(I wonder if we can avoid the excessive stirring and get smaller particles by dissolving the resveratrol in everclear before adding to a standard lecithin/water emulsion)
Here's the section of interest:
Example 9
Preparation of Resveratrol Cyclodextran Solutions and Lyophilized Powders
[1344] Two resveratrol formulations were chosen for evaluation as prototype drug products, resveratrol solutions in either 40% Captisol or 10% Captisol. Specifically, a low concentration resveratrol solution (20 mM or 4.57 mg/mL) in 10% Captisol (w/v) was produced on a 20 mL scale and lyophilized vials produced (1 mL per vial). Lyophilized vials containing 10% Captisol control vehicle were also manufactured. A high concentration resveratrol solution (150 mM) in 40% Captisol (w/v) was produced on a 500 mL scale, and supplied as a lyophilized product (5 mL per vial). Lyophilized vials containing 40% Captisol control vehicle were also manufactured.
[1345] The low concentration resveratrol solution was prepared by adding 136.99 mg resveratrol to 30 mL 10% Captisol (CyDex, Lot # CY-04A-05006), and mixed for 1 hour at ambient temperature. The initial solution had a pH of 5.02 and with a concentration of 15.4 mM in resveratrol. The solution was filtered through a 0.20 .mu.m nylon syringe filter (Fisher #09-719C), resulting in a solution at 14.9 mM in resveratrol with a pH of 4.83. The 10% Captisol control vehicle solution had a pH of 4.78 before filtration and a pH of 4.76 after filtration. The filtered solutions were dispensed into vials (1.0 mL solution into 3 mL vial, Wheaton #223684), and lyophilized. At the end of the lyophilization cycle, the vials were sealed under vacuum and a cap crimped over the septa.
[1346] The lyophilized resveratrol product was an off-white cake. The material reconstituted in .about.20 seconds after the addition of 1.0 mL water. The reconstituted resveratrol solution was clear, with no visible particulates, having a pH of 5.91, and a measured concentration of 14.4 mM resveratrol. The lyophilized control vehicle product was a white cake. The material reconstituted in .about.20 seconds after the addition of 1.0 mL water. The reconstituted control vehicle was clear, with no visible particulates, and having a pH of 5.82.
[1347] The high concentration resveratrol formulation (150 mM SRT501 in 40% Captisol (w/v) on a 500 mL scale) was prepared as follows. A 40% Captisol (w/v) was prepared by placing 560 g of Captisol (CyDex, Lot # CY-04A-05006) into a 4 L beaker. A large stir bar was added to the beaker that was then placed on a large stir plate. In-house Milli-Q water was added to bring the volume in the beaker to .about.1.3 L. The solution was mixed vigorously for 1 hour until clear. At times, a spatula was used to free the stir bar and dislodge undissolved material from the sides of the vessel. The solution was transferred to a 2 L graduated cylinder. Approximately 100 mL of water was used to rinse the beaker and was added to the graduated cylinder, bringing the final volume to 1.4 L. The solution was mixed thoroughly until clear.
[1348] The high concentration resveratrol solution was prepared by mixing 600 mL of 40% Captisol in a 1 L beaker with 24.0 g resveratrol and stirring vigorously (the target concentration would be 175 mM resveratrol in 40% Captisol (w/v) if all the material dissolved). The solution was stirred for 35 minutes, followed by sonication for 1 hour. The solution was stirred for an additional 50 minutes, followed by sonication for an additional hour. At this point, solid material was still present in the sample. An aliquot was removed for analysis. The pH was measured at 4.76 and the concentration was measured by HPLC to be 55 mM resveratrol. Because the solution appeared cloudy at this time, three portions were separated to try alternate mixing methods. Approximately 200 mL was transferred to a 500 mL volumetric flask and was sonicated for 45 min, approximately 300 mL was vigorously mixed with an overhead mixer for 90 minutes, and approximately 100 mL was homogenized for 25 minutes. None of the three portions appeared clear. A sample of the homogenized solution was removed for concentration analysis and had a concentration of 74 mM resveratrol. The portions were combined and were stirred at ambient temperature overnight protected from light. The following morning, using an aseptic technique in the laminar flow hood, the solution was sterile filtered via a Nalgene 90 mm filter unit (Cat# 167-0020; 0.02 PES membrane). The concentration was again measured and determined to be 168 mM resveratrol in 40% Captisol.
[1349] The control vehicle (40% Captisol (w/v)) was also prepared as follows. 700 mL of 40% Captisol was transferred into a 1 L beaker. The solution was sonicated for a total of 2 hours. The solution was then stored at ambient temperature overnight. Using an aseptic technique in the laminar flow hood, the solution was sterile filtered via a Nalgene 90 mm filter unit (Cat# 167-0020; 0.02 PES membrane).
[1350] In the laminar flow hood, 30 mL molded glass vials, which had been sterilized by an autoclave, were filled with 5 mL of control vehicle or resveratrol solution. The vials were lyophilized in three batches according to the previously developed lyophilization cycle. The vials were stoppered under vacuum, sealed, and labeled. The resveratrol/Captisol vials contained a cake with an off-white appearance. The sample quickly reconstituted to a slightly yellow clear solution with the addition of water. 3.7 mL of water should be added to a vial to produce the original concentration of 40% Captisol.
http://www.cydexinc.com/captisol.asp
