can be reduce Local action First pass gut and hepatic metabolism is avoided. Patient compliance is increased, the drug termination is problematic cases is facilitated as compared with other routes of drug administration. Slide6

Disadvantages of semi-solid dosage form: There is no dosage accuracy in this type of dosage form The base which is used in the semi-solid dosage form can be easily oxidized. If we go out after using semi-solid dosage form problems can occur. Slide7

Classification (types)Slide8

OintmentsOintments are homogenous, translucent, viscous, semi solid preparation intended for external application to skin or mucous membranes. Ointment may be medicated or not..Applied to mucous membrane or skinUses Emollient Application for active ingredients to the skin OcclusiveSlide9

OINTMENTS (cont.)Oleaginous BasesAbsorption BasesWater-Removable BasesWater-Soluble BasesOintment Bases are classified based on their composition and physical C

haracteristics.

are classified based on their water solubilityHydrophobic ointmentHydophilic ointmentWater-emulsifying ointmentare classified based on their therapeutic activity and penetration to skinEpidermic

ointmentEndodermic ointment

Diadermic ointmentSlide10

CLASSIFICATION OF BASESSlide11

I. OLEAGINOUS BASESThese bases consists of oils and fats (hydrophobic). The most important are the Hydrocarbons i.e. petrolatum, paraffins and mineral oils.The combination of these materials can produce a product of desired melting point and viscosity.They ae highly compatible, occlusive and good emollients(a) Petrolatum (Soft paraffin)This is a purified mixture of semi-solid hydrocarbons obtained from petroleum or heavy lubricating oil.Yellow soft paraffin (Petrolatum; Petroleum jelly)This a purified mixture of semisolid hydrocarbons obtained from petroleum. It may contain suitable stabilizers like, antioxidants e.g. a-tocopherol (Vitamin E), butylated hydroxy toluene (BHT) etc. Melting range : 38 to 560C.White soft paraffin (White petroleum jelly, White petrolatum)This a purified mixture of semisolid hydrocarbons obtained from petroleum, and wholly or partially decolorized by percolating the yellow soft paraffin through freshly burned bone black or adsorptive clays

. Melting range : 38 to 560C.Slide12

(b) Hard paraffin (Paraffin)

This is a mixture of solid hydrocarbons obtained from petroleum.

It is colorless or white, odorless, translucent, wax-like substance. It solidifies between 50 and 570C and is used to stiffen ointment bases.

(c) Liquid paraffin (Liquid petrolatum,; White mineral oil)It is a mixture of liquid , hydrocarbons obtained from petroleum. It is transparent,

colourless, odourless, viscous liquid.

On long storage it may oxidize to produce peroxides and therefore, it may contain tocopherol

as

antioxidants.

It is used along with hard paraffin and soft paraffin to get a desired consistency of the ointment. Tubes for eye, rectal and nasal ointments have nozzles with narrow orifices through which it is difficult to expel very viscous ointments without the risk of bursting the tube. To facilitate the extrusion

upto

25% of the base may be replaced by liquid

paraffins

.Slide13

Advantages of hydrocarbons bases:

(i)     They are not absorbed by the skin. They remain on the surface as an occlusive layer that restricts the loss of moisture hence, keeps the skin soft.

(ii)   They are sticky hence ensures prolonged contact between skin and medicament.(iii) They are almost inert. They consist largely of saturated hydrocarbons, therefore, very few incompatibilities and little tendency of rancidity are there.(iv)  They can withstand heat sterilization, hence, sterile ophthalmic ointments can be prepared with it.(v)   They are readily available and cheap.Slide14

Disadvantages of hydrocarbon bases;(i)     It may lead to water logging followed by maceration of the skin if applied for a prolonged period.(ii)   It retains body heat, which may produce an uncomfortable feeling of warmth.(iii) They are immiscible with water; as a result rubbing onto the surface and removal after treatment both are difficult.(iv)  they are sticky, hence makes application unpleasant and leads to contamination of clothes.(v)   Water absorption capacity is very low, hence, these bases are poor in absorbing exudate from moist lesions.Slide15

II. ABSORPTION

BASE

The term absorption base is used to denote the water absorbing or emulsifying property of these bases and not to describe their action on the skin.These bases (some times called emulsifiable ointment bases) are generally

anhydrous water insoluble and water unwashable

.

Preparations

of this type do not contain water as a component of their basic formula but if water is incorporated a W/O emulsion results.

Wool Fat (anhydrous lanolin)

It is the purified anhydrous fat like substance obtained from the wool of sheep

.

·      Slide16

  It is practically insoluble in water but can absorb water upto 50% of its own weight. Therefore it is used in ointments the proportion of water or aqueous liquids to be incorporated in hydrocarbon base is too large.·        Due to its sticky nature it is not used alone but is used along with other bases in the preparation of a number of ointments.e.g. Simple ointment B.P. contains 5% and the B.P. eye ointment base contains 10% woolfat.Hydrous Wool Fat (Lanolin)·        It is a mixture of 70 % w/w wool fat and 30 % w/w purified water. It is a w/o emulsion. Aqueous liquids can be emulsified with it.·        It is used alone as an emollient.·        Example:- Hydrous Wool Fat Ointment B.P.C

Beeswax

It is purified wax, obtained from honey comb of bees.It contains small amount of cholesterol. It is of two types: (a) yellow beeswax and (b) white beeswax.Slide17

Advantages of absorption bases:(i)      They are less occlusive nevertheless, are good emollient.(ii)   They assist oil soluble medicaments to penetrate the skin.(iii)

 They are easier to spread.

(iv)  They are compatible with majority of the medicaments.(v)   They are relatively heat stable.

(vi)

  The base may be used in their anhydrous form or in emulsified form.

(vii)They can absorb a large quantity of water or aqueous substances.

Disadvantages

: 

Inspite

of their hydrophilic nature, absorption bases are difficult to wash.Slide18

III. Water removable base

A-WATER

MISCIBLE BASES Emulsion Base)1-They are miscible with an excess of water.

2-Ointments

made from water-miscible bases are easily removed after use.

3-O/w emulsion

4- can be diluted with water

5- can be used to absorbed exudate (discharge) from skin lesion.

There

are three official anhydrous water-miscible ointment bases:-

Example:-           

Emulsifying ointment B.P.   

-

 contains anionic emulsifier.

Cetrimide

emulsifying ointment B.P.      - contains cationic emulsifier

Cetomacrogol

emulsifying ointment B.P.      - contains non-ionic emulsifier

W/O

EMULSION BASE

O/W EMULSION BASE

Hydrous

Hydrous

Will absorb water

Will absorb water

Insoluble in water

Insoluble in water

Not washable

washableSlide19

e.g. Hydrophilic ointment sodium lauryl sulfate 1% emulsifying agent steryl alcohol 25% emulsifying ointment while petrolatum 25% oleaginous base PEG 12% aqueous phase water 37% aqueous phase

Advantages of water miscible bases:

(i)     Readily miscible with the exudates from lesions.(ii)   Reduced interference with normal skin function.(iii) Good contact with the skin, because of their surfactant content.(iv)  High cosmetic acceptability, hence there is less likelihood of the patients discontinuing treatment.(v)   Easy removal from the hair.Slide20

B. WATER

SOLUBLE BASES

Water soluble bases contain only the water soluble ingredients and not the fats or other greasy substances, hence, they are known as grease-less bases.Water soluble bases consists of water  soluble ingredients such as polyethylene glycol polymers (PEG) which are popularly known as “carbowaxes” and commercially known as “

macrogols”.

Unlike water miscible ointment contain no

olegenous

baase

Like

water miscible ointment

are washable

Water soluble, water washable non

greasable

The

PEGs are mixtures of

polycondensation

products of ethylene and water and they are described by numbers representing their average molecular weights. Like the paraffin hydrocarbons they vary in consistency from viscous liquids to waxy solids.

Example:-

Macrogols

200, 300, 400             

-

 viscous liquids

Macrogols

1500                           

-

 greasy semi-solids

Macrogols

1540, 3000, 4000, 6000  

-

 waxy solids.

Different PEGs are mixed to get an ointment of desired consistency

.Slide21

Advantages of PEGs as ointment base:(a)    They are water soluble; hence, very easily can be removed from the skin and readily miscible with tissue exudates.(b)   Helps in good absorption by the skin.(c)    Good solvent properties. Some water-soluble dermatological drugs, such as salicylic acid, sulfonamides, sulfur etc. are soluble in this bases.(d)   Non-greasy.(e)    They do not hydrolyze, rancidify or support microbial growth.

(f)    Compatibility with many dermatological medicaments.

Disadvantages:(a)    Limited uptake of water. Macrogols dissolve when the proportion of water reaches about 5%.

(b)   Reduction in activity of certain antibacterial agents, e.g. phenols,

hydroxybenzoates

and quaternary compounds.

(c)    Solvent action on polyethylene and bakelite containers and closures.Slide22

EXAMPLES of basesOleaginous Bases

Absorption Bases

Emulsion Bases

Water Soluble BasesSlide23

Oleaginous BasesAbsorption BasesWater-Removable BasesWater-Soluble BasesOintment Bases are classified based on their composition and physical Characteristics.are classified based on their water solubilityHydrophobic ointmentHydophilic ointment

Water-emulsifying ointment

are classified based on their therapeutic activity and penetration to skinEpidermic ointmentEndodermic ointmentDiadermic ointmentSlide24

Hydrophobic ointments: oleaginous base (hydrocarbon)Hydrophobic (lipophilic) ointments are usually anhydrous and can absorb only small amounts of water. Typical bases used for their formulation are water-insoluble hydrocarbons such as hard, soft and liquid paraffin, vegetable oil, animal fats, waxes, synthetic glycerides and polyalkylsiloxanes. Water-emulsifying ointments: w/o emulsion – water absorption baseo/w emulsion- water miscible baseWater-emulsifying ointments can absorb large amounts of water. They typically consist of a hydrophobic fatty base in which a w/o agent, such as wool fat, wool alcohols, sorbitan esters, mono glycerides, or fatty alcohols can be incorporated to render them hydrophilic. They may also be w/o emulsions that allow additional quantities of aqueous solutions to be incorporated. Such ointments are used especially when formulating aqueous liquids or solutions. Hydrophilic ointments: water soluble base (PEG-macrogol)Hydrophilic ointment bases are miscible with water. The bases are usually mixture of liquid and solid polyethylene glycols (

macrogols)

Ointment further classified based on their water solubilitySlide25

Classification of ointments According to their therapeutic properties based on penetration of skin. (a) Epidermic, (b) Endodermic, (c) Diadermic(a) Epidermic ointmentsThese ointments are intended to produce their action on the surface of the skin and produce local effect.

They are not absorbed.They acts as protectives, antiseptics and parasiticides.(

b) Endodermic ointmentsThese ointments are intended to release the medicaments that penetrate into the skin. They are partially absorbed and acts as emollients, stimulants and local irritants.(c) Diadermic ointmentsThese ointments are intended to release the medicaments that pass through the skin and produce systemic effects.Slide26

Oleaginous Ointment BasesAbsorption Oint. BasesWater-absorption

Oil/Water Emulsion Oint.Bases

Water-misicbleWater-miscible Ointment BasesWater soluble

Composition

oleaginous compounds

oleaginous base + w/o surfactant

oleaginous base + water (> 45% w/w) + o/w surfactant (HLB

>

9)

Polyethylene Glycols (PEGs)

Water Content

anhydrous

anhydrous

hydrous

anhydrous

, hydrous

Affinity for Water

hydrophobic

hydrophilic

hydrophilic

hydrophilic

Spreadability

difficult

difficult

easy

moderate to easy

Washability

nonwashable

nonwashable

washable

washableSlide27

Stabilityoils poor; hydrocarbons betteroils poor; hydrocarbons betterunstable, especially alkali soaps and natural colloids; nonionics betterstable

Drug Incorporation Potential

solids or oils (oil solubles only)solids, oils, and aqueous solutions (small amounts)solid and aqueous solutions (small amounts)solid and aqueous solutionsDrug Release Potential*poor

poor, but > oleaginousfair to good

good

Occlusiveness

yes

yes

no

noSlide28

Usesprotectants, emollients (+/-), vehicles for hydrolyzable drugs

protectants, emollients (+/-), vehicles for aqueous solutions, solids, and non-hydrolyzable drugs

emollients, vehicles for solid, liquid, or non-hydrolyzable drugsdrug vehiclesExamples

White Petrolatum, White Ointment

Hydrophilic Petrolatum, Anhydrous Lanolin, Aquabase™,

Aquaphor

®,

Polysorb

®

Hydrophilic Ointment,

Dermabase

™,

Velvachol

®,

Unibase

®

PEG Ointment,

Polybase

™Slide29

Selection of the Appropriate Base

The condition of the patient's skin, e.g. oozing or dry

The rule in dermatology that

if a patient's skin is dry-wet it, If it is wet-dry it

if a patient's skin is dry, occlusive ointment base that retain moisture is preferable

The selection of the base of an ointment depends on many factors:

Patient FactorsSlide30

Physicochemical Factors

The desired release rate of the drug from the ointment base

The desired enhancement of the percutaneous absorption

of the drug

The desired occlusion of moisture from the skin by the base

The stability of the drug in the ointment base, for a drug that

hydrolyzes rapidly as antibiotics, a hydrocarbon base would

provide the greatest stability

The influence of the drug on the consistency of the ointment

base

1

2

3

4

5Slide31
Slide32

Routes of skin PenetrationInclude transport via:

1-

Hair follicles and sebaceous glands 2- Sweat glands

1

2

These routes avoid penetration through the stratum

corneum

and therefore known as

shunt routes

.

The Transappendageal route:

There are two diffusional routes to penetrate intact skin:Slide33

1

2

Although these routes offer high permeability, they are of

minor importance because of their relatively small area,

0.1% of the total skin area.

The

transappendageal

route seems to be most important for

ions and large

polar molecules which hardly permeate through the stratum

corneum

.Slide34

Transepidermal transport means that molecules cross the intact horny layer stratum corneum

The

transepidermal

route :Slide35

Two potential micro-routes are existing *The transcellular (intracellular) rout *The intercellular pathways

The principal pathway taken by drugs is decided by its partition coefficient

Hydrophilic drugs partition into the intracellular (Transcellular)

pathways, whereas lipophilic drugs traverse the stratum

corneum

via the intercellular route.Slide36

Factors Affecting Percutaneous Absorption Factors concerning the

nature of the drug

Factors concerning the nature of the vehicle Factors concerning the condition of the skin

Percutaneous absorption

is the absorption of substances from outside the skin to positions beneath the skin, including entrance into the blood stream.Slide37

1.

Drug concentration Percutaneous absorption

Drug partition coefficient (greater attraction to the skin than to the vehicle) Percutaneous absorption

Molecular weight below 800

Percutaneous absorption

Particle Size

Percutaneous absorption

5. Solubility in mineral oil and water

Percutaneous absorption

Factors concerning the nature of the drug Slide38

1.

Spreadability of the vehicle Percutaneous absorption2. Mixing with the sebum

Percutaneous absorption

3.

Hydration of the skin Percutaneous absorption

Oleaginous vehicles

act as moisture barriers through which the sweat from the skin cannot pass, thus increased hydration of the skin beneath the vehicle and increase Percutaneous absorption.

Factors concerning the nature of the vehicleSlide39

Factors concerning the condition of the skin

Transdermal absorption follow

Fick’s First Law of DiffusionJs = Km D Cs E

Js

= Flux of solute through the skin.

Km = Distribution coefficient of drug between

vehicle

and

stratum

corneum

.

D = Membrane Diffusion coefficient for drug in stratum

corneum

.

Cs = Concentration difference of solute across the

membrane.

E = Thickness of stratum

corneum

. Slide40

1.

The thickness stratum

corneum Percutaneous absorption

2. Multiple application dosing

Percutaneous absorption than single Application

3.

Time of contact with the skin

Percutaneous absorption

4.

Broken skin permit (remove of the stratum

corneum

)

Percutaneous absorptionSlide41

creamsCreams are homogeneous, semi-solid preparations consisting of opaque emulsion systems. Consistency depends on the type of emulsion whether the cream is W/O or O/W, and on the nature of the solids in the internal phase. Creams are intended for the application to the skin or certain mucous membranes for protective, therapeutic, or prophylactic purposes, especially where an occlusive effect is not necessary.Slide42
Slide43
Slide44

Pastes are homogeneous, semi-solid preparations containing high concentrations of insoluble powdered substances (usually not less than 20%) dispersed in a suitable base. The pastes are usually less greasy, more absorptive, and stiffer in consistency than ointments because of the large quantity of powdered ingredients

presentFor example teeth pasteSlide45

Gels and Jellies Gels are semi solid system in which liquid phase is constrained With a 3-d polymeric matrix having a high degree of physical Or

chemical cross linking by means of gelling agentJellies

are transparent or translucent non greasy semisolid and contain more water than gels.Example of gelling agent; Gelatin, agar, pectin, tragacanth form gels by this mechanismSlide46

Poultices(Cataplasma) It is a soft mass of vegetable constituents or clay, usually heated before application. They are solid or semisolid masses of solid matter applied to skin in order to Reduce inflammation and in some cases to act as a counter irritant.After

heating the preparation is spread on dressing and applied to the affected area of the skin.

Kaolin poultice BP is prepared by mixing and heating dried, heavy kaolin and boric acid with glycerin. The product is spread on a dressing and applied hot to the skin.Slide47

Plasters Plasters are solid or semi solid masses made by incorporating medicaments in the resinous or waxy bases which are melted or spread on suitable baking material..They are generally used to,Afford protection and medicinal support.Slide48

composition of semi solid dosage form Ingredients used in preparation of semi solid dosage form:Active pharmaceutical ingredientsBases PreservativesHumectants Anti oxidantsEmulsifierGelling agent

Permeation enhancerBuffersSlide49

BasesIt is one of the most important ingredient used in the formulation of semisolid dosage formOintments (oleaginous base, absorption base, water soluble base, water miscible base)Cream (w/o emulsion, o/w emulsion)Gel, should contained polymeric matrix

Plaster- should contain resin (waxy material)Slide50

Presevatives Some bases , although, resist microbial attackCommonly used preservative include: Methyl hydroxy benzoate

Benzoic acid Slide51

AntioxidantTo prevent hydrolysis of active ingredient.Example : Butylated hydroxy toluene (BHT) vitamin _ESlide52

EMULFISIERS:Quaternary ammonium compounds (cetrimide)Slide53

Gelling agentsGelling agent forms a gel dissolves in a liquid phase as a colloid mixture that forms a weakly cohesive internal structure.Example of gelling agent; Gelatin, agar, pectin, tragacanth form gels by this mechanismSlide54

Permeation enhancerSkin can acts as a barrier with the introduction of various panetration enhancers, panetration of the drug through the skin can be improved. For example – methanol. Slide55

Humectants A humectant is a hygroscopic substance . For example glycerinSlide56

Buffers Buffers are added to variopus purpose such as: Compatibility with skin

Drug solubility Drug Stability

Influence on ionization of drugExample: Sodium acetate , Sodium CitrateSlide57

Methods of preparationSlide58

PREPARATION OF SEMI SOLIDSTrituration methodFusion methodChemical reaction method

Emulsification method

Ex. Ointments

creams

pastes

Ex. Ointments

creams

pastes

Ex. Ointments

creams

Ex. Ointments

creams

(Ointments, creams, pastes)Slide59

Remington: The Science and Practice of PharmacyPharmaceutics: The Science of Dosage Form Design by AultonAnsel's Pharmaceutical Dosage Forms and Drug Delivery SystemsREFRENCESSlide60

http://ijpsr.com/bft-article/recent-advances-in-semisolid-dosage-form/?view=fulltexthttp://4my5151.blogspot.com/2013/12/chapter-6.html?m=1https://www.slideshare.net/mobile/rababambreen1/semisolid-dosage-formhttps://www.slideshare.net/mobile/docmano15/semi-solid-dosage-formsSlide61

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