Application of a liquisolid technique to cannabis sativa extract compacts: Effect of liquid vehicles on the dissolution enhancement and stability of cannabinoids

Preparation and Evaluation of Directly Compressible Orally Disintegrating Tablets of Cannabidiol Formulated Using Liquisolid Technique

This study demonstrated the implementation of a liquisolid technique to formulate directly compressible orally disintegrating tablets (ODTs). Cannabidiol (CBD), a hydrophobic cannabinoid, was prepared as a liquisolid powder using microcrystalline cellulose-colloidal silicon dioxide as a carrier-coating material. Different liquid vehicles differing in their volatility, hydrophilicity, and viscosity were investigated. Each of the CBD-ODTs comprised CBD liquisolid powder (10 mg CBD), superdisintegrant, flavors, lubricant, and filler. The physical mixture (PM) ODT was prepared as a control. Ethanol-based ODTs (CBD-EtOH-ODTs) had comparable tablet properties and stability to CBD-PM-ODTs. ODTs with nonvolatile-vehicle-based liquisolid powder had lower friability but longer disintegration times as compared with CBD-PM-ODTs and CBD-EtOH-ODTs. Compression pressure influenced the thickness, hardness, friability, and disintegration of the ODTs. With a suitable compression pressure to yield 31-N-hardness-ODTs and superdisintegrant (4-8%), CBD-ODTs passed the friability test and promptly disintegrated (≤25 s). Times to dissolve 50% of CBD-PM-ODTs, CBD-EtOH-ODTs, and nonvolatile-vehicle-based CBD-ODTs were 10.1 ± 0.7, 3.8 ± 0.2, and 4.2 ± 0.4-5.0 ± 0.1 min, respectively. CBD-EtOH-ODTs exhibited the highest dissolution efficiency of 93.5 ± 2.6%. Long-term and accelerated storage indicated excellent stability in terms of tablet properties and dissolution. Nonvolatile-vehicle-based CBD-ODTs exhibited a higher percentage of remaining CBD. This study provides useful basic information for the development of ODT formulations using a liquisolid technique application.

In Vitro Release, Mucosal Permeation and Deposition of Cannabidiol from Liquisolid Systems: The Influence of Liquid Vehicles

This work investigated the influence of liquid vehicles on the release, mucosal permeation and deposition of cannabidiol (CBD) from liquisolid systems. Various vehicles, including EtOH, nonvolatile low- and semi-polar solvents, and liquid surfactants, were investigated. The CBD solution was converted into free-flowing powder using carrier (microcrystalline cellulose) and coating materials (colloidal silica). A physical mixture of the CBD and carrier–coating materials was prepared as a control. The non-crystalline state of CBD in the liquisolid systems was confirmed using XRD, FTIR and SEM studies. The CBD liquisolid powder prepared with volatile and nonvolatile solvents had a better CBD release performance than the CBD formed as the surfactant-based and control powders. The liquisolid systems provided the CBD permeation flux through porcine esophageal mucosa ranging from 0.68 ± 0.11 to 13.68 ± 0.74 µg·cm⁻²·h⁻¹, with the CBD deposition levels of 0.74 ± 0.04 to 2.62 ± 0.30 μg/mg for the dry mucosa. Diethylene glycol monoethyl ether showed significant CBD permeation enhancement (2.1 folds) without an increase in mucosal deposition, while the surfactants retarded the permeation (6.7–9.0 folds) and deposition (1.5–3.2 folds) significantly. In conclusion, besides the drug release, liquid vehicles significantly influence mucosal permeation and deposition, either enhanced or suppressed, in liquisolid systems. Special attention must be paid to the selection and screening of suitable liquid vehicles for liquisolid systems designed for transmucosal applications.

Mucosal Delivery of Cannabidiol: Influence of Vehicles and Enhancers

In this study, the mucosal permeation and deposition of cannabidiol (CBD) with neat and binary vehicles were investigated. Permeation experiments were performed using static diffusion cells coupled with fresh porcine esophageal mucosa. The CBD-vehicle solutions were applied at a fixed dose (~5 mg/cm²), and the corresponding permeation parameters were calculated. In neat vehicles, the permeation flux (J_ss) ranged from 0.89 ± 0.15 to 179.81 ± 23.46 µg·cm^-2·h^-1, while the CBD deposition ranged from 11.5 ± 1.8 to 538.3 ± 105.3 μg·cm^-2. Propylene glycol (PG) and diethylene glycol monoethyl ether (DEGEE) yielded the highest permeability (P_s) and CBD deposition, while medium-chain triglycerides (MCT) yielded the lowest P_s and deposition. This was due to the difference in apparent partition coefficient (K), which is related to the solubility of CBD in the vehicle. The PG:DEGEE binary vehicle boosted J_ss (1.5-1.6 fold) and deposition (2.0-2.7 folds) significantly, compared to neat DEGEE. The combination of DEGEE with MCT dramatically enhanced J_ss (11-44 fold) and deposition (1.6-4.7 fold). The addition of lipophilic enhancers, laurocapram, and oleic acid, to PG:DEGEE and DEGEE:MCT vehicles significantly reduced J_ss (0.3-0.7 fold) and deposition (0.4-0.8 fold) while nerolidol had no effect. These permeation reductions were found to be related to modification of the K and/or diffusivity values. This study provides useful basic information for the development of CBD formulations intended for transmucosal delivery.

Combining Liquisolid and Co-grinding Techniques to Enhance the Dissolution Rate of Celecoxib

Purpose

The classic liquisolid technique is used to enhance the dissolution rate of poorly water-soluble drugs, but in some cases, it is impossible to reach the desired dissolution rate using this technique alone. Therefore, a novel approach using a combination of ball milling and liquisolid technology was investigated to improve the dissolution rate for celecoxib.

Methods

First, celecoxib was dispersed in a liquid vehicle (PEG 200), then ground in a ball mill for 3 h. Other excipients, including PVP, microcrystalline cellulose as the carrier powder, and silica as the coating material, were added to the mortar. Dissolution testing was carried out in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF) media. The effects of aging on the hardness and dissolution profile were also studied. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) was used to identify changes in the crystallinity or complex formation.

Results

The novel formulations showed a higher dissolution rate than the conventional tablet or classic liquisolid formulations. Aging did not affect the hardness and dissolution profiles of the liquisolid compacts. The DSC and XRD results suggested that the enhanced dissolution rate is not caused by the formation of any complexes and reduction in crystallinity degree may contribute to the dissolution enhancement. The enhanced dissolution rate is attributed to the elevated specific surface area of the drug in the liquisolid state.

Conclusion

The results showed that liquisolid technology combined with ball milling is an efficient tool for enhancing the dissolution of poorly water-soluble drugs.

Multifunctional Role of Silica in Pharmaceutical Formulations

Due to the high surface area, adjustable surface and pore structures, and excellent biocompatibility, nano- and micro-sized silica have certainly attracted the attention of many researchers in the medical fields. This review focuses on the multifunctional roles of silica in different pharmaceutical formulations including solid preparations, liquid drugs, and advanced drug delivery systems. For traditional solid preparations, it can improve compactibility and flowability, promote disintegration, adjust hygroscopicity, and prevent excessive adhesion. As for liquid drugs and preparations, like volatile oil, ethers, vitamins, and self-emulsifying drug delivery systems, silica with adjustable pore structures is a good adsorbent for solidification. Also, silica with various particle sizes, surface characteristics, pore structure, and surface modification controlled by different synthesis methods has gained wide attention owing to its unparalleled advantages for drug delivery and disease diagnosis. We also collate the latest pharmaceutical applications of silica sorted out by formulations. Finally, we point out the thorny issues for application and survey future trends pertaining to silica in an effort to provide a comprehensive overview of its future development in the medical fields. Graphical Abstract.