Gels are transparent semisolid preparations meant for external application to the skin or mucous membrane. They consist of either a suspension of small inorganic particles or large organic molecules in a liquid vehicle that appea…
Pastes are semisolid preparations for external application containing a high proportion of finely powdered medicaments. They are stiffer and are usually employed for their protective action and for their ability to absorb serous …
(i) Pastes generally contain a large amount (50%) of finely powdered solids. So they are often stiffer than ointments. (ii) When applied to the skin pastes adhere well, forming a thick coating protects and soothes inflamed and…
An emulsion system contains an oil phase, an aqueous phase, and an emulsifying agent. For o/w emulsion systems, the following emulsifying agents are used: (i) Water-soluble soap (ii) Cetyl alcohol (iii) Glyceryl mono…
Chemical reactions were involved in the preparation of several famous ointments in the past, e.g., the Strong Mercuric Nitrate Ointment of 1959 B.P.C. (a) Ointment containing free iodine Iodine is only slightly soluble in …
This method applies in the base or a liquid in small amounts. (i) Solids are finely powdered and are passed through a sieve (#250, #180, #125). (ii) The powder is taken on an ointment slab and triturated with a small amoun…
When an ointment base contains several solid ingredients such as white beeswax, cetyl alcohol, stearyl alcohol, stearic acid, hard paraffin, etc. as base components, it is required to melt them. The melting can be done in two…
The skin itself has two main layers, the epidermis, which is the outermost layer of the skin, covers the dermis and is the active part of the skin, holding the hair muscles, blood supply, sebaceous glands, and nerve receptors. Th…
1. Ointments: Ointments are semisolid preparations meant for external application to the skin or mucous membrane. They usually contain a medicament or medicaments dissolved, suspended, or emulsified in the base. 2. Creams: C…
Definition: Semi-solid dosage forms are dermatological preparations intended to be applied externally on the skin to produce local or systemic effects e.g. ointments, creams, gels, and pastes. They contain one or more active ing…