Part III of the series – Encapsulating cannabinoids in lipid-based nanoparticles: THC vs. CBC

增强大麻素的治疗疗效

在我们以前的技术说明中，我们报道了CBD vs THC（1）的包封成脂质的纳米颗粒。在这里的工作继续在研究将不同的大麻素的差异封装到与主要大麻素，THC之一特别开发的相同的脂质的药物递送系统中的差异。我们的一系列实验中的总体假设是大麻素的相似性可以在纳米颗粒稳定性和封装效率方面具有类似的结果。但正如我们在本系列开发的各种比较中所说，结构的小变化可能具有有趣的结果。让我们在四氢呋喃醇（THC）和大麻溴（CBC）上仔细观察这里。

大麻类医学历史悠久their therapeutic effects (2). However, due to their lipophilic nature, they are poorly absorbed by the digestive system which hinders their potential as therapeutics (3).

Nanoparticles offer a solution to this problem. By encapsulating these hydrophobic molecules into water miscible vehicles, they can be better absorbed by the digestive system, thus enhancing their therapeutic effect (4).

At Ascension Sciences, we have explored different types of nanoparticles to encapsulate cannabinoids. Specifically, we developed multiple lipid-based formulations that have been successfully optimized for the encapsulation of THC. One of the next steps in our exploration was to use these optimized parameters to encapsulate CBC, a non-psychotropic cannabinoid, into three types of lipid-based nanoparticles: emulsions, liposomes and solid-lipid nanoparticles (SLNPs) – Figure 1.

Figure 1: Lipid-based nanoparticles

THC vs. CBC

这一技术注意起了比较感情n the encapsulation of THC vs. CBC using formulation parameters that were previously optimized for THC. The goal of the study was to provide insights into how the formulation optimized for one cannabinoid translates into another, and where one lead formulation concept can become the starting point for an alternate active ingredient.

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OVERVIEW

Tetrahydrocannabinol (THC) and cannabichromene (CBC), along with cannabinol and cannabidiol, are the most abundant naturally occurring cannabinoids (5, 6). As seen in Fig. 2, these two cannabinoids have similar molecular structure. However, small structural differences result in THC and CBC having different chemical properties and effects on our body’s endocannabinoid system.

As mentioned in the previous article, THC is the primary psychoactive compound found in the cannabis plant and works as a partial agonist of cannabinoid receptors (CB1 and CB2) and has effects on emotion, pain, digestion, and appetite (7, 8). CBC, a non-psychoactive component in marijuana (9) has been discovered to not interact with CB1 receptors but to interact with transient receptor potential (TRP) cation channels, which inhibit endocannabinoids inactivation and are linked to pain and inflammation (10, 11, 12, 13). CBC, like other natural plant products, can inhibit the cellular reuptake of endocannabinoids (14). While CBC is one of the prominent non-psychoactive cannabinoids having a range of benefits, there remains a lack of basic insights about its pharmacology. Some potential uses of CBC include: antibacterial effects (15), anti-inflammatory action and pain relief (16), anti-depressant effects (17), anti-cancer (18), anti-acne activities (19), and promotion of cell growth (20).

Figure 2: Molecular structure of THC and CBC

在该具体研究中，我们将每个大麻素配方的包封效率和纳米颗粒稳定进行了比较。Encapsulation efficiency is the amount of cannabinoid that is encapsulated into the nanoparticle upon formulation. Nanoparticle stability is determined by measuring the particle size and polydispersity index (PDI) every 7 days for a month of storage at different conditions to monitor any significant changes in the properties of the particles. A stable nanoparticle does not significantly change in size and PDI remains below 0.2, meaning that the particle population is uniform in size and there is no aggregation of the particles over time. Lastly, we determined the cannabinoid retention, which is the amount of cannabinoid that remained encapsulated inside the nanoparticles after 35 days of storage.

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方法

The formulation parameters for each nanoparticle type can be found in Table 1. Each formulation type was used on either THC or CBC using the same formulation parameters.

所有纳米颗粒制剂都是使用来自精密纳米系统的纳米可血清BbChtop微流体仪器实现的低能量方法制备。

	Emulsion	Liposome	SLNP
Lipid composition	TweenⓇ80: SpanⓇ80 : Hemp Seed Oil	POPC : Chol : DSPE-PEG2000	Chol : POPC : DSPE-PEG2000
Organic solvent	乙醇
Aqueous solvent	Deionized water	PBS pH 7.4
Solvent removal	Dialysis in aqueous media
Lipid:Cannabinoid	10:1

Table 1: Formulation parameters for the different types of nanoparticles

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RESULTS

Encapsulation efficiency (EE%)

* SLNP: Solid-Lipid Nanoparticle

Figure 3: Encapsulation efficiency of THC and CBC in each type of nanoparticle

Type of nanoparticle	THC concentration, mg/mL	CBC浓度，mg / ml
Liposome	0.97	0.56
Emulsion	3.89	3.47
SLNP	0.30	0.31

Table 2: Encapsulated cannabinoid concentration

* THC solubility in water: 2.8 ug/mL (21)

*CBC solubility in water: 1.54 ug/mL (22)

• THC and CBC both showed similar EE% in the nanoemulsion.
• Comparing the two cannabinoids, liposomes showed a difference in EE% between the two. THC liposomes showed greater EE% of 72% compared to 45% for CBC liposomes.
• SLNPs showed similar EE% between the two cannabinoids and the highest EE% between the different nanoparticle types for both THC and CBC.

Nanoparticle stability over 35 days of storage at 4°C

SLNP：固体脂质纳米粒子

图4：纳米颗粒在4℃下储存超过35天的稳定性。

• THC and CBC liposomes showed the smallest particle size among all nanoparticles of ~ 50 nm and remained stable after 35 days at 4°C.
• 在35天的时间内，THC与乳液中的CBC（〜1000）相比，在4℃下与CBC（〜1000）相比，在4℃下显示得更小。
• 所有PDI值低于0.3，表明颗粒在储存35天没有聚集。
• SLNP particles are not as stable as the other two nanoparticles, as variable sizes are seen through the 35 days period.

Cannabinoid retention over 35 days of storage at room temperature – dark, light and 4°C conditions.

Figure 5: Cannabinoid retention in the nanoparticle over 35 days of storage at room temperature, dark and light conditions and 4°C

• CBC in both the liposome and emulsion showed higher drug retention at room temperature dark compared to the light condition. The same trend is true for SLNPs, but the difference is not as prominent (data are not shown).
• THC in emulsion showed lower drug retention compared to CBC at 4°C, 10% vs 65% respectively, and similar drug retention between the two cannabinoids in the light and dark conditions.
• In liposomes, both cannabinoids showed similar drug retention when stored at 4°C and r.t. dark. However, when stored at r.t. light condition a lower drug retention for CBC was observed (72% for THC compared to 42% for CBC).
• At the room temperature dark condition, THC and CBC showed similar drug retention in all nanoparticles (around 60%).

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CONCLUSION

THC和CBC演示不同的行为different nanoparticles and conditions. THC and CBC have similar EE% in emulsions and SLNPs. However, EE% between these two cannabinoids are different when formulated into liposomes (lower for CBC). Similar particle size is seen for these two cannabinoids in liposomes at 4°C, while particle size is significantly different in emulsions and SLNPs (larger particle size for CBC in these two nanoparticles). Furthermore, drug retention results show that different types of nanoparticles retain THC and CBC differently in variable conditions. As mentioned before in our previous articles, small differences in the molecular structure of cannabinoids might result in differences in their physicochemical properties and their characterization in nanoparticles. Indeed, more studies are needed to understand the molecules interaction in the interface that causes these changes. CBC has a longer flexible aliphatic side chain compared to THC (Fig. 2), which in the case of liposomes could affect its interaction with lipid tails and placement within the bilayer. EE% values seem to indicate these interactions to be unfavourable for the chosen lipid composition.

Based on these findings, we can conclude that the formulation developed for THC is not optimal for CBC and can be further improved to obtain nanoparticles with desired properties.

FUTURE STUDIES

ASI aims to develop and optimize a formulation that shows a higher EE% (<90%), API stability and bioavailability for CBC based on the formulations explored in this experiment.

在这里了解有关Ascension Sciences的更多信息！

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