Electrospun fixed dose formulations of amlodipine besylate and valsartan

Abstract

Increasing numbers of elderly people require multi-drug therapies. One route to improve adherence rates is to prepare fixed dose combinations (FDCs), in which multiple active ingredients are loaded into a single formulation. Here, we report the use of electrospinning to prepare fast-dissolving oral FDCs containing amlodipine besylate and valsartan, two drugs prescribed as FDCs for the treatment of hypertension. Electrospun fibers were prepared loaded with one or both drugs, using polyvinylpyrrolidone as the polymer matrix. The fibers were largely cylindrical in morphology and comprise amorphous solid dispersions except with the highest loadings of amlodipine besylate. HPLC demonstrated drug entrapment efficiencies of >85% of the theoretical dose. The mats have folding endurances and thicknesses suitable for use as oral films. The amlodipine besylate-loaded systems are fast-dissolving, with >90% release obtained within 120 s. In contrast, valsartan release from its single-drug formulations took longer, ranging from 360 s to 24 min. With the FDC formulations, rapid release within 360 s was achieved when the loading was 5% w/w of each drug, but again the release time increased with drug loading. Electrospun fibers therefore have significant promise as FDCs, but the target drug and its loading need to be carefully considered.