International Journal of Pharmaceutics 326 (2006) 174–181 Pharmaceutical Nanotechnology Hypericin-loaded nanoparticles for the photodynamic treatment of ovarian cancer Magali Zeisser-Labou` ebe, Norbert Lange, Robert Gurny, Florence Delie ∗ Department of Pharmaceutics and Biopharmaceutics, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30 Quai E. Ansermet, CH-1211 Geneva 4, Switzerland Received 17 May 2006; received in revised form 6 July 2006; accepted 7 July 2006 Available online 15 July 2006 Abstract A photodynamic approach has been suggested to improve diagnosis and therapy of ovarian cancer. As Hypericin (Hy), a natural photosensitizer (PS) extracted from Hypericum perforatum, has been shown to be efficient in vitro and in vivo for the detection or treatment of other cancers, Hy could also be a potent tool for the treatment and detection of ovarian cancer. Due to its hydrophobicity, systemic administration of Hy is problematic. Thus, polymeric nanoparticles (NPs) of polylactic acid (PLA) or polylactic-co-glycolic acid (PLGA) were used as a drug delivery system. Hy-loaded NPs were produced with the following characteristics: (i) size in the 200–300nm range, (ii) negative zeta potential, (iii) low residual PVAL and (iv) drug loading from 0.03 to 0.15% (w/w). Their in vitro photoactivity was investigated on the NuTu-19 ovarian cancer cell model derived from Fischer 344 rats and compared to free drug. Hy-loaded PLA NPs exhibited a higher photoactivity than free drug. Increasing light dose or incubation time with cells induced an enhanced activity of Hy-loaded PLA NPs. Increased NP drug loading had a negative effect on their photoactivity on NuTu-19 cells: at the same Hy concentration, the higher was the drug loading, the lower was the phototoxic effect. The influence of NP drug loading on the Hy release from NPs was also investigated. © 2006 Elsevier B.V. All rights reserved. Keywords: Photodynamic therapy; Biodegradable nanoparticles; Hypericin; Ovarian cancer; In vitro; Drug delivery system 1. Introduction Ovarian carcinoma is the fourth most frequent cause of cancer-related death in women in the United States (Jemal et al., 2005). Approximately 22,000 new cases of ovarian cancer are diagnosed each year and 16,000 per year die from this disease. Ovarian cancer is often called the “silent killer” because symp- toms observed in the early stages are not easily connected to the disease (Goff et al., 2000). Thus, almost 70% of diagnosed women already show extended growth of malignant cells cor- responding to stages III and IV of the disease (Heintz et al., 2001). The currently recommended treatment is a combination of surgery followed by chemotherapy. However, ovarian cancer is characterized by the development of peritoneal micrometas- tases, which are not always removed by this standard treatment, mainly because micrometastases remain undetected by the con- ∗ Corresponding author. Tel.: +41 22 379 6573; fax: +41 22 379 6567. E-mail address: Florence.Delie@pharm.unige.ch (F. Delie). ventional detection methods. As a consequence, up to 50% of treated patients have a relapse and will inevitably die from their disease. The relative 5-year survival rate varies considerably with the disease stage at the moment of diagnosis. For patients diagnosed with stage I, the 5-year survival rate is 94%, compared to 19% for those diagnosed with stage IV (Gloeckler Ries et al., 2003). A photodynamic approach has been suggested to improve diagnostic and therapeutic methods, offering the opportunity of early detection and more effective eradication of peritoneal micrometastases (Allison et al., 2005). Photodetection (PD) and photodynamic therapy (PDT) are based on the administration of drugs known as photosensitizers (PS) that are preferentially taken up and/or retained by malignant tissues (Sharman et al., 1999; Lange, 2003; Castano et al., 2004). The PS alone is harmless and ideally has no effect on either healthy or abnormal tissues. Illumination with light at the appro- priate wavelength and dose induces either fluorescence allowing the detection of diseased tissues or photochemical reactions that result in tissue destruction. For several years, PD and PDT have been widely investigated in the field of cancer or other diseases 0378-5173/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.ijpharm.2006.07.012