Water-soluble ointments

Melt the stearyl alcohol and white petrolatum (steam bath) and warm to about 75°C. Heat the water to 75°C and add the sodium lauryl sulfate, propylene glycol, methylparaben, and propylparaben. Add the aqueous phase and stir until congealed. IV. Water-soluble ointment (polyethylene glycol ointment, USP 14) Polyethylene glycol 4000 (Carbowax 4000) 50%... 

Hydrogel and water-soluble ointment achieve their consistency by means of different gel-forming agents (gelatin, methylcellulose, polyethylene glycol). Lotions are aqueous suspensions of water-insoluble and solid constituents. 

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. 

IV. Water-soluble ointment (polyethylene glycol ointment, USP 14)... 

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. 

Yellow mercuric oxide may be obtained by precipitation from solutions of practically any water-soluble mercuric salt through the addition of alkah. The most economical are mercuric chloride or nitrate. Although yellow HgO has some medicinal value in ointments and other such preparations, the primary use is as a raw material for other mercury compounds, eg, Millon s ha.se[12529-66-7], Hg2NOH, which is formed by the reaction of aqueous ammonia and yellow mercuric oxide. 

In experiments with water-soluble inhibitors, the subsample was stirred under nitrogen during post-addition of an aqueous solution of the inhibitor followed by an aqueous sodium nitrite solution. Aliquots were weighed into 1-oz ointment jars, covered with nitrogen, sealed, and stored at 37 for later replicate analyses. Preparation of the positive control subsample was identical except that water was added in place of inhibitor. 

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. 

In most cases, ointments, suppositories, ophthalmic, and parenteral products assume the color of their ingredients and do not contain color additives. In addition to esthetics and the certification status of a dye, a formulation pharmacist must select the dyes to be used in a particular formula on the basis of the physical and chemical properties of the dyes available. Of prime importance is the solubility of a prospective dye in the vehicle to be used for a liquid formulation or in a solvent to be employed during a pharmaceutical process (such as when the dye is sprayed on a batch of tablets). In general, most dyes are broadly grouped into those that are water-soluble and those that are oil-soluble few, if any, dyes are both. 

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. 

Water-removable ointments and creams are basically hydrophilic-type emulsions. They are prepared by fusion followed by mechanical addition approach. Hydrocarbon components are melted together and added to the aqueous phase that contains water-soluble components with constant stirring until the mixture congeals. A hydrophilic emulsifying agent is included in the aqueous phase in order to obtain stable oil-in-water dispersion. Sodium lauryl sulfate is used in the preparation of hydrophilic ointment USP. 

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

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. 

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. 

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. 

The prodrug approach described above also can be used to alter the solubility characteristics, which, in turn, can increase the flexibility in formulating dosage forms. The solubility of methylprcdnisolonc can be altered from essentially water-insoluble methylpredni.solone acetate to slightly water-insoluble methylprednisolone to water-soluble meth-ylprednisolone. sodium succinate. The water-soluble sodium hemisuccinate salt is used in oral, intravenous, and intramuscular dosage forms. Methylprednisolone itself is normally found in tablels. The acetate ester is found in topical ointments and sterile aqueous suspensions for intramuscular injection. Both the succinate and acetate esters are hydrolyzed to the active methylprednisolone by the patient s own systemic hydrolytic enzymes (esterases). 

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