Solid Dispersion of Hydroxypropyl β‐Cyclodextrin and Ketorolac: Enhancement of In‐vitro Dissolution Rates, Improvement in Anti‐inflammatory Activity and Reduction in Ulcerogenicity in Rats

Ketorolac, is a non-steroidal anti-inflammatory drug, with strong analgesic activity. It is practically insoluble in water and has been implicated in causing gastrointestinal ulceration. This study describes the formulation of solid dispersions of ketorolac using hydroxypropyl β-cyclodextrin (HPβ-CyD) and β-cyclodextin (β-CyD) as carriers, to improve the aqueous solubility of the drug, thus enhancing its bioavailability. Also, reduction in ulcerogenicity was anticipated. Differential scanning calorimetry and X-ray diffraction studies indicated loss of crystalline nature of the drug, in the dispersions prepared with HPβ-CyD. NMR studies revealed a strong interaction between drug and HPβ-CyD. Solid dispersions of drug with β-CyD retained the crystalline nature of the drug. All the solid dispersions showed a remarkable improvement in the rate and extent of dissolution of ketorolac. The kneaded dispersion with HPβ-CyD prepared using a 1: 1 alcohol—water mixture showed promise in reducing the ulcer-inducing effect of ketorolac in rats. Oral administration of this dispersion was found to inhibit carrageenan-induced paw oedema in rats to a significantly greater extent compared with ketorolac or its trometamol salt. Though β-CyD as a carrier for ketorolac gave faster release of the poorly soluble drug, HPβ-CyD proved to be superior to β-CyD, as a carrier in the kneaded dispersion prepared using 1: 1 alcohol—water mixture. These results suggest that solid dispersions of ketorolac with HPβ-CyD aid in faster dissolution and better bioavailability of the drug. The higher solubility of the drug in the presence of HPβ-CyD also reduces local gastrointestinal side-effects of the drug.