Semi Solds

Question 1

What are the semi sold pharmaceutical form

Answer 1

Ointments, creams and gels

Question 2

Where can we apply semisolids

Answer 2

The skin, eye, nasally, vaginally and rectally

Question 3

Why do we use unmedicated ointments

Answer 3

Un-medicated ones are used for their physical effects as protectants, emollients, or lubricants.

Question 4

What are topical applications can be designed for

Answer 4

Local effects,
Systemic absorption

Question 5

How are topical applications designed

Answer 5

Designed to deliver drug into the skin in treating dermal disorders, with the skin as the target organ.

Question 6

What are transdermal projects

Answer 6

designed to deliver drug
through the skin (percutaneous absorption) to
the general circulation for systemic effects, with
the skin not being the target orga

Question 7

What are ointments

Answer 7

semisolid preparations intended for
external application to the skin or mucous
membranes.
 Could be medicated or un-medicated.

Question 8

What are the different ointment bases

Answer 8

1. Oleaginous bases
2. Absorption bases
3. Water-removable bases
4. Water-soluble bases

Question 9

Why do we use oleaginous bases

Answer 9

– On application on the skin, they have an emollient
effect and they protect against the escape of
moisture.

– They are effective as occlusive dressings as they
can remain on the skin for long periods of times
without drying out and they are immiscible with
water and are difficult to wash off.

Question 10

What are some examples on oleaginous bases

Answer 10

petrolatum, white petrolatum, white
ointment, and yellow ointment.

Question 11

Can we incorporate water/aqueous preparations in oleaginous bases

Answer 11

only in small amounts and with some difficulty.

Question 12

What is petroleum USP

Answer 12

– It is a purified mixture of semisolid
hydrocarbons obtained from petroleum.
– It varies in color from yellowish to light amber.
– It melts at 36 – 60 C.
– Also known as yellow petrolatum or petroleum
jelly.
– Commercial product: Vaseline.

Question 13

What is white petroleum

Answer 13

It is a purified mixture of semisolid
hydrocarbons obtained from petroleum than
has been wholly or nearly decolorized.
– It is used for the same purpose as petrolatum.
Because of its light color, it is considered
more esthetically pleasing by some patients
and pharmacists.
– Also known as white petroleum jelly.
– Commercial product: white Vaseline.

Question 14

What is yellow ointment

Answer 14

– Yellow wax is the purified wax obtained form the
honeycomb of the bee Apis mellifera.
– also called simple ointment.
– It has a slightly greater viscosity than plain petrolatum

Question 15

How do we prepare yellow ointment

Answer 15

– It has the following formula:
Yellow wax 50 g
Petrolatum 950 g
.
– It is prepared by
• Melting the yellow wax on a water bath
• Adding the petrolatum until the mixture is uniform
• Cooling and stirring until congealed.

Question 16

What is white ointment

Answer 16

Differs from yellow ointment by substitution of
white wax (bleached yellow wax) and white
petrolatum in the formula.

Question 17

What are the two types of absorption bases

Answer 17

 Those that permit the incorporation of aqueous
solutions resulting in the formation of w/o
emulsions (e.g., hydrophilic petrolatum)
.
 Those that are w/o emulsions (also known as
emulsion bases) that permit the incorporation of
additional quantities of aqueous solutions (e.g.,
lanolin)

Question 18

Why are absorption bases hard to remove from the skin

Answer 18

the external phase of the
emulsion is oleaginous

Question 19

What are absorption bases used for

Answer 19

useful for incorporation of small volumes
of aqueous solutions into hydrocarbon bases.

 first, incorporate the aqueous solution into the
absorption base then, incorporate the mixture into
the hydrocarbon base.

Question 20

What are some examples for absorption bases

Answer 20

Hydrophilic petrolatum
Lanolin

Question 21

How do we use hydrophilic petrolatum

Answer 21

– It has the following formula:
Cholesterol 30 g
Stearyl alcohol 30 g
White wax 80 g
White petrolatum 860 g
– It is prepared by:
• Melt the stearyl alcohol and white wax on a steam bath
• Add the cholesterol with stirring until dissolved
• Add the white petrolatum
• Allow the mixture to cool while stirring until congealed.

Question 22

What are the commercial products for hydrophilic petrolatum

Answer 22

Commercial product: Aquaphor  has the capacity to
absorb up to three times it weight in water

Question 23

What is lanolin

Answer 23

Obtained from the wool of sheep.
– It is a wax-like substance that has been
cleaned, deodorized and decolorized.
– It contains not more than 0.25% of water.
Additional water may be incorporated into
lanolin by mixing.

Question 24

What are water removable bases

Answer 24

– They are o/w emulsions
– Can be easily washed from the skin with
water (often called water washable bases).
– They may be diluted with water or aqueous
solutions.
– They can absorb serous discharges.
– Hydrophilic Ointment, USP, is an example of
this type of base.

Question 25

What are water soluble bases

Answer 25

They do not contain oleaginous components. – They are completely water washable and often referred to as greaseless. – They can not incorporate large amount of aqueous solutions  they become very soft. – They mostly are used for incorporation of solid substances. Example: Polyethylene glycol ointment, USP.

Question 26

How does the physical state of PEG changes

Answer 26

Depending on the average molecular weight: –PEG < 600: clear colorless liquid –600 < PEG < 1000: semisolid. –PEG > 1000: wax-like white material

Question 27

How can we use the appropriate base

Answer 27

– Desired release rate of the drug substance from the ointment base. – Desirability of topical or percutaneous drug absorption. – Desirability of occlusion of moisture from the skin. – Stability of the drug in the ointment base. – Effect, if any, of the drug on the consistency or other features of the ointment base. – Desire for a base easily removed by washing with water – Characteristics of the surface to which it is applied

Question 28

Give examples on conditions with the right base

Answer 28

– An ointment is generally applied to dry, scaly skin. – A cream is applied to weeping or oozing surfaces – A lotion is applied to intertriginous areas or where friction may occur, as between the thighs or under the armpit

Question 29

What is incorporation

Answer 29

The components are mixed until a uniform preparation is obtained. • In extemporaneous compounding (small scale): the pharmacist often use a spatula to rub the ingredients together on an ointment slab

Question 30

How can we incorporate solids

Answer 30

– When preparing an ointment by spatulation  the pharmacist works the ointment with a stainless steel spatula having a long, broad blade. – He would periodically removes the accumulation of ointment on the large spatula with a smaller one. – A metal spatula is always used unless one of the components reacts with metal (e.g., Iodine), then a hard rubber spatula should be used.

Question 31

What are the steps for soild incorporation

Answer 31

• Place all solid material in a mortar • Grind and blend the solid powders thoroughly. • Transfer the powder to one side of the ointment slab. • Place the ointment base on the other side of the slab. • Mix one portion of the powder with a portion of the base until uniform • Continue mixing in a geometric dilution fashion till the powder and the ointment base in thoroughly and uniformly blended.

Question 32

When shouldn't we use a metal spatula

Answer 32

components reacts with metal (e.g., Iodine), then a hard rubber spatula should be used.

Question 33

What is levigation

Answer 33

mixing the solid material with a vehicle in which it is insoluble to make smooth dispersion (while wet)

Question 34

Name some levigation agents

Answer 34

• Mineral oil when for oleaginous bases. • Glycerin for hydrophilic bases. • Or a small portion of ointment/cream base itself

Question 35

How much levigation agent should we add

Answer 35

About equal volume to the solid material.

Question 36

Where to levigate and what are the advantages

Answer 36

– Where to levigate? In a mortar with a pestle or directly on the ointment slab with a spatula. – Advantages: reduction of particle size + dispersion of the powder.

Question 37

Consider the following case: – You have solids (could be the drug or some additives) that you want to incorporate in the ointment/cream where: • They are soluble in a common solvent. • The solvent will affect neither the stability of the drug nor the efficacy of the product.

Answer 37

You may first dissolve them in that solvent (e.g., water or alcohol) • The solution is added to the ointment base by spatulation or in a mortar and pestle.

Question 38

Why do we use mortar and pestle for larger volumes

Answer 38

because the liquid is more captive than on an ointment slab.

Question 39

How do we incorporate gummy materials

Answer 39

– Place the crystals on the middle of the ointment slab – Add few drops of alcohol or isopropyl alcohol to dissolve the crystals with a spatula. – Spread the solution on the slab and allow it t evaporate. – Scrub the thin film from the slab with the spatula and incorporate the powder material into the ointment base.

Question 40

How doe we incorporate methanol and camphor

Answer 40

• Place both of the crystalline materials on the middle of the ointment slab • Rub them against each other with pressure using a metal spatula. • This will form an eutectic mixture with a melting point below room temperature  crystals will melt and form a liquid oily mixture on the slab. • Incoporate this oily liquid with a portion of the base and continue mixing till all the liquid is absorbed by the b

Question 41

How can we incorporate liquids

Answer 41

– Can be added to the ointment after careful consideration of the ointment base’s capacity to accept the volume of liquid required. – Aqueous solution may be incorporated into hydrophobic bases (e.g., petrolatum) by using an absorption base (e.g., aquaphor) or a hydrophilic base (e.g., hydrophilic ointment, USP). – Nevertheless, the capacity of hydrophilic bases are limited and high quantity of liquid will result in an ointment that is too soft or semi-liquid. – Alcoholic solutions of small volume may be added easily to oleaginous bases or emulsion bases.

Question 42

How can we use roller mills

Answer 42

can be used to force coarsely formed ointments through stainless steel or ceramic rollers. – This will produce ointments uniform in composition and smooth in texture

Question 43

What is the Fusion method

Answer 43

All or some of the components of the ointment are combined by being melted together then cooled with continuous stirring until congealed. Components that are not melted are added to the congealing mixture as it is being cooled Heat-labile substances and volatile components should be added last, when the temperature of the mixture is low enough not to cause any decomposition or volatilization

Question 44

How can we conduct the Fusion method on a small scale

Answer 44

porcelain dish or glass beaker

Question 45

What ointment bases needs the Fusion method and why

Answer 45

– Beeswax – Paraffin – Stearyl alcohol – High molecular weight PEG Because they don’t lend themselves well to mixture by incorporation..

Question 46

What is the melting procedure

Answer 46

A. The material with the highest melting points should be heated to the lowest required temperature to produce a melt. B. The materials with the lowest meting point is melted first then, the remaining components are added in order of their melting points (form low to high) under slow increase of temperature  fusion of all components is achieved at lower temperature than would be expected for the highest melting point component due to solvent action exerted by the first melted components on the others. C. For preparation of ointments having an emulsion base  the method of manufacture involves both melting and emulsification.

Question 47

How can we prepare ointments with the Fusion method

Answer 47

 The water-immiscible components such as the oil and waxes are melted together in a steam bath (70 – 75 C).  Meantime, an aqueous solution of the heat stable, water soluble components is prepared and heated to the same temperature as the oleaginous phase.  Add the aqueous solution slowly with continuous stirring to the melted oleaginous mixture.  Maintain the temperature for 5-10 minutes then cool the mixture with continuous stirring until congealed.

Question 48

What are creams

Answer 48

They are semisolid preparation containing one or more medicinal agents dispersed in either a w/o emulsion or o/w emulsion or in any other type of water-washable base.

Question 49

Why are creams preferred

Answer 49

• Creams are preferred over ointments because they are easier to spread and remove.

Question 50

What are pastes

Answer 50

Pastes are semisolid preparations intended for application to the skin. They generally contain a larger proportion of solid material (such as 25%) than ointments and therefore are stiffer.

Question 51

How can we prepare pastes

Answer 51

• Pastes can be prepared in the same manner as ointments, by direct mixing or the use of heat to soften the base prior to incorporating the solids

Question 52

Name 2 properties of pastes

Answer 52

• Because of the stiffness of pastes, they remain in place after application and are effectively employed to absorb serous secretions. • Because of their stiffness and impenetrability, pastes are not suited for application to hairy parts of the body

Question 53

Give an example for pastes

Answer 53

• Among the few pastes in use today is zinc oxide paste , which is prepared by mixing 25% each of zinc oxide and starch with white petrolatum. • The product is very firm and is better able to protect the skin and absorb secretions than is zinc oxide ointmen

Question 54

What are the types of packaging for semisolids

Answer 54

• Large-mouth ointment jars • Metal or plastic tubes.

Question 55

How should we store ointments

Answer 55

• Ointments should be stored in a closed containers to prevent against microbial contamination. • Ointments should be stored in a cool place to avoid product separation by heat.

Question 56

What are the sizes of the tubes

Answer 56

• Topical preparations are usually frequently packaged in 5, 15, and 30 g tubes. • Ophthalmic ointments are typically packaged in 3.5 g tubes.

Question 57

How can we fill ointments in a jar

Answer 57

– On a small scale in the pharmacy, ointments jars can be filled by carefully transferring the weight amount of ointment into the jar with a spatula. – The jar size should be selected so that the ointment reach near the top of the jar but not so high as to touch the lid when closed. – Ointments prepared by fusion may be poured directly into the jar to congeal in it.

Question 58

What does then penetration of the skin depends on

Answer 58

– The physicochemical properties of the drug. – The characteristics of the pharmaceutical vehicle. – The condition of the skin (broken versus unbroken)

Question 59

What are the layers of the skin

Answer 59

The skin is divided histologically into – The stratum corneum (the outer layer, part of the epidermis) – The living epidermis – The dermis

Question 60

What is the stratum corneum

Answer 60

The stratum corneum is 10 – 15 m of flat, partially desiccated, dead epidermal cells. • The stratum corneum is composed of 40 % protein (mainly keratin) 40% water 20 % lipids: triglycerides, free fatty acids, cholesterol and phospholipids.

Question 61

• Hair follicles and gland ducts can provide entry for drug molecules. But because their relative surface area is so minute compared to the total epidermis, they are minor factors in drug absorption. • The stratum corneum being a keratinized tissue, behaves as a semi-permeable membrane, and drug molecules can penetrate by passive diffusion.

Answer 61

Ok

Question 62

What does the rate of drug movement through the startum comeum depends on

Answer 62

– Drug concentration in the vehicle. – The aqueous and lipid solubility of the drug – The distribution coefficient of the drug between the stratum corneum and the drug vehicle.

Question 63

What do bases vary in

Answer 63

– Emollient and occlusive effects. – Ease of application of the product – Ease of removal of the product.

Question 64

 Oleaginous bases: provide higher emollient and occlusive effects.  Creams (o/w emulsions): spread more easily and easier to remove.  Water-soluble bases: non greasy and easily removed.

Answer 64

Ok