Lubricant incompatible

Lubricants incompatible with the polymer must act as external lubricants or glidants. They become enriched on the external surfaces of the flow units and reduce the interunit friction. The reduced friction prevents the formation... 

Mold Release /Lubricant - incompatibility with all binder components - viscosity lower than primary component... 

Use chemical interaction matrices to identify potential incompatibilities between combinations of materials (not just binary reactions) and interactions with cleaning solvents, heat transfer fluids and other utilities, equipment lubricants, scrubbing media, materials of construction, etc. Implement management of change procedures for changes in design, operation, equipment and chemistry. 

Incorrect lubrication can take many forms. One example is the use of oil that is too thick or too thin, or is incompatible with the metal of the gears. Others include unsuitable methods of application, bad filtration, inadequate maintenance, filling to the wrong level, and poor standards of storage and handling. 

It cannot be emphasized too strongly that dirt and correct lubrication are incompatible. The lubricant manufacturer has a comprehensive system of classification, filtration and inspection of packages, which ensures that all oils and greases leaving his plant are free from liquid and solid contaminants. It is in his own interests that the user should take the same care to ensure that the lubricant enters his machinery in as clean a condition as that in the bulk tank or barrel. The entry of abrasive dust, water and other undesirable matter into bearings and oilways may result if lubricants are handled carelessly. 

Incompatibilities have also been observed in solid dosage forms. A typical tablet contain binders, disin-tegrants, lubricants and fillers. Compatibility screening for a new drug should consider two or more excipients from each class. Serajuddin et al. have developed a drug-excipient compatibility screening model to predict interactions of drug substances with excipients [49],... 

It was recognized quite some time ago that DTA analysis could be used to deduce the compatibility between a drug substance and its excipients in a formulation. The effect of lubricants on performance was as problematic then as it is now, and DTA proved to be a powerful method in the evaluation of possible incompatibilities. Jacobson and Reier used DTA to study the interaction between various penicillins and stearic acid [17]. For instance, the addition of 5% stearic acid to sodium oxacillin monohydrate completely obliterated the thermal events associated with the antibiotic. Since that time, many workers employed DTA analysis in the study of drug-excipient interactions, although the DTA method has been largely replaced by differential scanning calorimetry technology. 

Three properties that contribute the most to migration are (1) incompatibility with the resin, (2) low melt point, and (3) low molecular weight. Examples of noncolorant additives that are prone to migrate are (1) lubricants/dispersants such as metal stearates and bis-stearamides, (2) mold release and slip agents, and (3) antistatic agents. All of these ingredients serve useful purposes in color formulations. If you exceed their solubility limit in the end-use resin, however, you risk blooming and its consequences. 

Lubricants have been classified as either internal or external. Typically, internal lubricants have meant materials that are compatible with PVC that promote flow. The difference between internal lubricants and plasticiser is that the internal lubricant is only soluble at high temperature whereas the plasticiser is soluble and functional at room temperature. External lubricants on the other hand, are said to be incompatible and come to the surface and create metal release. It is reported that there are two distinct types of external lubricants. Internal lubricant efficiency can be readily predicted by simple mathematical formula and that partial substitution of esters for paraffin allows the reduction of modifier or increased filler levels to achieve savings without loss of any physical properties. 

Process aids do not usually contribute to the performance of the dosage form in terms of quality or in vivo performance. Indeed, lubricants, because of their hydrophobic nature, can hinder disintegration and dissolution of solid dosage forms unless the level and mode of incorporation is carefully characterized and controlled. Thus, in addition to drug-excipient interactions, the potential for interexcipient competition and incompatibility must be considered and studied. 

Differential scanning calorimetry experiments with some directly compressible tablet excipients suggests that aspartame is incompatible with dibasic calcium phosphate and also with the lubricant magnesium stearate. Reactions between aspartame and sugar alcohols are also known. 

Sodium stearyl fumarate is supplied in a pure form and is often of value when the less pure stearate-type lubricants are unsuitable owing to chemical incompatibility. Sodium stearyl fumarate is less hydrophobic than magnesium stearate or stearic acid and has a less retardant effect on tablet dissolution than magnesium stearate. A specification for sodium stearyl fumarate is contained in the Food Ghemicals Godex (FGC). 

Surfactants were one excipient family which required reevaluation in HFAs. Surfactants are used in MDIs for several reasons seal lubrication, emulsification, dispersion, solubilization, and as a preservative. Surfactants used in GFG formulations such as lecithin, sorbitan trioleate, soya lecithin, and oleic acid are highly soluble in GFG propellants (particularly GFG 11), however in HFA propellants, the solubility of these surfactants is relatively poor. Several authors point out that surfactant polarity, indicated by their respective hydrophilic-lipophilic balance (HLB) correlates with the incompatibility of the aforementioned surfactants... 

During the 1990s there was a marked increase in problems arising from complex aromatic asphaltenic species in fuel and their incompatibility in predominantly paraffinic lubricants. This marine black paint phenomenon led to progressively darker and more tenacious surface coatings, especially in rocker boxes and crankcases. Lubricant suppliers resolved this by altering the balance of detergents used in trunk piston oils. 

Overuse of lubrication including mixing incompatible greases. 

Finally it should be noted that certain restrictions may have to be incorporated into the packaging material specification, e.g. No lubricants to be used , (magnesium and zinc stearate or similar lubricants may be incompatible with either the drug substance or certain excipients). 

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