Sodium alginate as a potential carrier in solid dispersion formulations to enhance dissolution rate and apparent water solubility of BCS II drugs

• Sodium alginate was used as a potential carrier in solid dispersions.
• The solid dispersions were characterized by DSC, XRPD, FTIR, Raman and SEM.
• The solid dispersions successfully improved the drug aqueous solubility up to 16.7-fold.
• The solid dispersions achieved promising dissolution rates releasing more than 80% of drug in the SD.
• SA acted as good anti plasticizer agent preventing the drug crystallization for 90 days.

The solid dispersion technique is the most effective method for improving the dissolution rate of poorly water-soluble drugs, however it depends on a suitable carrier selection. The work explored the use of the biopolymer sodium alginate (SA) as a potential carrier in solid dispersions (SD). The data demonstrated that SA was able to improve the biopharmaceutical properties of the BCS II drug telmisartan (TEL) of low solubility even using relative small drug:polymer ratio. A solid state grinding process was used to prepare the solid dispersions (SD) during 45 min. The SD were prepared in different proportions of drug and carrier of 1:1, 1:3, 1:5, 1:7 and 1:9 (mass/mass). DSC, XRPD, FTIR and Raman confirmed the presence of molecular interactions between TEL and the carrier. FTIR supports the presence of hydrogen bonds between TEL and the carrier. SD_1:5, SD_1:7 and SD_1:9 enhanced the dissolution rate of the drug releasing more than 80% of the drug in just 30 min (83%, 84% and 87%). The the t-test results demonstrated equal dissolution efficiency values for SD_1:7 and Micardis®, however the similarity (f2) and difference (f1) fit factors showed that the SD and Micardis® are statistically different. The physical stability studies demonstrated that SD using sodium alginate as a carrier remained unchanged during the period of 90 days at room temperature, showing that the sodium alginate acts as a good anti plasticizer agent, preventing the drug recrystallization.