en Virology Virology Original Research Original Research <p> <strong> Background </strong>:Wide distribution and low half-life of acyclovir has led to a high dose consumption of the drug. Recent studies have shown that encapsulation of acyclovir in nano-carriers can increase effectiveness and decrease its side effects. We investigated the inhibitory effect of acyclovir loaded nano-niosomes against herpes simplex virus type-1 (HSV-1) in cell culture. </p><p> <strong> Methods </strong>: In-vitro cytotoxicity study of empty niosomes (E-N), acyclovir loaded niosomes (ACV-N) and ACV as a free drug against HeLa cell line was performed by MTT assay and the viral titers was tested by TCID50 assay. </p><p> <strong> Results </strong>: The results indicated that a significant higher antiviral activity for acyclovir loaded nano-niosomes of about 3 times in comparison with free drug. </p><p> <strong> Conclusion </strong>: The results of this study revealed ACV-N have a higher antiviral activity compared with free drug it could be a suitable carrier for delivery of acyclovir in the treatment of HSV-1 infections. </p><p>  </p> Nano-niosomes, Herpes simplex virus, Cytotoxicity. 641 645 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-730&slc_lang=en&sid=1 Seyed Hamidreza Monavari hrmonavari@yahoo.com 200319475328460013296 200319475328460013296 Yes Department of Virology, School of Medicine, Iran University of Medical Sciences,Tehran, Iran. Mohammad Javad Mirzaeiparsa mparsa1389@gmail.com 200319475328460013297 200319475328460013297 No School of Advanced Medical Technologies, Tehran University of Medical Sciences,Tehran, Iran Bahram Bolouri tankbolouri@yahoo.com 200319475328460013298 200319475328460013298 No School of Advanced Medical Technologies, Iran University of Medical Sciences,Tehran, Iran. Soltan Ahmed Ebrahimi ebrahimi@iums.ac.ir 200319475328460013299 200319475328460013299 No Department of Pharmacology, School of Medicine, Iran University of Medical Scinces,Tehran, Iran. Angila Ataei-pirkooh gila@inbox.com 200319475328460013300 200319475328460013300 No Department of Virology, School of Medicine, Iran University of Medical Sciences,Tehran, Iran.