Kashyap Nagariya

Nanoemulsions are only kinetically stable. However, the long term physical stability of nanoemulsions (with no apparent flocculation or coalescence) makes then unique and they are sometimes referred to as ‘Approaching thermodynamic stability. The inherently high colloid stability of nanoemulsions can be well understood from a consideration of their stearic stabilization (when using non-ionic surfactants and /or polymers) and how this is affected by the ratio of the adsorbed layer thickness to droplet radius. Successful ocular drug delivery has largely eluded solution due to, the physiological constraints imposed by the protective mechanisms of the eye that lead to poor absorption of drugs with very small fractions (less than 5%) of the instilled dose penetrating the cornea and reaching the intraocular tissues. Low drug contact time and poor ocular bioavailability due to drainage of solution, tear turnover and its dilution or lacrimation are the problems associated with conventional systems. Novel systems offer manifold advantages over conventional systems as they increase the efficiency of drug delivery by improving the release profile and also reduce drug toxicity. Conventional delivery systems get diluted with tear, washed away through the lacrimal gland and usually require administering at regular time intervals whereas novel emulsions are stable, have improved solubility, required reduced dosing frequency and release drug for prolonged periods of time. The aim of this review focuses on micro and nanoemulsions between 1 and 200 nm with a mean droplet size of about 40nm) for ocular drug delivery.

A simple, precise, accurate and stability-indicating reverse phase high performance liquid chromatography (RP-HPLC) method is developed for estimation of Levosalbutamol sulphate and Budesonide in bulk and suspension for inhalation dosage form. The method employed, with reverse phase Inertsil® 5μ C18 (250 × 4.0 mm) column in an isocratic mode, with mobile phase of acetonitrile: buffer in the ratio 40:60 (%v/v). The flow rate was 0.8 ml/min and effluent was monitored at 266 nm. Retention time was found to be 3.16 min., 17.94 min. and 20.90 min. The method was validated in terms of linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ) etc. in accordance with ICH guidelines. Linear regression analysis data for the calibration plot showed that there was good linear relationship between response and concentration in the range of 25 – 150% of the working concentration (r2 > 0.999) respectively. The LOD and LOQ values for were found to be 0.43, 0.72, 0.97 and 1.24 µg/ml respectively. No chromatographic interference from placebo and degradants were found. The proposed method was successfully used for estimation of Levosalbutamol sulphate and Budesonide in bulk and suspension for inhalation dosage forms.