Self-emulsification in chemical and pharmaceutical technologies

The interest in the low energy self-emulsification techniques has exploded in the recent years, driven by three main trends: by the transition to “greener” technologies in both its aspects—less energy consumption and replacement of the petrochemicals by natural ingredients; by the costly and maintenance demanding equipment for nanoemulsification; and by the quest for efficient and robust self-emulsifying formulations for oral drug delivery. Here, we first present a brief overview of the main known low-energy methods for nanoemulsion formation, focusing on their mechanistic understanding and discussing some recent advances in their development and applications. Next, we review three conceptually new approaches for self-emulsification in chemical technologies, discovered in the last several years. The colloidal features and the specific requirements of the self-emulsifying drug-delivery systems (SEDDS) are also discussed briefly. Finally, we summarize the current trends and the main challenges in this vivid research area.     

Paliperidone-Loaded Self-Emulsifying Drug Delivery Systems (SEDDS) for Improved Oral Delivery

The present research is aimed to improve the oral delivery of paliperidone by loading into self-emulsifying drug delivery systems (SEDDS). Oleic acid, Tween 80, and capmul MCM L8 were selected as oil, surfactant, and co-surfactant, respectively and phase diagram was constructed and the region was identified for the formation of SEDDS. The stable formulations were analyzed for globule size, robustness to dilution and in vitro drug release. The globule size of all the formulations was found to be in the range of 205 to 310 nm with good size uniformity and seems to be dependent on the proportion of oil in SEEDS formulation. The optimized formulation (F3) has been adsorbed onto neusilin and characterized. The DSC and XRD spectra unravel the presence of molecular state of paliperidone in solid SEDDS. The in vitro dissolution study indicates improved dissolution characteristics with higher dissolution efficiency for solid SEDDS (SEDDS-N) compared to pure drug. Further ex vivo permeation studies carried out using rat intestine suggest a 2- to 3-fold improvement in permeation for SEDDS compared to pure drug. In conclusion, SEDDS prove to be potential carriers for improved oral delivery of paliperidone.     

钙离子通道阻滞剂自乳化给药系统的形成机理

以一系列难溶性的二氢吡啶类钙离子通道阻滞剂作为模型药物,以自乳化面积和药物在自乳化给药系统(SEDDS)中的溶解度作为自乳化评价指标,建立各组分的分子描述参数与自乳化性质之间的定量函数关系,通过模型讨论分子结构对自乳化形成机理的影响.结果表明,自乳化的发生是各组分含量、分子间作用力、亲脂性和分子大小等多方面因素综合作用的结果.当混合表面活性剂分子较大且药物脂溶性较好时,SEDDS对难溶性药物的增溶能力较强;表面活性剂与助表面活性剂的质量比较大,混合表面活性剂的分子较大时,SEDDS的稀释稳定性较好.     

Advances in lipid carriers for drug delivery to the gastrointestinal tract

Lipid-based formulations have re-emerged as oral drug delivery systems. Advances in the techniques to evaluate the in vivo fate of the formulations, together with an improved knowledge of the gastrointestinal processes/barriers to the evolving lipid-based systems, could explain, at least partially, this revival. In addition, the use of lipid-based formulations is no longer limited to highly lipophilic drugs and has been extended to hydrophilic peptides and macromolecules. Last but not least, (targeted) nanocarriers have been developed exploiting gut physiology toward novel targets in the field. We herein review what we believe have been the major advances in oral drug delivery via lipid-based formulations in recent years, leading to their re-emergence as promising drug delivery systems for future clinical application.     

The Effect of Media Composition,pH, and Formulation Excipients on the In Vitro Lipolysis of Self-Emulsifying Drug Delivery Systems (SEDDS)

The objective of the present work was to investigate the effects of pH, ions, and excipients on the in vitro lipolysis of self-emulsifying drug delivery systems (SEDDS). Studies were performed in bio-relevant media using a pH stat autotitrator for analysis. The results demonstrated that alkaline media were essential for lipolysis, which was enhanced by divalent CaCl₂ ions and medium chain glycerides. Monovalent NaCl and the hydrophile-lipophile balance (HLB) of the surfactant had insignificant effect on lipolysis. Consequently, it was concluded that the activity of lipase, at an optimum pH of 6.5, is the predominant factors for digestion of SEDDS.