Dissolution media

Other aqueous dissolution media, such as H2S0ip H3P01, and HC1, should also be further investigated. Masking agents which could be used to control the corrosive nature of these alternate dissolution media to stainless steel process equipment should also be studied. 

Dissolution media, aqueous—See also Aqueous media and Aqueous processing... 

When the relative flux is 1, reaction of the basic species with the acid does not contribute to the dissolution of HA since the concentration of B is too low relative to the saturated solubility of HA to impact the dissolution rate (CB < Cha )-As the concentration of the basic species in bulk increases (CB CHa ), the relative flux will approximately double and the reaction of B with HA will begin to dominate the dissolution process. The utility and elegance of Eq. (8) is that one can estimate the increase in dissolution of an acid due to reaction with a base by simply knowing the base concentration in the dissolution media and the... 

The accelerated dissolution of soluble pure acidic or basic drugs, through the addition of acidic or basic components to the dissolution media, becomes significant when the concentration of added components approaches the intrinsic solubility of the drug. 

Surfactants added to dissolution media of insoluble drugs may produce dissolution results which are more indicative of the in vivo fed state than of the fasted state. 

JR Crison, ND Weiner, GL Amidon. Dissolution media for in vitro testing of water-insoluble drugs Effect of surfactant purity on in vitro dissolution of carbama-zepine in aqueous solutions of sodium lauryl sulfate. J Pharm Sci 86 384-388, 1997. 

Figure 14 Diltiazem HC1 release versus time from core I devices containing 100 mL of NaCl 360 mg of diltiazem HC1 with dissolution media of pH 1.2 and 8.0. The data from the separate media are superimposable. (From Ref. 24.)...

P. E. Luner, D. V. Kamp. Wetting behavior of bile salt-lipid dispersions and dissolution media patterned after intestinal fluids. J. Pharm. Sci. 2001,... 

The second situation when IVIVC is not likely for class II drugs is where the absorption is limited by the saturation solubility in the gastrointestinal tract rather than the dissolution rate, as discussed in more detail above. In this situation, the drug concentration in the gastrointestinal tract will be close to the saturation solubility, and changes of the dissolution rate will not affect the plasma concentrationtime profile and in vivo bioavailability. Standard in vitro dissolution tests are carried out under sink conditions , i.e., at concentrations well below the saturation solubility. Thus, only effects related to dissolution rate can be predicted in vitro. If more physiologically relevant dissolution media are used, which do not necessarily provide sink conditions , the possibility for IVIVC could be improved, as has been indicated by the results of recent studies using simulated intestinal medium [76],... 

In a bioanalytical method, analyses of blank samples (plasma, urine, or other matrix) should be obtained from at least six sources. Each blank sample should be tested for the possible interference of endogenous substances, metabolites, or degradation products. The response of the peaks interfering at the retention time of the analyte should be less than 20% of the response of a lower quantitation limit standard, and should be less than 5% of the response of the internal standard that was used [18, 19]. For dissolution studies, the dissolution media or excipients should not give a peak or spot that has an identical Rt or Rf value with the analyte [20]. 

The flow-through cell is applicable not only for the determination of the dissolution rate of tablets and sugar-coated tablets, but has also been applied to suppositories, soft-gelatin capsules, semisolids, powders, granules, and implants. A small volume cell containing the sample solution is subjected to a continuous stream of dissolution media. The dissolution... 

Galia E, Nicolaides E, Horter D, Lobenberg R, Reppas C, Dressman JB. Evaluation of various dissolution media for predicting in vivo performance of class I and II drugs. Pharm. Res 1998 15 698-705. 

The Schmidt number is the ratio of kinematic viscosity to molecular diffusivity. Considering liquids in general and dissolution media in particular, the values for the kinematic viscosity usually exceed those for diffusion coefficients by a factor of 103 to 104. Thus, Prandtl or Schmidt numbers of about 103 are usually obtained. Subsequently, and in contrast to the classical concept of the boundary layer, Re numbers of magnitude of about Re > 0.01 are sufficient to generate Peclet numbers greater than 1 and to justify the hydrodynamic boundary layer concept for particle-liquid dissolution systems (Re Pr = Pe). It can be shown that [(9), term 10.15, nomenclature adapted]... 

Marques M. Dissolution Media Simulating Fasted and Fed States. Dissolution Technol 2004 11 16. 

Therefore, the development and validation of a scientifically sound dissolution method requires the selection of key method parameters that provide accurate, reproducible data that are appropriate for the intended application of the methodology. It is important to note that while more extensive dissolution methodologies may be required for bioequivalency evaluations or biowaivers (i.e., multiple media, more complex dissolution media additives, and multiple sampling time points), it is also essential for the simplified, routine quality control dissolution method to discriminate batch-to-batch differences that might affect the product s in vivo performance. 

Rohrs BR, Stelzer DJ. Deaeration techniques for dissolution media. Dissolution Technol 1995 2(2) 1, 7—8. 

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