Gelation of pectin caused by divalent cations especially calcium ions has been applied to develop an ophthalmic formulation of azithromycin in the present study. Rapid elimination of drug on instillation into cul de sac would be minimal with in situ gelling ophthalmic solution leading to increased precorneal contact time and prolonged drug delivery. In the formulation development studies pectin was used in different concentrations (1-5% w/v) and different proportions of the hydrocolloids hydroxypropyl methylcellulose and sodium carboxymethyl cellulose of different grades of viscosity were used. The primary criteria for formulation optimization were gelling capacity and rheological behaviour. In addition, formulations were evaluated for pH, and antimicrobial efficacy and drug release. The clarity, pH, gelation in simulated tear fluid and rheological properties of the optimized formulations were satisfactory. The formulations inhibited the growth of Staphylococcus aureus effectively in cup–plate method and were proved to be safe and non irritant on rabbit eyes. The results indicate that pectin based in situ gels can be successfully used to prolong the duration of action of azithromycin.

Etoricoxib is a potent, orally active, and highly selective COX-2 inhibitor that exhibits anti-inflammatory, analgesic, and antipyretic activities. The present research was undertaken to develop mouth dissolving films of etoricoxib to have rapid onset of action. Mouth dissolving film (MDF) is a better alternate to oral disintegrating tablets due to its novelty, ease of use, and the consequent patient compliance. Solubility enhancement and taste masking of etoricoxib were the two challenges solved by formulating druginclusion complex with beta-cyclodextrin (BCD). MDF prepared by solvent casting etoricoxib-BCD complex along with HPMC as film forming polymer was found to possess desirable physicomechanical properties. In vitro release of etoricoxib from MDF in simulated salivary fluid and 0.1 N HCl was more than 95% within 2 minutes. Taste masking and in vivo disintegration were in acceptable range as assessed by human volunteers. Etoricoxib MDF was further characterized by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy. The index of analgesia shown by etoricoxib MDF was comparable to that of immediate release tablets (100% activity within 40 minutes) in animal studies. Conclusively, the present study documents the development of a commercially viable formula for an MDF of etoricoxib with rapidity in pain management.

Chromium pillared montmorillonite and vermiculite catalysts have been prepared by intercalation with hydrolyzed metal ion solution. Pillaring solutions with different chromium concentrations were prepared by varying the base to chromium ratio. The catalysts were characterized by nitrogen adsorption, XRD, and IR studies. The nature of the acid sites was characterized by means of IR spectra data on pyridine adsorbed chromium pillared catalysts. The acidity of the samples was determined by butylamine titration. DSC has been used in the present study to probe the nature of the surface acidity, its heterogeneity, acid strength, and density of acidic sites. Cumene cracking was carried out as a test reaction of Brønsted acidity. Both the density and strength of Brønsted acid sites were found to influence the cracking activity.

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