Solubility particle size

The key parameter for any drug product is its efficacy as demonstrated in controlled clinical trials. The time and expense associated with such trials make them unsuitable as routine quality control methods. Therefore, in vitro surrogate tests are often used to assure that product quality and performance are maintained over time and in the presence of change. A variety of physical and chemical tests commonly performed on semisolid products and their components (e.g., solubility, particle size and crystalline form of the active component, viscosity, and homogeneity of the product) have historically provided reasonable evidence of consistent performance. More recently, in vitro release testing has shown promise as a means to comprehensively assure consistent delivery of the active component(s) from semisolid products. 

Particle size and particle size distribution studies are important for drugs that have low water solubility. Particle size reduction by milling to a micronized form increased the absorption of low aqueous solubility drugs such as griseofulvin, nitrofurantoin, and many steroids. Smaller particle size results in an increase in the total surface area of the particles, enhances water penetration into the particles, and increases the dissolution rates. With poorly soluble drugs, a disintegrant may be added to the formulation to ensure rapid disintegration of the tablet and release of the particles. 

Tablet properties inputs) Dose (mg) Solubility Particle size (gm) Minimum bulk density (g mU ) Tapped bulk density (g mU ) Carr s compressibility (%) Formulation 50.0 Insoluble 5.0 0.4 0.7 42.857 ...

Iron bioavailability is affected by valence state, form, solubility, particle size, and com-plexation which in turn may be affected by the food matrix. Complexation of iron has been found to have either a positive or negative effect on availability, with such compounds as ascorbic acid and fructose increasing availability and oxalates, phytates, phosphates and food fibers perhaps decreasing availability. Availability has also been shown to be directly correlated to acid solubility. We have found that acidity tends to increase ionization as well as favoring the ferrous state which has greater solubility at... 

The pharmacological activity, efficacy, and toxicity of an administered medicament may be profoundly affected by the physico-chemical properties of the drug and the drug dosage form. Thus, such parameters as solubility, particle size, diffusional characteristics, availability and rate of dissolution of the drug have been the areas emphasized in most biopharmaceutical studies. The effect of these parameters on drug absorption is the subject of this review. 

Data considered to be important for suspensions at the preformulation stage include solubility, particle size and propensity for crystal growth and chemical stability. Furthermore, during development, it will be important to have knowledge of the viscosity of the vehicle to obtain information with respect to settling of the suspended particles, syringibility and physical stability (Akers et al. 1987). In a report on the preformulation information required for suspensions, Morefield et al. (1987) investigated the relationship between the critical volume fraction as a function of pH. They noted that it is usually desirable to maximize the volume fraction of solids in order to minimize the volume of the dose . 

Bioavailability is influenced by several factors, such as drug characteristics (solubility, particle size, crystalline... 

Air/soil Evaporation rate Soil adsorption constant Vapor pressure Vapor density Octanol/water partition coefficient Solubility Particle size... 

Mercuric Oxide. Mercuric oxide[21908-53-2] HgO, is a red or yellow water-insoluble powder, rhombic in shape when viewed microscopically. The color and shade depend on particle size. The finer particles (< 5 -lm) appear yellow the coarser particles (> 8 -lm) appear redder. The product is soluble in most acids, organic and inorganic, but the yellow form, which has greater surface area, is more reactive and dissolves more readily. Mercuric oxide decomposes at 332°C and has a high (11.1) specific gravity. 

In a suspension polymerization, monomer is suspended ia water as 0.1—5 mm droplets, stabilized by protective coUoids or suspending agents. Polymerization is initiated by a monomer-soluble initiator and takes place within the monomer droplets. The water serves as both the dispersion medium and a heat-transfer agent. Particle size is controlled primarily by the rate of agitation and the concentration and type of suspending aids. The polymer is obtained as small beads of about 0.1—5 mm in diameter, which are isolated by filtration or centrifugation. 

Sohd salt, ground and packaged in several particle size grades, can be used in saturated salt brines to increase the fluid density (28). However, sized salt is most often used as a water-soluble material for bridging or sealing porous formations. At one time the sized salt systems were used primarily for completion or workover operations, but use has increased as ddU-in fluids for horizontal wells (29). 

To achieve the maximum coating opacity the opacifter particle size should be between 0.2 and 0.3 ]lni. A good opacifter should not be soluble in the vitreous system, should have a refractive index substantially different from the refractive index of the system, should be inexpensive, easily milled to a submicrometer particle size, and thermally stable at the film s firing temperature. 

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