Ointment water-soluble bases

Ointments are semisolid preparations that are intended for external use. Ointments may contain either finely powdered drugs or their mixtures, liquids, and other drug forms incorporated into appropriate bases. They are applied to the skin for their physical effects as emollients (which make the skin more pliable), protectants, lubricants, and drying agents. Ointment bases are also used as vehicles in which to incorporate topical medications which exert specific effect. There are four types of ointment bases, namely, oleaginous, absorption, water removable, and water soluble bases. 

Water-soluble bases do not contain any oily or oleaginous phase. Solids can be easily incorporated into these bases. They may be completely removed from the skin due to their water solubility. Polyethylene glycol (PEG) ointment National Formulary (NF) is an example of a water-soluble base. 

Ointments Hydrocarbon (oily), adsorptive water-washable, or water-soluble bases emulsifying agents, glycols, medicating agent External... 

Ointments utilize certain bases that act as vehicles to deliver the drug and to impart emollient and lubricant properties to the preparation. Usually, but not always, they contain medicinal substances. Properties of ointments may vary from product to product depending on their specific use, ease, and extent of application. In general, ointment bases may be classified into four general groups hydrocarbon, absorption, water-removable, and water-soluble bases. 

Ointment An unctuous semisolid for topical application. Typical ointments are based on petrolatum. An ointment does not contain sufficient water to separate into a second phase at room temperature. Water soluble ointments may be formulated with polyethylene glycol. 

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. 

This ester-type anesthetic is poorly absorbed. Because it contains benzocaine, which has a low water solubility, it is prepared in a base containing petrolatum and sodium carboxymethylcellulose. Eugenol is included for its antiseptic and anodyne properties. Hydroxy-quinoline sulfate is a preservative. This ointment can be directly applied to abraded or ulcerated lesions with minimal systemic effects. It is sometimes used to temporarily relieve denture sores and painful lesions. 

The results of incorporating pilocarpine (V) (a relatively water-soluble dmg) and fluoro-metholone (a lipophilic dmg) into a water-inoil ointment base can be compared in Fig. 9.36. Pilocarpine is thought to be released only when in contact with aqueous tear fluid, whereas the steroid, being soluble in the base, can diffuse through the base to replenish the surface concentrations and thus produce a sustained effect. 

Use Water-soluble lubricants solvents for dyes, resins, proteins plasticizers for casein and gelatin compositions, glues, zein, cork, and special printing inks solvent and ointment bases for cosmetics and pharmaceuticals intermediates for nonionic surfactants and alkyd resins. 

USE As water-soluble lubricants for rubber molds, textile fibers, and metal-forming operations. In food and food packaging. In hair prepns, in cosmetics in general. Pharmaceutic aid (ointment and suppository base). As a stationary phase in gas chromatography. Also in water paints, paper coatings, polishes and in the ceramics industry. Caution Solvent action on some plasticsl... 

A semisolid triglyceride (Softisan 378 ) that meets the monograph Hard fat Ph. Eur. may establish the option to prepare not only eye creams with water-soluble active substances but also solution-t3q)e eye ointments and eye creams with active substances soluble in fatty oils (i.e. clotrimazole, ciclosporin). Softisan 378 shows delayed solidification when molten and drawn into a S3Tinge, thus making membrane filtration (<0.2 pm pore size) possible at about 30 °C. However, specific formulas of triglyceride-based eye ointments and creams have not been fully developed yet. For example the ratio Softisan 378 )/ refined peanut oil or the optimum cholesterol concentration as an emulsifier stiU has to be investigated. 

R. K. Sharma et al.. Evaluation of some insect repellent formulations. Part I. Water soluble ointment Q6 bases, Indian Journal of Hospital Pharmacy, 21, 26, 1984. 

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