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Development and characterization of amphotericin B bearing emulsomes for passive and active macrophage targeting
1Drug Delivery Research Laboratory, Department of Pharmaceutical Sciences, Dr Hari Singh Gour Vishwavidyalaya, Sagar, MP, India. swatig25@gmail.com
Abstract:
The antifungal and antileishmanial agent amphotericin B (AmB) has been complexed with lipids to develop a less toxic formulation of AmB. Because lipid particles are phagocytized by the reticuloendothelial system, lipid associated AmB should be concentrated in infected macrophages of liver and spleen and be very effective against visceral leishmaniasis (VL) and systemic fungal infections. Therefore, AmB was formulated in trilaurin based nanosize lipid particles (emulsomes) stabilized by soya phosphatidylcholine (PC) as a new intravenous drug delivery system for macrophage targeting. Emulsomes were prepared by cast film technique followed by sonication to obtain particles of nanometric size range. Formulations were optimized for AmB to lipid ratio, sonication time and PC to trilaurin ratio. Emulsomes were modified by coating them with macrophage-specific ligand (O-palmitoyl mannan, OPM). The surface modified emulsomes and their plain counterparts were characterised for size, shape, lamellarity and entrapment efficiency. Fluorescence microscopy study showed significant localization of plain and coated emulsomes inside the liver and spleen cells of golden hamsters. In vivo organ distribution studies in albino rats demonstrated that extent of accumulation of emulsome entrapped AmB in macrophage rich organs, particularly liver, spleen and lungs was significantly high when compared against the free drug (AmB-deoxycholate or AmB-Doc). The rate and extent of accumulation were found to increase further on ligand anchoring. Further, a significantly higher (P < 0.05) drug concentration in the liver was estimated over a period of 24 h for OPM coated emulsomes than for plain emulsomes. We concluded that OPM coated emulsomes could fuse with the macrophages of liver and spleen due to ligand-receptor interaction and could target the bioactives inside them. The proposed plain and OPM coated emulsome based systems showed excellent potential for passive and active intramacrophage targeting, respectively and the approach could be a successful alternative to the currently available drug regimens of VL and systemic fungal infections.
Insights
New amphotericin B (AmB) emulsomes target macrophages for treating fungal infections and visceral leishmaniasis. Ligand-coated particles show enhanced drug concentration in liver and spleen, offering a promising alternative treatment.
Area of Science:
- Pharmacology
- Nanotechnology
- Drug Delivery Systems
Background:
- Amphotericin B (AmB) is an effective antifungal and antileishmanial agent but exhibits toxicity.
- Lipid formulations of AmB aim to reduce toxicity and improve targeting to infected macrophages.
- Visceral leishmaniasis (VL) and systemic fungal infections predominantly affect macrophages in the liver and spleen.
Purpose of the Study:
- To develop novel trilaurin-based nanosize lipid particles (emulsomes) for intravenous delivery of AmB.
- To enhance macrophage targeting of AmB using surface modification with a macrophage-specific ligand (O-palmitoyl mannan, OPM).
- To evaluate the in vivo efficacy and organ distribution of plain and OPM-coated AmB-loaded emulsomes.
Main Methods:
- Emulsomes were prepared using the cast film technique and sonication, optimizing AmB to lipid ratio, sonication time, and phosphatidylcholine (PC) to trilaurin ratio.
- Emulsomes were surface-modified with OPM for active targeting.
- Characterization included size, shape, lamellarity, and entrapment efficiency.
- In vivo studies in golden hamsters and albino rats assessed emulsome localization, organ distribution, and drug concentration.
Main Results:
- Plain and OPM-coated emulsomes demonstrated significant localization within liver and spleen cells.
- AmB-loaded emulsomes showed higher accumulation in macrophage-rich organs (liver, spleen, lungs) compared to free AmB.
- OPM-coated emulsomes exhibited increased drug accumulation in the liver over 24 hours compared to plain emulsomes.
- Ligand anchoring (OPM coating) further enhanced the rate and extent of AmB accumulation.
Conclusions:
- OPM-coated emulsomes facilitate targeted delivery of AmB to macrophages in the liver and spleen via ligand-receptor interactions.
- Both plain and OPM-coated emulsomes show potential for passive and active intramacrophage targeting, respectively.
- This emulsome-based approach offers a potentially successful alternative to current treatment regimens for VL and systemic fungal infections.
