ABSTRACT
Drug taste, which affects palatability, influences drug adherence. Sensory masking may be used to confound bitter tastes in drugs with other tastes and flavors; however, evaluation of sensory masking is difficult because of the existence of multiple tastes. In this study, a new two-bottle choice test was performed in rats to evaluate bitterness masking and determine the drug-to-sweetener ratio that significantly improves palatability. Sulfamethoxazole and trimethoprim were used as model bitter drugs, and sucralose was used as sweetener. The addition of sucralose and trimethoprim at a 0.13 : 1 ratio resulted in the greatest improvement in preference. This method is a useful new technique for evaluating the palatability of drug formulations.
Subject(s)
Excipients , Sweetening Agents , Rats , Animals , Drug Compounding , Taste , Trimethoprim, Sulfamethoxazole Drug CombinationABSTRACT
Cell-derived nanosized vesicles or exosomes are expected to become delivery carriers for functional RNAs, such as small interfering RNA (siRNA). A method to efficiently load functional RNAs into exosomes is required for the development of exosome-based delivery carriers of functional RNAs. However, there is no method to find exosome-tropic exogenous RNA sequences. In this study, we used a systematic evolution of ligands by exponential enrichment (SELEX) method to screen exosome-tropic RNAs that can be used to load functional RNAs into exosomes by conjugation. Pooled single stranded 80-base RNAs, each of which contains a randomized 40-base sequence, were transfected into B16-BL6 murine melanoma cells and exosomes were collected from the cells. RNAs extracted from the exosomes were subjected to next round of SELEX. Cloning and sequencing of RNAs in SELEX-screened RNA pools showed that 29 of 56 clones had a typical RNA sequence. The sequence found by SELEX was enriched in exosomes after transfection to B16-BL6 cells. The results show that the SELEX-based method can be used for screening of exosome-tropic RNAs.
Subject(s)
Drug Carriers/chemistry , Exosome Multienzyme Ribonuclease Complex/chemistry , Exosomes/chemistry , RNA, Small Interfering/administration & dosage , Sequence Analysis, RNA/methods , Animals , Cell Line, Tumor , Mice , SELEX Aptamer Technique/methods , TransfectionABSTRACT
The development of exosomes as delivery vehicles requires understanding how and where exogenously administered exosomes are distributed in vivo. In the present study, we designed a fusion protein consisting of Gaussia luciferase and a truncated lactadherin, gLuc-lactadherin, and constructed a plasmid expressing the fusion protein. B16-BL6 murine melanoma cells were transfected with the plasmid, and exosomes released from the cells were collected by ultracentrifugation. Strong luciferase activity was detected in the fraction containing exosomes, indicating their efficient labeling with gLuc-lactadherin. Then, the labeled B16-BL6 exosomes were intravenously injected into mice, and their tissue distribution was evaluated. Pharmacokinetic analysis of the exosome blood concentration-time profile revealed that B16-BL6 exosomes disappeared very quickly from the blood circulation with a half-life of approximately 2min. Little luciferase activity was detected in the serum at 4h after exosome injection, suggesting rapid clearance of B16-BL6 exosomes in vivo. Moreover, sequential in vivo imaging revealed that the B16-BL6 exosome-derived signals distributed first to the liver and then to the lungs. These results indicate that gLuc-lactadherin labeling is useful for tracing exosomes in vivo and that B16-BL6 exosomes are rapidly cleared from the blood circulation after systemic administration.
