The Application of Solid Dispersion Technique with D-mannitol to the Improvement in Oral Absorption of Triamterene

Abstract

Present paper proposes a new system to administer triamterene, a sparing potassium diuretic which presents absorption problems when administered as a free powder, due to its low solubility in water.

To increase the dissolution rate and subsequent oral bioavailability of this drug, it has been formulated as solid dispersion. This method involves preparation by the melting carrier method using D-mannitol as matrix. These systems were subjected to USP XXII dissolution rate determination. The results revealed a marked dissolution rate increase of included triamterene in solid dispersions when compared with micronized drug. Further in vivo assays have demonstrated the absorption efficiency for the proposed systems when referred to pure drug. In vitro-in vivo correlation between the parameter T_80% (from dissolution rate studies) and the pharmacokinetic one K_e, has found to be acceptable. All the results obtained make this system suited for further formulation in the pharmaceutical industry.

KEY WORDS::

• bioavailability
• dissolution rate
• D-mannitol
• solid dispersion
• triamterene