Influence of some hydrophilic polymers on dissolution characteristics of furosemide through solid dispersion: An unsatisfied attempt for immediate release formulation

Abstract

Background: The objective of the present investigation was to enhance dissolution
characteristics of water insoluble drug, furosemide (FRMD), by solid dispersion in
various hydrophilic carriers. Materials and Methods: The solid dispersions were
prepared by solvent evaporation technique using urea and Hydroxy Propyl Methyl
Cellulose (HPMC E50 LV). Physical mixtures of drug with above-mentioned polymers
were also prepared. Phase solubility studies were performed for drug in the presence of
excipients in different ratios. The formulations were evaluated for drug content, in vitro
dissolution, Fourier transform infrared (FT-IR) and differential scanning calorimetry
(DSC). Similarity factor (f2) was calculated for comparison between dissolution of
pure drug and drug–polymer physical mixtures with solid dispersions. Results: Phase
solubility studies indicated linear increase in the drug solubility with increase in carrier
concentration. In vitro release studies revealed that dissolution characteristic of FRMD
was improved by solid dispersion technique. All the preparations of FRMD exhibited
significant improvement in its dissolution profiles. Solid dispersion of FRMD with
HPMC E50 LV exhibited the highest rate and extent of dissolution. Optimized
batches of solid dispersions of both the carriers were characterized by FT-IR and DSC
analysis, which indicated absence of major interactions between FRMD and carriers.
Conclusion: Solid dispersion technique is one of the finest techniques to improve
dissolution of poorly soluble drugs.