Accuspin 17r centrifuge

The drug content and loading in the TA-SLNs was determined by using the lipid precipitation method where, at first, the lipid in the SLN and SLN-IG (0.1 mL) was precipitated using 0.9 mL of methanol, followed by centrifugation (AccuSpin 17R centrifuge, Fisher Scientific, Hanover, IL, USA) under 13,000 rpm for 15 min and analyzing the supernatant using HPLC.
Drug loading in SLNs were calculated using following formula: where Wt is the total weight of the drug, Wu is the weight of the unentrapped drug, and W_L is the weight of the lipids.
The EE(%) in TA-SLNs were calculated by estimating the concentration of the free drug in the aqueous phase of an undiluted formulation, using an ultrafiltration method with 100-kDa centrifugal filter unit (Amicon Ultra, Hanover, IL, Fisher Scientific, USA). Briefly, a 500 uL aliquot of the formulation was added to the filter unit and centrifuged under 13,000 rpm for 15 to 20 min. The filtrate was further diluted and analyzed for the drug content using HPLC-UV system. The EE was calculated by using the Equation (2): $\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$0$}\right.\mathrm{EE}=\left[\frac{\mathrm{Di}-\mathrm{Df}}{\mathrm{Di}}\right]{\times }^{\begin{array}{c}\\ 100\end{array}}$ where D_i is the total drug content and D_f is the free drug present in the aqueous phase.

CIP content in the CIP-NLCs was determined using the lipid precipitation method wherein an accurately measured volume of the NLCs (10 μL) was extracted in a 1:1 binary mixture of 0.1N HCl and 200 proof alcohol (990 μL). The mixture was centrifuged (AccuSpin 17R centrifuge, Fisher Scientific, Waltham, MA, USA) at 13,000 rpm for 20 mins, and the supernatant was analyzed for CIP content, using the HPLC method described above, following appropriate dilution. The CIP content (assay) was used to calculate the percentage entrapment efficiency (%) of CIP in the CIP-NLCs.

Fifty microliters (50 μL) of the CBD-NE and CBD-NEC formulations were transferred into a volumetric flask (5 mL) and the volume was adjusted with acetonitrile (extracting solvent, 100-fold dilution). The extract was vortexed (5 min, 2000 rpm, Vortex-Genie^® 2, Scientific Industries, Inc., Bohemia, NY, USA) and sonicated (Bransonic^® ultrasonic cleaner, Branson Ultrasonics corporation, Brookfield, CT, USA) for 10 min. The extract was then centrifuged (AccuSpin 17R centrifuge, Fisher Scientific, Hanover, IL, USA) for 20 min at 13,000 rpm. Then, the supernatant was diluted (10-fold) with acetonitrile before being analyzed for CBD content using the HPLC method mentioned above.