Ointment formulation

Sahcyhc acid USP, EP, and other pharmacopeia grades are used medically as antiseptic, disinfectant, antifungal, and keratolytic agents. Sahcyhc acid is formulated in lotion or ointment formulations for the treatment of dandmff, eczema, psoriasis, and various parasitic skin diseases. Because the keratolytic property of this aromatic acid has use in the safe removal of dead skin cells from the surface of healthy skin, the acid is used in concentrated sahcyhc acid solutions or suspensions to remove warts and corns. In more dilute form, sahcyhc acid preparations have found use in dandmff and eczema treatment. Sahcyhc acid has been considered and found effective by the Advisory Committees to the FDA in various over-the-counter (OTC) dmg regulated uses. Among these are acne products, dermatitis, dry skin, dandmff and psoriasis products, and foot care products (24). 

A variety of formulations of salicylic acid have been used as peeling agents. These include 50% ointment formulations (Table 6.1) [2,3], as well as 10, 20 and 30% ethanol formulations (Table 6.2) [4,6]. More recently, commercial formulations of salicylic acid have become available (BioGlan Pharmaceuticals Company, Malvern, PA Bionet Esthetics, Little Rock, AR). 

Because anthralin exerts its clinical effects at low cellular concentrations, therapy usually starts with low concentrations (0.1% to 0.25%) with gradual increases to higher concentrations (0.5% to 1%). Cream and ointment formulations are usually applied in the evening and allowed to remain overnight. 

Segers JD, Zatz JL, Shah VP. 1997. In vitro release of phenol from ointment formulations. Pharm Technol 21 70-76, 80-81. 

Transdermal delivery of certain APIs is now common for the treatment of some medical conditions, and there are several excipients that are promoted as transdermal penetration enhancers. One of the earlier materials developed was laurocapram (Azone ). There is a detrimental interaction between laurocapram and mineral oil (liquid paraffin) whereby when both are included in the same formulation, the skin penetration-enhancing properties of laurocapram are lost. Such interactions have implications for extemporaneous mixing of different cream and ointment formulations in the pharmacy. 

As another example, desonide and parabens in cream and ointment formulations were cleaned up by SPE by first testing mixtures of hexane-chloroform with silica, diol, and aminopropyl sorbents [36]. The solvent combination of 20% chloroform in hexane was found to be the optimum for dissolving the ointment base and yielding high recoveries of the analytes. The silica and aminopropyl sorbents were found to give nearly identical quantitative results, whereas the diol sorbent gave lower recoveries. Table 2.4 outlines the solvent considerations needed to elute retained compounds on silica and C,8 sorbents. 

R. A. Kenley, S. Chandry, and G. C. Visor, An automated columnswitching HPLC method for analyzing active and excipient materials in both cream and ointment formulations, Drug Dev. Ind. Pharm., 4 1781 (1985). 

Masuda et al. have reported the supercritical fluid chromatography of retinol palmitate and tocopherol acetate using an octadecylsilyl silica gel column with ethanol-modified carbon dioide as the mobile phase [43]. Both retinol and tocophenol eluted within 5 min. The method was applied to the determination of these compounds in an ointment formulation. The method was found to be linear for both retinol and tocophenol from 0.5 to... 

Nook, T.H., In vivo measurement of the keratolytic effect of salicylic acid in three ointment formulations. Br. J. Dermatol., 1987, 117 243-5. 

Once the ointment has been instilled, the bioavailability of subsequently instilled solutions may be altered because the solution is blocked from contact with the ocular surfece. Whenever both solution and ointment formulations are used in therapy, the solution should be instilled before the ointment is applied. 

The clinical effectiveness of 40% glucose is comparable with that of 5% sodium chloride. Because it is difficult to maintain sterility of the solution unless a preservative is added, a commercial preparation containing 40% glucose may often contain preservatives and is available in ointment formulation (see Table 15-1). 

Weller PJ, Newman CM, Middleton KR, Wicker SM. Stability of a novel dithranol ointment formulation, containing ascorbyl palmitate as an anti-oxidant. / Clin Pharm Ther 1990 15 419 23. 

De Muynck C, Lalljie SPD, Sandra P, et al. Chemical and physicochemical characterization of petrolatums used in eye ointment formulations. / Pharm Pharmacol 1993 45 500—503. 

Polyoxyethylene stearates are particularly useful as emulsifying agents when astringent salts or other strong electrolytes are present. They can also be blended with other surfactants to obtain any hydrophilic-lipophilic balance for lotions or ointment formulations. See Table III. 

Starch is also used in topical preparations for example, it is widely used in dusting powders for its absorbency, and is used as a protective covering in ointment formulations applied to the skin. Starch mucilage has also been applied to the skin as an emollient, has formed the base of some enemas, and has been used in the treatment of iodine poisoning. 

Anthralin traditionally was formulated in stiff paste bases to provide adherence to plaques. Subsequently, cream and ointment formulations have been developed that are more cosmetically appealing and appear to be equivalent in efficacy. Usually it is applied in the evening and allowed to remain overnight. 

The bacitracin zinc and polymyxin B sulfate ophthalmic ointment USP is a sterile antimicrobial ointment formulated for ophthalmic use. Bacitracin zinc is the zinc salt of bacitracin, a mixture of related cyclic polypeptides (mainly bacitracin A) produced by the growth of an organism of the lichenlformis group of Bacillus subtilis var Tracy. It has a potency of not less than 40 bacitracin units per milligram. Polymyxin B sulfate is the sulfate salt of... 

All items are blended uniformly together to produce an ointment formulation having a pH of 7.9. The carbopol is neutralized using item 5. 

The lubricating ointments are composed of a mixture of white petrolatum, mineral oil, liquid or alcohol lanolin, and sometimes a preservative. These highly viscous formulations cause considerable blurring of vision, and consequently they are used primarily at bedtime, in critically ill patients, or in very severe dry-eye conditions. Such aqueous and ointment formulations are only fair substitutes for the precorneal tear film, which is truly a poorly understood lipid, aqueous, and mucin trilaminar barrier. 

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