Formulations fast-dissolving

Fast-dissolving formulations (flash-dispersing) are not primarily intended to be for buccal delivery the issue here is that they may be taken without water. This causes an important difference in performance relative to ordinary immediate-release products, especially if the drug is in suspension. If the material is swallowed dry, it may adhere to the fundus area, where the amount of shear is low. This causes a significant fraction of the material to be retained resulting in tailing of the absorption phase and an apparently decreased AUC as the material is released over several hours. 

Akiyama, Y., et al. 1996. Novel peroral dosage forms with protease inhibitory activities. 2. Design of fast dissolving poly(acrylate) and controlled dmg-releasing capsule formulations with trypsin inhibiting properties. Int J Pharm 138 13. 

Site-specific delivery will require the use of a self-locating system, typically a bioadhesive formulation, although an IVR, due to its elastomeric nature, will remain located high in the vaginal space. Conversely, for rapid distribution throughout the space, semisolid or fast-dissolving solid systems will be required. For semisolids, flow properties and viscoelastic character will be the critical determinants of their ability to spread rapidly from their point of application. 

DuraSolv is Cima s second-generation fast-dissolving/disintegrating tablet formulation and is also produced using direct compression but using higher compaction... 

Information is very limited, but the interaction seems to be established. It is not likely to occur with solid form, fast-dissolving digoxin preparations (e.g. liquid-filled capsules) or digoxin in liquid form, but only with those preparations which are slowly dissolving (i.e. some tablet formulations). A reduction in digoxin levels of one-third could result in under-digitalisation. There seems to be no information about digitoxin. 

Another study by the same workers showed that propantheline increased the digoxin serum levels of a slow-dissolving tablet formulation Orion) by 40%, but had no effect on serum digoxin levels with a fast-dissolving tablet formulation Lanoxin) In a further study, propantheline increased the AUC of digoxin from Lanoxin tablets by 24%, compared with a non-significant increase of 13% with digoxin in the form of a solution in a capsule Lanoxicaps) ... 

To improve solubility, an appropriate particle formulation with fast-dissolving additives might be tried first (see example for NOBS in Ref. 145). Alternatively or additionally, disintegrants may be used. This is described in Ref. 146 for a peroxycarboxylic acid combined with swellable polymers such as carboxymethylcellulose. On the other hand, the primary particle size of the active material prior to granulation could be considered, since smaller particles typically show a shorter dissolution time, and if residues are inevitable, are likely to be less visible. If necessary, combinations of both measures (suitable additives and small particle size) may be employed. Several examples are described for the granulation of a manganese catalyst in Ref. 147. 

C. Kaur, N. Chauhan, N. Mehta, A. Mittal, U. Baja, Release Kinetics Pattern and Formulation Development of Fast Dissolving Film of an Antihypertensive Agent, Advanced Science... 

Kulkarni AS, Deokule HA, Mane MS, Ghadge DM. Exploration of different polymers for use in the formulation of oral fast dissolving strips. J Curr Pharm Res. 2 (1) 33-35, 2010. 

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