Lecture 36: Compounding Topical Preparations

What are some examples of compounding equipment?

• Unguator

• Ointment mill

• Ointment slab

What are advantages for hydrocarbon (oleaginous) bases?

• Good emollient, protective, & occlusive properties

• Not water-washable so they stay on skin & keep incorporated medications in contact w/ skin

What are disadvantages for hydrocarbon (oleaginous) bases?

• Poor patient acceptance b/c of greasy nature

• Cannot absorb water & can absorb limited amounts of alcoholic solutions

What are the 2 subgroups of absorption bases?

1. Anhydrous absorption bases

2. W/O emulsions

   1. Classified as creams as semisolid emulsions

What are the advantages of W/O absorption bases?

• Moderately good protective, occlusive, & emollient properties

• Absorb liquids

What are the disadvantages of W/O absorption bases?

• Some bases in this group have poor patient acceptance

• Not easily removed w/ washing

• USP requires a preservative

What are the advantages of O/W emulsions?

• Absorb some water or alcohol

• If enough liquid is added, base thinks out to lotion (prev was cream)

  • Absorb 30% water w/o thinning

What are the disadvantages of O/W emulsions?

USP requires to contain preservative

What are the advantages of water-soluble bases?

• Easily removed by washing

What are the disadvantages of water-soluble bases?

• Can be irritating

• Little to no emollient properties

• Preservative is required

What are hydrogels?

2- or multiple-component systems consisting of 3-dimesional network of polymer chains & water that fills space b/w macromolecules

What are the types of hydrogels?

• Natural vs. synthetic

• Homopolymeric vs. copolymeric vs. multipolymeric

• Amorphous vs. cystalline vs. non-crystalline

What does mesh size mediate?

Drug diffusion

What are some properties of Polyacylic acid (Carbomer; Carbopol)?

• Possess shear thinning (pseudoplastic) properties

• Used as thickeners, emulsion stabilizers, gel formers, & suspending agents

What are properties of Poloxamers?

• Copolymers of polyoxyethylene & polyoxypropylene

• Nonionic triblock copolymers (A-B-A)

• Form thermoreversible gels at concentrations at 15-50% that are liquid at cool temperatures, gels at room/body temperatures

• Surfactant properties & used to increase water solubility of hydrophobic, oily substances