Proniosomes for Penetration Enhancement in Transdermal System

Over the last few years an inclusive research has been done over provesicular approach for transdermal drug delivery. Skin has a very tough diffusion barrier inhibiting penetration of drug moiety which is rate limiting barrier for penetration of drugs. There are several approaches that deal with penetration enhancement across the skin. Vesicular and provesicular systems are promising amongst them. Vesicular systems including (niosomes, ethosomes, transfersomes and liposomes) are promising systems to cross this permeation barrier. But their major drawback is their unstability, which can be overcome by using provesicular approaches like proniosomes, protransfersomes and proliposomes. Provesicular approaches have been proposed to enhance the stability of vesicles. These approaches may overcome skin barrier properties and enhance percutaneous absorption. In these systems both type of drugs, hydrophilic and lipophillic drugs can be incorporated. The focus of this review is to bring together different aspects related to mechanism of skin permeation of provesicular system, proniosomes preparation and its applications as a carrier system. *Corresponding author, Mailing address: Dr. Geeta Aggarwal (Assistant Professor) Rayat and Bahra Institute of Pharmacy, Sahauran, District Mohali, Punjab -140104, India E.mail: [email protected] Article History:-----------------------Date of Submission: 05-02-2012 Date of Acceptance: 15-02-2012 Conflict of Interest: NIL Source of Support: NONE R e v i e w P a p e r C o v e r e d i n I n d e x C o p e r n i c u s w i t h I C V a l u e 4 .6 8 f o r 2 0 1 0 Int. J. Drug Dev. & Res., April-June 2012, 4 (2): 1-13 Covered in Scopus & Embase, Elsevier 1 upper skin layers are not expected to penetrate into viable skin[3]. Despite of several researches, the barrier function of the stratum corneum still remains a major problem, which makes the development of new transdermal drug delivery systems an interesting challenge[4]. Penetration enhancement is the most critical factor in the transdermal drug delivery. In order for transdermal drug delivery systems to be effective, the drug must obviously be able to penetrate the skin barrier and reach its target in required concentration. Significant effort has been devoted to developing strategies to overcome the impermeability of intact human skin. These strategies include passive and active penetration enhancement and technologies to bypass the stratum corneum. Vesicular systems have been widely studied as vehicles for dermal and transdermal drug delivery[5,6]. A number of vesicles systems such as liposomes, niosomes, ethosomes, emulsomes and transfersomes have been developed. The vesicular carrier such as niosomes has distinct advantage over conventional dosage forms because these particles can act as drug reservoir[7]. Niosomes are non ionic surfactant based multilamellar or unilamellar vesicles in which an aqueous solution of solute is entirely enclosed by a membrane resulted from organization of surfactants macro molecules as bilayers[8,9]. The non ionic surfactants for this use are usually single alkylchain surfactant or sorbitan esters. They are biodegradable, biocompatible and non immunogenic in nature. Niosomes have potential applications in the delivery of hydrophobic as well as hydrophilic drugs[10]. These vesicles are analogous to the liposomes (phospholipid vesicles) and serve as drug carrier because they can encapsulate both hydrophilic and lipophillic substrates[11]. Compared with the liposomes, niosomes offers higher osmotic stability with lower cost and greater availability of surfactants[12,13]. They improve the therapeutic performance of the drug molecules by delayed clearance from the circulation, protecting the drug from biological environment and restricting effects to target cells[14]. They have some disadvantages like physical and chemical instability, aggregation, fusion of vesicles and leaking or hydrolysis of the encapsulated drug. These factors may contribute in decreasing niosomal shelf life[15,16]. The disadvantages of vesicular system have been shown in Figure 1. To overcome these problems a noble provesicular approach proniosomes were developed. Proniosomes are non-ionic based surfactant vesicles, which may be hydrated immediately before use to yield aqueous niosome dispersions. Proniosomes are nowadays used to enhance drug delivery in addition to conventional niosomes[17]. Proniosomal system serves as a rate limiting barrier for absorption of drugs. These systems can overcome the permeation barrier of the skin and act as a penetration enhancers for the drugs[18]. The vesicles may serve as non toxic penetration enhancer for drug because of the ampiphillic nature of the vesicles; they are more stable and compatible with the skin[19]. Provesicular system can be simply converted into vesicular system, which presents a useful vesicular delivery concept with potential to deliver drugs via