Biodistribution of long-circulating PEG-liposomes in a murine model of established subcutaneous abscesses

Relation between Skin Pharmacokinetics and Efficacy in AmBisome Treatment of Murine Cutaneous Leishmaniasis

AmBisome (LAmB), a liposomal formulation of amphotericin B (AmB), is a second-line treatment for the parasitic skin disease cutaneous leishmaniasis (CL). Little is known about its tissue distribution and pharmacodynamics to inform clinical use in CL. Here, we compared the skin pharmacokinetics of LAmB with those of the deoxycholate form of AmB (DAmB; trade name Fungizone) in murine models of Leishmania major CL. Drug levels at the target site (the localized lesion) 48 h after single intravenous (i.v.) dosing of the individual AmB formulations (1 mg/kg of body weight) were similar but were 3-fold higher for LAmB than for DAmB on day 10 after multiple administrations (1 mg/kg on days 0, 2, 4, 6, and 8). After single and multiple dosing, intralesional concentrations were 5- and 20-fold, respectively, higher than those in the healthy control skin of the same infected mice. We then evaluated how drug levels in the lesion after LAmB treatment relate to therapeutic outcomes. After five administrations of the drug at 0, 6.25, or 12.5 mg/kg (i.v.), there was a clear correlation between dose level, intralesional AmB concentration, and relative reduction in parasite load and lesion size (R² values of >0.9). This study confirms the improved efficacy of the liposomal over the deoxycholate AmB formulation in experimental CL, which is related to higher intralesional drug accumulation.

Effectiveness of topical gel of medical leech (Hirudo medicinalis) saliva extract on patients with knee osteoarthritis: A randomized clinical trial

Leech saliva extract (LSE) in the liposome-based gel was used as a supplementary treatment to relief the signs and symptoms of osteoarthritis (OA). The saliva of medical leech was extracted and nano liposomes were used to formulate the supplement to enhance skin absorption. A clinical trial was designed to evaluate the therapeutic effects of LSE liposomal gel. Lenquesne and VAS questionnaires were used as indexes of this supplement therapy efficacy for 30 days. Questionnaires analysis showed that after one-month administration of LSE liposomal gel, patients' pain was relieved approximately up to 50%; also, due to reduction in joint inflammation and stiffness, the range of motion was increased and the patients' quality of life was enhanced (p < 0.001). LSE nano scaled liposomal gel as an innovative supplement therapy in OA patients, makes desirable therapeutic approach, which seems to make a significant impact on patient's quality of life and self-care capability.

Tumour Angiogenesis, Vascular Biology and Enhanced Drug Delivery

It is now common knowledge that for a solid tumour to become life-threatening clinically, an adequate blood supply to the neoplasm has to be established. Although neovascularisation via angiogenesis leads to a subsequent rapid growth of the tumour mass, it provides the most reliable route by which neoplastic cells may be reached by cytotoxics. In addition, for a majority of tumours, the lesion's vasculature is more permeable and tortuous than that of the surrounding healthy host tissue. Such deviation potentiates selective delivery of drugs to be achieved. This review examines, from various viewpoints, the area of tumour angiogenesis and vascularisation, currently one of the most fertile and active fields of cancer research.

Persistent contrast enhancement by sterically stabilized paramagnetic liposomes in murine melanoma

In the present research, we investigated the use of paramagnetic liposomes as contrast agents (CAs) for the detection of solid tumors. The liposomes were sterically stabilized by a polyethylene glycol (PEG) coating, and their size was constrained to approximately 100 nm. Dimyristoyl-sn-glycero-3-phosphoethanolamine-N-diethylene-triaminepentaacetate (DMPE-DTPA) was used as the gadolinium-carrying fatty acid chain. The relaxation properties were characterized through nuclear magnetic relaxation dispersion (NMRD) measurements, and analyzed with the use of theories and computer programs that are adequate for slowly rotating systems. Their relaxivity at 1.5 T was found to be acceptable for in vivo use. We then tested the liposomes against B16-F10 murine melanomas using standard T1-weighted schemes at 1.5 T, and concentrations corresponding to 0.03 mmol/kg of gadolinium (i.e., three to six times lower than the concentration of the small gadolinium complexes in clinical use). The blood half-life was found to be 120 +/- 20 min. The experiments show a good contrast enhancement in the tumor (33% +/- 22%) 2 hr after administration, a further increase (43 +/- 27%) 20 hr after administration, and a decrease (25% +/- 14%) 54 hr after administration. High persistence of the CA was also observed in the liver and intestine, as expected in a hepatobiliar excretion pathway.