Utility of the hyperbranched polymer Hybrane S1200 for production of instant-release particles by hot melt extrusion

Particles composed of 90:10 or 80:20 mixtures of the hyperbranched poly(esteramide) Hybrane S1200 and the poorly water-soluble drug hydrochlorothiazide were produced by hot melt extrusion at maximum temperatures of 90°C without any need for addition of a plasticizer. In dissolution rate assays in USP 29 apparatus II, particles of the smallest size category (<250 µm) containing 10% of hydrochlorothiazide released 95% of their load within 5 min. This fast release is attributed to the combination of the high solubility of Hybrane S1200, the dispersion of the drug in non-crystalline form in the polymer matrix (attested to by the results of powder X-ray diffractometry, and scanning electron microscopy), and to the fact that the main interaction between drug and polymer is through hydrogen bonds (attested to by ATR-IR difference spectra).