Title : Effect of chemical properties on liposomal encapsulation of radiopharmaceutical tracers
Abstract:
Drug loading in liposomes can be performed either passively (during liposome formation) or actively (after liposome formation). Thus, the trapping efficiency of hydrophilic drugs in passive liposome encapsulation is relatively low (around 30%) due to the limited volume of the encapsulated aqueous component in the liposome core. By using active loading methods, such as pH gradient entrapment, the trapping efficiency of hydrophilic drugs can be increased to 100%. This study aimed to reach the maximum encapsulation efficiency to upload drugs and radioisotopes by using different types of chemical agent and a different loading technique (the pH gradient technique). The 99mTc-radiopharmacueutical kit has a pH range of 8.3–9.1, if prepared without the admission of air, and a shelf life of 8 hours. However, the addition of 2 ml of air changes the final pH range to7.5–9.0. In this study, the liposomes had an extra-liposomal pH of 7.2 and an interior pH of 5.0 in order to ensure better drug encapsulation. Many trials were performed, and the formula with the smallest particle size possible was selected. Trisodium citrate and ammonium sulfate were tested individually as hydration buffers with different concentrations. The ph gradient technique and drug encapsulation during liposome formation both offer advantages over using drugs without liposomes. Furthermore, the ammonium sulfate manifested the smallest particle size when compared to the other buffers. By adding cationic particles, the targeting efficiency was enhanced and the biodistribution of the radiopharmaceutical increased. The target-non-target ratio produce interesting results, as the uptake and specificity were enhanced.
Audience take-away:
- Audience will be able recognize the advantages of using nanoprticles encapsulation for drug delivery.
- They will know the chemicals and techniques that affect the nanopraticle sizes and charge in order to enhance the drug loading as well as the biodistribution of the drug.
