Ointments stability

Uses Solubilizer for fragrances emulsifier for w/o cosmetic creams and lotions, hairdressings, pharmaceutical ointments stabilizer and aux, emulsifier for o/w systems... 

As a pharmaceutical, methyl salicylate is used in liniments and ointments for the relief of pain and for rheumatic conditions. As a flavor and fragrance agent, it is used in confectioneries, dentifrices, cosmetics, and perfumes. Other commercial applications for methyl salicylate are as a dye carrier, as a uv-light stabilizer in acrylic resins, and as a chemical intermediate. The May 1996 price was 5.50/kg (18). 

The stability of suspensions, emulsions, creams, and ointments is dealt with in other chapters. The unique characteristics of solid-state decomposition processes have been described in reviews by D. C. Monkhouse [79,80] and in the monograph on drug stability by J. T. Carstensen [81]. Baitalow et al. have applied an unconventional approach to the kinetic analysis of solid-state reactions [82], The recently published monograph on solid-state chemistry of drugs also treats this topic in great detail [83],... 

Behind the relatively straightforward compositional nature of ophthalmic solutions, suspensions, and ointments, however, lie many of the same physicochemical parameters that affect drug stability, safety, and efficacy, as they do for most other drug products. But additionally, specialized dosage forms present the ophthalmic product designer with some extraordinary compositional and manufacturing challenges. These... 

Simone and Popino have considered the stability of neomycin in both hydrophobic and hydrophilic ointment bases. No loss of potency over a period of 1 year at 20°C was reported for formulations containing carboxymethylcellulose, polyethylene glycol(P.E.G.) or white-soft paraffin. However, formulations containing hydrous lanolin were reported to be unstable. All materials used in the formulations were obtained from U.S. sources. Coates et al3°l investigated the use of P.E.G. from British sources and described neomycin as being incompatible with the materials tested. 

Topical liquids, ointment, creams a. Microbial limit test, TAMC, TCYMC only b. USP AET for various use A < 0.75 test development, scale-up and validation batches only A > 0.75 all batches on stability for microbial limit first three batches for AET a. b. 0, 6, 12, 24, 36 months 0, middle of stability period and expiry... 

Ophthalmic ointments and solutions Sterility test, CCI, AET Test all batches on stability with the exception of the first three batches for AE 0, 12, 24, 36 months... 

The inclusion of the a routine microbial limit test in a marketed product stability protocol depends on the pharmaceutical dosage form. Typically, the test would be used only for nonsterile products, especially oral liquids, nasal sprays, and topical liquids, lotions, and creams that have sufficient water activity to support the growth of microorganisms. In contrast, tablets, powder- and liquid-filled capsules, topical ointments, vaginal and rectal suppositories, nonaqueous liquids and inhalation aerosols with a water activity too low to allow for the product to support the growth of microorganisms would not be routinely tested. 

Rectal Avoids problems of stability in gastrointestinal tract No first-pass metabolism Useful if oral administration is not possible Unpopular Inconvenient Erratic absorption Irritation Suppositories, enemas (solutions, suspensions, emulsions), foams, ointments, creams... 

These drug products are usually solutions marketed in a LDPE bottle with a dropper built into the neck (sometimes referred to as droptainer) or ointments marketed in a metal tube with an ophthalmic tip. A few solution products use a glass container because of stability concerns... 

Nitroglycerin was marketed for a while in an ointment form for application to the forearm surface. The ointment consisted of a base of petrolatum, the drug, and lactose, which increased the drug s stability and reduced its explosiveness. If it was applied to another body part or another person, there could be some very unpleasant side effects. 

Ointment with cliquinol TLC Add acetone, warm on steam bath, filter with pledget glass wool Silica Benzene-MeOH (9 1) 254 nm USP23. p. 1113 HPLC [10,581,776,908] stability [1104] [ ]... 

T. Sat, Y. Saito, K. Yamaoka, and M. Nishikawa, Stability test of prednisolone in ointment by high-speed liquid chromatography, Yakuzaigaku, 39 20 (1979). 

T. A. Bierimer, N. Asral, and J. A. Albanese, Simultaneous, stability-indicating capillary gas chromatographic assay for benzo-caine and the two principal benzyl esters of Balsam Peru formulated in a topical ointment, J. Chromatogr., 623 395 (1992). 

Kuriyama, K. et al., Vitamin E ointment at high dose levels suppresses contact dermatitis in rats by stabilizing keratinocytes, Inflamm. Res., 51, 483, 2002. 

Benzylpenicillin is incompatible with rubber products and metal ions. Stability is affected by alcohols, surfactants, oxidizing and reducing agents, macrogols and other hydroxy compounds, glycerol, glycols, some paraffins and ointment bases, preservatives such as chlorocresol or thiomersal, blood and blood products, and antibacterials such as amphotericin, cephalosporins, and vancomycin. Injections of benzylpenicillins and aminoglycosides should be administered separately. 

Selection of an appropriate base for an ointment or cream formulation depends on the type of activity desired (e.g., topical or percutaneous absorption), compatibility with other components, physicochemical and microbial stability of the product, ease of manufacture, pourability and spreadability of the formulation, duration of contact, chances of hypersensitivity reactions, and ease of washing from the site of application. In addition, bases that are used in ophthalmic preparations should be nonirritating and should soften at body temperatures. White petrolatum and liquid petrolatum are generally used in ophthalmic preparations. Table 1 summarizes... 

Combinations of bases are sometimes used to acquire better stability. Gelling agents such as carbomers and PEG are also included in some ointment and cream preparations. Table 3 shows examples of cream bases used in some commercial cream preparations. 

Packaging An ideal container should protect the product from the external atmosphere such as heat, humidity, and particulates, be nonreactive with the product components, and be easy to use, light in weight, and economic [14]. As tubes made of aluminum and plastic meet most of these qualities, they are extensively used for packaging semisolids. Aluminum tubes with special internal epoxy coatings are commercially available for improving the compatibility and stability of products. Various modified plastic materials are used for making ointment tubes. Tubes made... 

Gels are relatively easier to prepare compare to ointments and creams. In addition to the gelling agent, medicated gels contain drug, antimicrobial preservatives, stabilizers, dispersing agents, and permeation enhancers. Some of the factors discussed below are essential to obtain a uniform gel preparation. 

Emulsion A dosage form consisting of a two-phase system comprised of at least two immiscible liquids, one of which is dispersed as droplets (internal or dispersed phase) within the other liquid (external or continuous phase), generally stabilized with one or more emulsifying agents. (Note Emulsion is used as a dosage form term unless a more specific term is applicable, e.g. cream, lotion, ointment.). 

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