Ointments physical properties

Many attempts to alter the physical properties of neomycin by the formation of various salts have been described. Thus the neomycin salts of the higher fatty acids, such as the stearate, palmitate and myristate3(3 31 were prepared and being water-insoluble were formulated in ointment bases. Similarly, the undecylenate salt has been prepared and processes for its production patented3 33 34 The undecylenate and caprylate salts have been described as being particularly suitable as antimitotic compounds35. 

Also, it is used in lotions, ointments, cosmetics, and as a topical antiseptic. Physical Properties... 

However, the proportions of paraffin, petrolatum, and mineral oil may be varied to produce an ointment of the desired physical properties. 

In contrast to more established spectroscopic techniques, SS-NMR spectra are virtually independent of the physical properties of the sample, such as particle size, homogeneity, or residual water content. Therefore, pharmaceutical solids can be studied by NMR without a need for special sample preparations. Samples viable for SS-NMR analysis include a whole range of pharmaceutical formulations such as tablets, lyophilized powders, capsules, suspensions, and ointments. SS-NMR does not suffer from a preferred orientation restriction, which often leads to an incorrect identification of polymorphs when using XRPD. In addition, SS-NMR is a nondestructive technique that allows other analyses to be performed on the same sample after the NMR spectrum is acquired. 

The particle size of active constituents suspended in pharmaceutical ointments for topical and particularly ophthalmic use needs to be rigorously controlled. Often sufficiently fine material can only be obtained by micronisation (fluid energy milling), Whilst this process achieves a very fine particle size (<5 im), it can also lead to serious aggregation of the active. Adequate comminution and subsequent successful dispersion of the micronised drug will depend on its physical properties the nature of the ointment base used, and the energy imparted during the dispersion process. 

A comprehensive characterisation of the batches was conducted in an attempt to establish which physical properties correlated with good dispersion. A cross correlation analysis was performed on the data. This only demonstrated correlation where it may have been expected, notably between sets of particle size data. There was some association between the surface area data of the batches and their appearance as assessed by Scanning Electron Microscopy. Otherwise the surface area data did not correlate with either the particle size data or with the ability to form acceptable ointments. The surface area data reflects the porous nature of the material, since a reduction in particle size does not markedly affect the specific surface. 

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. 

Today, for the most part, readers, critics, and audiences who turn to the plays examined in this book—many of which have become fundamental parts of what we understand as our cultural canon— do not think the way their authors and original audiences did. We tend either to brush over their powerfully physical terminology, or to understand it figuratively, as colorful turns of phrase, dead metaphors. Yet the plays themselves offer an antidote to this reading. The worlds they present, steeped in medicines, ointments, drugs, paints, and poisons, insist that words, plays, and selves are all material, tangible, embodied presences. If we look at them as they ask to be looked at, we can still find that they have this virtuous property to make us see as we were wont to see. 

Absorption of substances from outside the skin to positions beneath the skin, including entrance into the blood stream, is referred to as percutaneous absorption. This is shovm in Figure 2.5. The absorption of a medicament present in a dermatological such as a liquid, gel, ointment, cream, paste, among others depends not only on the physical and chemical properties of the medicament but also on its behavior in the vehicle in which it is placed and upon the skin conditions. The vehicle influences the rate and degree of penetration, which varies with different drugs and vehicles. 

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