External preparation

2

Gel

• A semisolid emulsion or suspension

• Contains a gelling agent in sufficient quantities to impart a 3-dimensional, cross-linked matrix

• Provides a cooling sensation when applied to the skin

• Usually translucent and non-greasy

3

Paste

• A semisolid suspension

• Contains a large proportion (i.e., 20-50%) of solids finely dispersed in an aqueous or fatty vehicle

• Opaque, viscous, greasy to mildly greasy

• Adheres well to the skin, forming a protective layer

4

Lotion

• A liquid emulsion

• Generally contains a water-based vehicle with > 50% of volatiles

• Has sufficiently low viscosity that it may be poured

• Opaque and non-greasy

• Tends to evaporate rapidly with a cooling sensation when applied to the skin

5

Ointment

• A semisolid emulsion or suspension

• Generally contains > 50% of hydrocarbons or PEGs as the vehicle and < 20% of volatiles

• Opaque or translucent, viscous, greasy

• Tends not to evaporate or be absorbed when applied to the skin

6

Cream

• A semisolid emulsion or suspension

• Generally contains < 50% of hydrocarbons or PEGs as the vehicle and/or > 20% of volatiles

• Opaque, viscous, non-greasy to mildly greasy

• Tends to mostly evaporate or be absorbed when applied to the skin

• Can be hydrophilic or lipophilic

Common topical dose forms includes: Common topical dose forms includes: creams, lotions, ointments and powders.creams, lotions, ointments and powders.

• Creams: A cream is a semi-solid emulsion containing a drug. The cream is usually non-greasy.

Creams are removed with water.• Lotions: A lotion is a watery preparation

containing suspended particles. Shake all lotions before application. Gently but firmly pat the lotion on the skin. Do not rub into the skin.

Why Apply Topical Drugs:

• Clean and debride (remove) a wound

• Hydrate (add water) to the skin

• Reduce inflammation

• Relieve itching or a rash

• Provide a protection barrier to the skin

• Reduce thickening of skin

In process test (IP/BP/USP) • Uniformity of weight

• Sterility: (if applicable)• Microbial quality:

• Select a sample of 10 filled containers and remove any labeling that might be altered in weight while removing the contents of the containers.

• Clean and dry the outer surfaces of the containers and weigh each container.

• Remove quantitatively the contents from each container. If necessary, cut open the container and wash each empty container with a suitable solvent, taking care to ensure that the closure and other parts of the container are retained.

• Dry and again weight each empty container together with its parts which may have been removed.

• The difference between the two weights is the net weight of the contents of the container.

Uniformity of weight (IP)

• The average net weight of the contents of the 10 containers is not less than the labelled amount and the net weight of the contents of any single containers is not less than 91 per cent and not more than 109 per cent of the labelled amount where the labelled amount is 50 g or less,

• or not less than 95.5 per cent and not more than 104.5 per cent of the labelled amount where the labelled is more than 50 g but not more than 100g.

• If this requirement is not met, determine the net weight of the contents of 10 additional containers.

• The average net weight of the contents of the 20 containers is not less than the labelled amount, and the net weight of the contents of not more than 1 of the 20 containers is less than 91 per cent or more than 109 per cent of the labelled amount where the labelled amount is 50 g or less than 95 per cent or more than 104.5 per cent of the labelled amount is more than 50 g but not more than 100 g.

Microbial quality of preparation (IP)

• This chapter provides acceptance criteria for the microbiological quality of pharmaceutical products. They are not mandatory requirements.

• If microorganism are present in a pharmaceutical preparation, they can reduce or inactivate the therapeutic activity of the product or can adversely affect the health of the patient. Hence pharmaceutical preparation should have low bio-burden and they should not have specified microorganism which are harmful.

•

• Total viable aerobic count . Not more than 102 microorganisms (aerobic bacteria plus fungi) per g or per ml.

• Pseudomonas aeruginosa: Absent in 1 g or 1 ml.

• Staphylococcus aureus: Absent in 1 g or 1 ml.

Minimum Fill (USP)• Select a sample of 10 filled containers and remove any labeling

that might be altered in weight while removing the contents of the containers.

• Clean and dry the outer surfaces of the containers and weigh each container.

• Remove quantitatively the contents from each container. If necessary, cut open the container and wash each empty container with a suitable solvent, taking care to ensure that the closure and other parts of the container are retained.

• Dry and again weight each empty container together with its parts which may have been removed.

• The difference between the two weights is the net weight of the contents of the container.

• For containers labeled by volume, pour the contents of 10 containers into 10 suitable graduated cylinders, and allow to drain completely.

• Record the volume of the contents of each of the 10 containers.

• The average net content of the 10 containers is not less than the labeled amount, and the net content of any single container is not less than 90% of the labeled amount where the labeled amount is 60 g or 60 ml or less, or not less than 95% of the labeled amount where the labeled amount is more

• than 60 g or 60 ml but not more than 150 g or 150 ml.

• If this requirement is not met, determine the content of 20 additional containers. The average content of the 30 containers is not less than the labeled amount, and the net content of not more than 1 of the 30 containers is less than 90% of the labeled amount where the labeled amount is 60 g or 60 ml or less, or less

• than 95% of the labeled amount where the labeled amount is more than 60 g or 60 ml but not more than 150 g or 150 ml.

Uniformity of dosage form (BP)• Semi-solid preparations that are supplied either in single-dose containers that

represent 1 dose of medicinal product or in metered-dose containers, and that are intended for transdermal delivery of the active substance(s) in view of a systemic effect, comply with the test for uniformity of dosage units

• Semi-solid preparations in which the active substance(s) are dissolved comply with the test for mass variation;

• Accurately weigh the amount of liquid or semi-solid that is removed from each of 10 individual containers in conditions of normal use. If necessary, compute the equivalent volume after determining the density. Calculate the active substance content in each container from the mass of product removed from the individual containers and the result of the assay. Calculate the acceptance value.

• Semi-solid preparations in which the active substance(s) are suspended comply with the test for content uniformity.

• Assay 10 units individually using an appropriate analytical method. Carry out the assay on the amount of well-mixed material that is removed from an individual container in conditions of normal use. Express the results as delivered dose. Calculate the acceptance value

• Calculation of Acceptance Value Calculate the acceptance value (AV) as shown in content uniformity, except that the individual contents of the units are replaced with the individual estimated contents defined below. x1, x2,..., xn = Individual estimated contents of the dosage units tested;

where w1, w2,..., wn = Individual masses of the dosage units tested;

• A = Content of active substance (percentage of label claim) obtained using an appropriate analytical method (assay);

• = Mean of individual masses (w1, w2,..., wn).

•