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Self-emulsifying drug delivery system (SEDDS) refers to a formulation comprising an isotropic mixture of natural and synthetic oils with hydrophilic or lipophilic surfactants and co solvents, which spontaneously emulsifies when exposed to gastrointestinal fluid to form oil-in-water emulsion [1-4]. The emulsion so produced is a clear dispersion in which the particle size of the dispersed phase ranges from nanometers to several microns. According to Đekić and Primorac, microemulsions are isotropic, transparent systems, which contain spherical droplets of water phase or oil phase, with diameter of average size from 10 to 100 nm, dispersed in a continuous oil or water phase, respectively whereas nanoemulsions are oil-in-water or water-in-oil emulsions with droplet size in the range of 50-1000 nm (preferably from 100 to 500 nm) [5]. The main difference between microemulsions and nanoemulsions is regarding their physical stability, appearance, and microstructure [5]. Pouton et al. reported that SEDDS can be dispensed in either soft gelatin or hard gelatin capsules. Upon oral administration, these systems form fine emulsions (or microemulsions) in the gastro-intestinal tract (GIT) with mild agitation provided by gastric mobility [6,7]. The difference between a SEDDS and self-micro emulsifying drug delivery system is that the former when diluted results in a droplet size between 100 and 300 nm and the later results in a droplet size of less than 50 nm [8]. SEDDS can overcome the problems associated with various drugs falling in various BCS classes, in case of BCS class III drugs, SEDDS can overcome the problem of enzymatic degradation, gut wall efflux and bioavailability [9]. On ingestion of SEDDS, it is initially acted upon by the gastric lipase in the stomach, which digests the lipid part of the formulation and further the gastric emptying enables the emulsification process before

Two simple and accurate ultraviolet (UV) spectrophotometric methods with better detection range for estimation of nimesulide in pure form and in solid dosage form were developed in the present studies using 50% v/v and 100% v/v acetonitrile as the solvent system. The linearity range of nimesulide in both the methods was found to be 10-50 micrograms/ml at a lambda max of 300 nm. The linear regression equations obtained by the least-square regression method are Abs = 1.33 x 10(-1).Conc + 1.89 x 10(-1) in 50% v/v acetonitrile and Abs = 1.05 x 10(-1).Conc + 1.14 x 10(-1) in 100% v/v acetonitrile. The detection limit as per the error propagation theory was found to be 0.46 microgram/ml and 1.04 micrograms/ml, respectively, in 50% v/v and 100% v/v acetonitrile. The developed methods were employed with high degree of precision and accuracy for the estimation of total drug content in three commercial tablet formulations of nimesulide. The results of the analysis were validated statistically and by recovery studies.

Objective:The self-micro-emulsifying drug delivery system (SMEDDS) of bambuterol hydrochloride was designed, prepared, and evaluated to overcome the problem of poor bioavailability. Methods:The designing of the formulation included the selection of oil phase, surfactant, and cosolvent/cosurfactant based on the saturated solubility studies. Psuedoternary phase diagram was constructed using aqueous titration method, to identify the self-emulsifying region. Different ratios of the selected surfactant and cosolvent/cosurfactant (Smix) were also studied and used to construct the ternary phase diagram. The prepared formulations of the SMEDDS were evaluated for drug content, morphology, globule size, robustness to dilution, emulsification time, optical clarity, and stability. Results:The formulation containing 10 mg bambuterol hydrochloride, triacetin (12.50% w/w), Tween 80 (43.75% w/w), and ethanol (43.75% w/w) was concluded to be optimized. The optimized SMEDDS not only showed optimum globule size, zeta potential, and drug content but was also found to be robust to dilution, formed emulsion spontaneously, and was stable. The optimized SMEDDS showed increased permeability of the drug across the intestinal membrane in ex vivo studies. Conclusion:The results suggest that bambuterol hydrochloride can be formulated as self-microemulsifying drug delivery system, and further, SMEDDS can be used to improve the oral bioavailability of bambuterol hydrochloride.

Introduction: Bambuterol is a long-acting b2-adrenoceptor agonist used in the treatment of asthma. It is a prodrug of terbutaline. Monograph of bambuterol hydrochloride describes non-aqueous titration for the estimation of bambuterol (B.P., 2001). Till date, simultaneous estimation of bambuterol hydrochloride and montelukast in distilled water, methanol, and chloroform by ultraviolet (UV) spectrophotometric method has been reported. Hence, the proposed method for the estimation of bambuterol hydrochloride in various buffers and solvent system was developed. Materials and Methods: Various solutions used during the study were freshly prepared. Distilled water, hydrochloric acid (Ramkem LR grade), potassium chloride (Qualigens AR grade), potassium dihyrogen phosphate (CDH LR), disodium hydrogen phosphate, sodium chloride (S.D. Fine Chem., extra pure), ethanol (Changshu Hongsheng Fine Chemical, AR), petroleum ether 60-80°C (Qualigen), and isopropyl alcohol (IPA) (Sisco Research Laboratories, extra pure) were used in the study. All the glasswares used were of borosilicate glass and were validated. Bambuterol hydrochloride was purchased from Yarrow Chem Products, Mumbai. UV-1800 Shimadzu spectrophotometer was used for the study. A simple, accurate, precise, and rapid UV spectrophotometric method was developed for the estimation of bambuterol hydrochloride in distilled water, pH 1.2 buffer, pH 6.8 buffer, pH 7.4 buffer, 90% v/v ethanol, IPA, and petroleum ether-ethanol (50%v/v) solution. Results: Bambuterol hydrochloride showed maximum absorbance at 264 nm in distilled water, pH 1.2 buffer, pH 6.8 buffer, pH 7.4 buffer, petroleum ether-ethanol (50%v/v) solution, and maximum absorbance at 265 nm in 90% ethanol and IPA. The proposed method is simple, rapid, and economical and R 2 value indicates good linearity. The method was validated statistically (P < 0.05). Further, the drug was found to be stable up to 24 h in various media studied. Conclusion: The method can be useful in the estimation of the content of bambuterol hydrochloride in the raw material and commercial tablet preparation. The method can be applied for the estimation of drug in dissolution studies at gastric and intestinal pH and estimation of drug content in oils and other water immiscible media.