Hydrocarbon-based semisolids

Ointments are commonly used for topical application of drugs to the eye.These vehicles are primarily mixtures of white petrolatum and liquid mineral oil with or without a water-miscible agent, such as lanolin.The mineral oil is added to the petrolatum to allow the vehicle to melt at body temperature, and the lanolin is added to the nonemulsive ointment base to absorb water. This allows for water and water-soluble drugs to be retained in the delivery system. Commercial ophthalmic ointments are derivatives of a hydrocarbon mixture of 60% petrolatum USP and 40% mineral oil USP, forming a molecular complex that is semisolid but melts at body temperature. In general, ointments are well tolerated by the ocular tissues, and when antibiotics are incorporated they are usually more stable in ointment than in solution. 

Ointments are composed mostly of fluid hydrocarbons meshed in a mafrix of higher melting solid hydrocarbons. Common examples of ointment bases include mineral oil, petrolatum, and polyethylene glycol. Creams are semisolid emulsion systems with an opaque... 

Many biosurfactants and their productive processes were patented, but only some of them were commercialized. Nowadays, some products based in biosurfactants can be found at the international market, like PD5, produeed by Pendragon Holdings, sold as an addietive for fuels based on a mixture of rhanmolipid biosurfactants and enzymes, EC-601, produced by EcoChem Organics, sold as a dispersive agent of water-insoluble hydrocarbons (rhanmolipids) and the products JBR, of Jeneil Biosurfactant, rhamnolipids in aqueous solutions with different purity degrees or in a semisolid form. 

Bitumens Another important class of oil-based products is bitumens. Bitumen is a generic term defined by ASTM as a class of black or dark-colored (solid, semisolid, or viscous) cementitious substances, natural or manufactured. Bitumens are composed principally of high-molecular-mass hydrocarbons of which asphalt, tars, pitches, and asphaltite are typical. Commercially these are produced from the destructive distillation of coal, crude oils, and other organic matter. Asphalt occurs naturally either in rock or a lake. In the United States the terms bitumen and asphalt are interchangeable, whereas in the United Kingdom asphalt is reserved for the naturally occvuring product and bitumen is the residue from crude oil distillation. It is important to note that the compatibility of various classes of bitumen with other raw materials can vary widely. This can lead, for example, to marked differences in chemical and solvent resistance of the end product. 

Uses white petrolatum is a purified mixture of semisolid hydrocarbons used as an ointment base in cosmetics leather grease and shoe polish component... 

Bituminous From the base word bitumen, a general term for various solid and semisolid hydrocarbons that are able to join together and are soluble in carbon bisulfide (e.g., asphalts). 

Mastic sealants are based upon bitumen and asphaltics, which are by-products of petroleum refining. The materials are semisolid or very viscous liquids and contain a variety of polymeric materials. Because of their hydrocarbon character, they can be expected to wet most substrates. However, because of their lack of any other functionality, they can be expected to dewet under moist conditions. This type of sealant has been used on roadways, some constmction sealing, and for pipes and marine sealants. 

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