Improved solubility and corneal permeation of PEGylated curcumin complex used for the treatment of ophthalmic bacterial infections.

Naturally occurring curcumin can be used for the treatment of corneal bacterial infections with its limitation of poor solubility. Aim of the present study was to enhance solubility and permeation of curcumin for the treatment of corneal bacterial infections. For increasing solubility, curcumin and polyethylene glycol (PEG 6000) complex (1:3) was prepared by fusion melting method. Phase solubility studies were used for the calculation of Gibbs free energy of curcumin. Central composite rotatable design (CCRD) was applied for optimization of Curcumin (CUR), PEGylated Curcumin (PEG-CUR), penetration enhancer cremophore (CR). Optimized ointments were further evaluated by mucous permeation, membrane permeability and cell toxicity studies by Transwell cell, ussing chamber and Caco-2 cells respectively. Antibacterial test was also performed by agar well diffusion method. Solubility of PEG-CUR was increased up to 93±3.2% as compared to pure curcumin and content uniformity was in the range of 95-110%. Curcumin permeation from PEG-CUR ointment was increased up to 12 folds. No toxicity of Caco-2 cells for PEG-CUR even after 24h was observed. Activity index of pure CUR, PEG-CUR ointment with or without CR against S. aureus and P. aeruginosa was 97±2.3, 96±1.6, 95±2.5% respectively. Ointment with solubility enhanced PEG-CUR and cremophore can be used as a promising tool for the treatment of corneal bacterial infections.

Calcium channel blocking activity in Desmostachya bipinnata (L.) explains its use in gut and airways disorders.

Desmostachya bipinnata, despite of its popular medicinal uses, has not been widely studied for its effect in diarrhea, indigestion, and asthma. The aim of the present investigation was to provide scientific rationale for these applications. The crude aqueous-methanolic extract of D. bipinnata (Db.Cr) was evaluated through in vivo and in vitro experiments. Db.Cr (100-500 mg/kg) protected mice against castor oil-induced diarrhea, similar to loperamide. When tested on gut preparations, Db.Cr produced an atropine-sensitive spasmogenic effect in rabbit jejunum up to 5 mg/mL, followed by a partial relaxation at 10 mg/mL. With atropine preincubation, a verapamil-like inhibitory effect was evident against spontaneous and high K(+) (80 mM)-induced contractions. The maximum stimulant effect was comparable with the acetylcholine-induced maximum contraction and was similarly reproducible in guinea pig ileum. Db.Cr inhibited carbachol (1 µM)-induced contraction in rabbit trachea but caused an atropine-sensitive accentuation of high K(+) -induced contraction at 0.003-0.3 mg/mL followed by inhibition at 1-5 mg/mL. On activity-directed fractionation, inhibitory effect was concentrated on organic and stimulant effect in aqueous fraction. This study, suggesting the presence of calcium antagonist activity, possibly underlying its medicinal effect in hyperactive gut and respiratory disorders, and cholinergic activity, possibly underlying its digestive effect, provides rationale for these therapeutic uses of D. bipinnata.