Formulation and evaluation of a topical niosomal gel containing a combination of benzoyl peroxide and tretinoin for antiacne activity
Authors: Sima Singh
Niranjan G Kotla
Thomas J Webster
Ankush Gupta
Journal: International Journal of Nanomedicine (2014)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: antiacne combination therapy; rabbit ear pinna model; retention efficiency; therapeutic index.
Affiliations: Department of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab, India.

Abstract:  A skin disease, like acne, is very common and normally happens to everyone at least once in their lifetime. The structure of the stratum corneum is often compared with a brick wall, with corneocytes surrounded by the mortar of the intercellular lipid lamellae. One of the best options for successful drug delivery to the affected area of skin is the use of elastic vesicles (niosomes) which can be transported through the skin through channel-like structures. In this study, a combination of tretinoin (keratolytic agent) and benzoyl peroxide (BPO) (a potent antibacterial) was given by using niosomes as promising carriers for the effective treatment of acne by acting on a pathogenic site. In this section, niosomal gel formulation encapsulated drugs have been evaluated for in vitro, ex vivo, and in vivo, for their predetermined characteristics; and finally the stability of the niosome gel was tested at different temperature conditions for understanding of the storage conditions required for maintaining the quality of formulation attributes. The prepared niosome was found to be in the range of 531 nm with a zeta potential of -43 mV; the entrapment efficiencies of tretinoin (TRA) and BPO niosomes were found to be 96.25%±0.56% and 98.75%±1.25%, respectively. The permeated amount of TRA and BPO from the niosomal gel after 24 hours was calculated as 6.25±0.14 μg/cm(2) and 5.04±0.014 μg/cm(2), respectively. A comparative drug retention study in Wistar rat skin using cream, an alcoholic solution, and a niosomal gel showed 11.54 μg, 2.68 μg, and 15.54 μg amounts of TRA and 68.85 μg, 59.98 μg, and 143.78 μg amounts of BPO were retained in the layers of skin, respectively. In vivo studies of the niosomal gel and antiacne cream of TRA and BPO showed that the niosomal gel was more efficacious than the antiacne cream because niosomal gels with a 4.16-fold lower dose of BPO provided the same therapeutic index at targeted sites in comparison to the antiacne cream. 

Retracted: Yes

PubPeer comments:
 Figure 16 shows the result of induced acne in rabbit ears, and how those respond to treatment with cream or niosomal gel. Each treatment group had three rats. In the Methods it is stated that *During the study, all animals were subjected to histological examination for assuring the effectiveness of the tested formulation.* However, almost all panels appear to show differently stretched, rotated, or shifted versions of other panels. In some cases, the similarities are within panels representing the same treatment group, but in other cases, the similarities are between panels of different groups. Boxes of the same color highlight areas that look similar. Could the authors clarify if these images are representing all three rabbits per group, and if not, why fewer rabbit samples were shown? ![file] , 
 We are looking into this. , 
 Retracted [18 June 2021] . --------------------------- The Publisher and Editor of International Journal of Nanomedicine wish to retract the published article. It came to the journals attention that several images shown in Figure 16 of the article appeared to be duplicated. Specifically, - The three panels in the top row, Control group (without inducing acne), appears to show duplicated versions of the same image which have been frame shifted and had their size altered. - The left and right panels of the row, Acne induced group 1, appear to show duplicated versions of the same image with the left panel being an enlarged version of the image on the right. - The middle panel of the row, Acne induced group 1, and the three panels of the row, Acne induced group 2, appear to be duplicated versions of the same image which have been frame shifted and undergone size alterations. - The left and middle panels of the row, Rabbit ear pinna after treatment with cream formulation for 14 days, appear to show duplicated regions of the same image which have been rotated. - The left panel of the row, Rabbit ear pinna after treatment with cream formulation for 14 days, appears to be duplicated with the image shown in the right panel of the bottom row, Rabbit ear pinna after treatment with niosomal gel formulation for 14 days, but this image has been rotated. - The left and middle panels of the bottom row, Rabbit ear pinna after treatment with niosomal gel formulation for 14 days, appear to show the same duplicated image with have been rotated and had their size altered. The authors could not provide a satisfactory explanation for the alleged image manipulation nor could they provide copies of the original images. Our decision-making was informed by our policy on publishing ethics and integrity and the COPE guidelines on retraction. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as u201cRetractedu201d. ,