Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Egypt.
Eur J Pharm Biopharm. 2011 Jan;77(1):43-55. doi: 10.1016/j.ejpb.2010.10.011. Epub 2010 Nov 5.
Vinpocetine (Vin) existing oral formulations suffer poor bioavailability (∼7%) since Vin undergoes a marked first-pass effect (∼75%) and its absorption is dissolution rate-limited. In this study, a novel sustained release proniosomal system was designed using sugar esters (SEs) as non-ionic surfactants in which proniosomes were converted to niosomes upon skin water hydration following topical application under occlusive conditions. Different in vitro aspects (encapsulation efficiency, vesicle size and shape, effect of occlusion, in vitro release, skin permeation and stability) were studied leading to an optimized formula that was assessed clinically for transdermal pharmacokinetics and skin irritation. All formulae exhibited high entrapment efficiencies, regardless of the surfactant HLB. Vesicle size analysis showed that all vesicles were in the range from 0.63 μm to 2.52 μm which favored efficient transdermal delivery. The extent of drug permeation through the skin from the optimized formula--containing laurate SE with shorter fatty acid chain length and high HLB--was quite high (91%) after 48 h under occlusive conditions. The extent of absorption of Vin from proniosomes was larger when compared to the oral tablet with a relative bioavailability (F(rel)) of 206%. Histopathological evaluation revealed only moderate skin irritation when using SEs compared to skin inflammation when using Tween 80. Sugar esters proniosomes may be a promising carrier for vinpocetine, especially due to their simple scaling up and their ability to control drug release.
长春西汀(Vin)现有的口服制剂由于首过效应明显(约 75%)且吸收受溶解速率限制,其生物利用度较差(约 7%)。本研究采用糖酯(SE)作为非离子表面活性剂设计了一种新型的缓释前体囊泡系统,其中前体囊泡在封闭条件下经皮应用后皮肤水合时转化为囊泡。研究了不同的体外方面(包封效率、囊泡大小和形状、封闭效应、体外释放、皮肤渗透和稳定性),得出了一种优化的配方,并对其进行了经皮药代动力学和皮肤刺激性的临床评估。所有配方的包封效率都很高,与表面活性剂的 HLB 值无关。囊泡大小分析表明,所有囊泡的粒径均在 0.63 μm 至 2.52 μm 之间,有利于高效经皮给药。在封闭条件下 48 h 后,含有月桂酸 SE(短链脂肪酸和高 HLB)的优化配方中药物透过皮肤的渗透程度相当高(91%)。与口服片剂相比,前体囊泡中长春西汀的吸收程度更大,相对生物利用度(F(rel))为 206%。与使用 Tween 80 时的皮肤炎症相比,使用 SE 时皮肤的组织病理学评价仅显示出中度皮肤刺激。糖酯前体囊泡可能是长春西汀的一种有前途的载体,特别是由于其简单的放大和控制药物释放的能力。