Cisplatin is one of the most widely used agents in the treatment of solid tumors, but its clinical utility is limited by toxicity. The development of less toxic, liposomal formulations of cisplatin has been hampered by the low water solubility and low lipophilicity of cisplatin, resulting in very low encapsulation efficiencies. We describe a novel method allowing the efficient encapsulation of cisplatin in a lipid formulation; it is based on repeated freezing and thawing of a concentrated solution of cisplatin in the presence of negatively charged phospholipids. The method is unique in that it generates nanocapsules, which are small aggregates of cisplatin covered by a single lipid bilayer. The nanocapsules have an unprecedented drug-to-lipid ratio and an in vitro cytotoxicity up to 1000-fold higher than the free drug. Analysis of the mechanism of nanocapsule formation suggests that the method may be generalized to other drugs showing low water solubility and lipophilicity.The clinical use of cis-diamminedichloroplatinum(II) (cisplatin) and many of its analogs faces three major problems: 1) serious dose-limiting toxicities in particular nephrotoxicity and neurotoxicity; 2) rapid inactivation of the drug as a result of complexation to plasma and tissue proteins; and 3) the frequent occurrence of platinum resistance [1][2][3][4][5] . In general, these problems can be reduced by shielding of a drug from the extracellular environment by means of a lipid coating. However, in many cases this approach fails because of inefficient encapsulation of the drug in lipid formulations resulting in low drug uptake by the tumor 6 . This is particularly true for cisplatin: the low water solubility and low lipophilicity of cisplatin result in lipid formulations with a very low drug-to-lipid ratio 7-9 . One approach is to synthesize lipophilic derivatives of cisplatin that can be efficiently encapsulated in large multilamellar liposomes 10 . Here, we describe a new method to efficiently encapsulate native, non-derivitized cisplatin in a lipid formulation. Nanocapsules of cisplatinOur method involves hydration of a dry lipid film composed of equimolar amounts of dioleoyl-phosphatidylserine (PS) and dioleoyl-phosphatidylcholine (PC), with a buffered solution (pH 7.4) of 5 mM cisplatin followed by 10 freeze-thaw (FT) cycles, and removal of free (extravesicular) cisplatin by centrifugation. The cisplatincontaining lipid suspension (cisPt-PS/PC) was extremely cytotoxic (Fig. 1a) with a typical IC 50 (the drug concentration at which cell growth is inhibited by 50%) of approximately 2 nM as compared with 0.5 µM for the free drug (conventional cisplatin). A lipid suspension not loaded with cisplatin (blank) was not cytotoxic, and mixing conventional cisplatin with the blank lipid suspension did not increase the cytotoxicity of cisplatin.Omitting the freeze-thaw step, or leaving out the negatively charged PS in the lipid mixture, resulted in a dramatic decrease in cytotoxicity (Fig. 1b). This decrease in cytotoxicity was paralleled by a sim...

Liposomes are vesicles consisting of spherical phospholipid bi-layers with specific properties making them useful for topical application of drugs. Liposome research has expanded considerably over the last 30 years and nowadays, it is possible to construct a wide range of liposomes varying in size, phospholipids composition and surface characteristics to suit the specific application for which they are intended. In dermatology, the topical application of liposomes has proven to be of therapeutic value. Liposomes can be used as carriers for hydrophilic as well as lipophilic therapeutic agents because of their amphipathic character. They may improve stabilization of instable drugs by encapsulating them and serve as penetration enhancers facilitating the transport of compounds that otherwise cannot penetrate the skin. Liposomes help in reducing skin irritation by sustaining the release of drugs and by hydration of the epidermis. They also have the potential to target drugs into the pilosebaceous structures and hence they have an additional advantage for treatment of hair follicle-associated disorders. Clinical data indicate that 5-ALA encapsulated in liposomes improves the quality of Fluorescence Diagnosis by ALA-induced Porphyrins (FD) and optimizes the results of Photodynamic Therapy (PDT).

MMS might be superior to standard excision for cSCCs of the head and neck because of a lower rate of recurrence.

Human leukocyte antigen (HLA) class II associations with two subtypes of vitiligo: vitiligo vulgaris and halo nevi associated with vitiligo were investigated. In previous studies associations between vitiligo and HLA antigens have been reported but these two subtypes have never been taken into account. However from a clinical and histological point of view, a difference in (auto)-immune pathogenesis can be expected. This difference might be reflected in an association with different HLA alleles. Seventy-six unrelated Dutch Caucasians, 40 with vitiligo vulgaris and 36 with halo nevi associated with vitiligo were included. A panel of randomly chosen HLA typed healthy Dutch blood donors (n = 2400) served as control population. HLA-DR and -DQ typing was carried out on blood samples by amplifying genomic DNA using polymerase chain reaction followed by dot blot hybridization with sequence specific oligonucleotides. The main outcome measures were odds ratio (OR), uncorrected P-value (P(u)) and corrected P-value. There were distinct differences in the clinical manifestations between vitiligo vulgaris and halo nevi associated with vitiligo with respect to precipitating factors, extent and progress of the disease and the association with other auto-immune diseases in the two subtypes and their respective first degree family members. Our stratification reveals differences in HLA class II between both subtypes and between subtypes and controls. A case-control association study showed a significant positive association of HLA-DR4 (OR = 2.787, P(u) = 0.0022) and DR53 (OR = 2.249, P(u) = 0.0153) and a negative association of HLA-DR3 (OR = 0.195, P(u) = 0.0024) with vitiligo vulgaris. The group with halo nevi associated with vitiligo did not show these associations, but had a significant negative association with HLA-DR11 (OR = 0.083, P(u) = 0.0067). In conclusion, the differences in HLA association within clinical subtypes of vitiligo support our suggestion that vitiligo vulgaris and halo nevi associated with vitiligo have distinct pathogenic mechanisms.