Formulation of Natural Oil Nano-Emulsions for the Topical Delivery of Clofazimine, Artemisone and Decoquinate



The aim of this study was to formulate nano-emulsions comprising natural oils and the active pharmaceutical ingredients (APIs) clofazimine (CLF), artemisone (ATM) and decoquinate (DQ) in order to determine effectiveness of the nano-emulsions for topical delivery of the APIs. The APIs alone do not possess suitable physicochemical properties for topical drug delivery.


Nano-emulsions were formulated with olive and safflower oils encapsulating the APIs. Skin diffusion and tape stripping studies were performed. By using the lactate dehydrogenase (LDH) assay, in vitro toxicity studies were carried out on immortalized human keratinocytes (HaCaT) cell line to determine cytotoxicities due to the APIs and the nano-emulsions incorporating the APIs.


The nano-emulsions were effective in delivering the APIs within the stratum corneum-epidermis and the epidermis-dermis, were non-cytotoxic towards HaCaT cell lines (p < 0.05) and inhibited Mycobacterium tuberculosis in vitro.


Natural oil nano-emulsions successfully deliver CLF, ATM and DQ and in principle could be used as supplementary topical treatment of cutaneous tuberculosis (CTB).

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7H9/OADC :

Middlebrook 7HP Broth Base and Middlebrook AODC growth supplement


Analysis of variance


Active pharmaceutical ingredient



attB :

Phage attachment site


Colony-forming units




Cutaneous tuberculosis


Dulbecco’s modified eagle medium


Dimethyl sulfoxide

DQ :


ED :




EE% :

Entrapment efficiency


Fetal bovine serum


Glycerol-alanine-salts containing iron


Green fluorescent protein

HaCaT :

Immortalized human keratinocyte cells


High performance liquid chromatography

Hyg 50 :

Hygromycin B resistance gene




Lactate dehydrogenase


Limit of detection

Log D :

Octanol-water distribution coefficient


Limit of quantitation

M.tb :

Mycobacterium tuberculosis


Multidrug-resistant tuberculosis

MIC 90 :

90% Minimum inhibitory concentration


Non-essential amino acids

O :

Olive oil

O1 :

Olive oil nano-emulsion containing clofazimine

O2 :

Olive oil nano-emulsion containing artemisone

O3 :

Olive oil nano-emulsion containing decoquinate

O4 :

Olive oil nano-emulsion containing clofazimine, artemisone and decoquinate

O5 :

Olive oil nano-emulsion placebo

OD 600 :

Optical density reading taken at 600 nm


Phosphate buffer solution

Pen/Strep :



Polyvinylidene fluoride


Reactive oxygen species

S :

Safflower oil

S1 :

Safflower oil nano-emulsion containing clofazimine

S2 :

Safflower oil nano-emulsion containing artemisone

S3 :

Safflower oil nano-emulsion containing decoquinate

S4 :

Safflower oil nano-emulsion containing clofazimine, artemisone and decoquinate

S5 :

Safflower oil nano-emulsion placebo


Stratum corneum-epidermis

TB :



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Acknowledgments and Disclosures

This research project was supported by the South African Medical Research Council (MRC) Flagship Project Scheme with funds from the National Treasury under its Economic Competitiveness and Support Package, The authors thank the Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, South Africa and the National Research Foundation of South Africa for their financial contribution to this project [grant number CPRR13091742482]. Marelize Pretorius of the Statistical Consultation Services is thanked for the statistical analysis of the data and Ms. A. Brümmer for the cytotoxicity studies at the North-West University, Potchefstroom Campus, South Africa. Any opinion, findings and conclusions, or recommendations expressed in this material are those of the authors and therefore the NRF does not accept any liability in regard thereto. The authors declare no conflict of interest.

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Correspondence to Minja Gerber.

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Burger, C., Aucamp, M., du Preez, J. et al. Formulation of Natural Oil Nano-Emulsions for the Topical Delivery of Clofazimine, Artemisone and Decoquinate. Pharm Res 35, 186 (2018).

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Key Words

  • artemisone
  • clofazimine
  • cutaneous tuberculosis
  • decoquinate
  • nano-emulsions