Table 8.
Comparison between USP dissolution allicin release (in vitro) and allicin bioavailability (in vivo) for garlic supplements.
| Product | Alliinase Activity 2 | Potential Allicin 3 (mg; % of Claim) | Dissolution Results (In Vitro) | In Vivo Results (LP meal) 1 | |||||
|---|---|---|---|---|---|---|---|---|---|
| Disinteg Ration Time 4 (h) | Allicin Release 5 (mg) | Allicin Release 6 (%) | Allicin Release 7 (% of Claim) | Allicin Bioavailability, RRF (%) | Ratio: 8
In Vivo/In Vitro |
Tmax (h) | |||
| Enteric tablets (rapid in vitro disintegration) | |||||||||
| E1 | 12,650 | 3.92 (123) | 2 + 1 | 3.37 | 86 | 105 | 91 | 1.1 | 4.7 |
| E2 | 2360 | 4.20 (84) | 2 + 0.75 | 3.90 | 93 | 78 | 69 | 0.7 | 4.1 |
| E5 | 520 | 0.85 (nc) | 2 + 1 | 0.71 | 84 | nc | 104 | 1.2 | 3.6 |
| Enteric tablets (slow in vitro disintegration) | |||||||||
| E3 | 1950 | 5.17 (103) | 2 + 2.5 | 0.13 | 3 (12) 9 | 3 | 36 | 12 | 2.6 |
| E4 | 13,500 | 5.45 (76) | 2 + 5.7 | 0.33 | 6 (13) 9 | 5 | 71 | 12 | 3.3 |
| E6 | 550 | 3.31 (66) | 2 + 3.5 | 0.21 | 6 (28) 9 | 4 | 52 | 9 | 6.3 |
| Normal tablets | |||||||||
| N1 | 6520 | 1.65 (92) | 1.5 + 0 | 0.20 | 12 | 13 | 80 | 7 | 3.0 |
| N2 | 360 | 0.27 (nc) | 1.75 + 0 | 0.015 | 6 | nc | 93 | 16 | 2.1 |
| N3 | 10,700 | 11.1 (nc) | 1.75 + 0 | 1.84 | 17 | nc | 111 | 7 | 2.2 |
| Capsules 1 | |||||||||
| C1 | 10,840 | 5.0 (nc) | 2 + 1 | 2.1 | 42 | nc | 54 | 1.3 | 2.3 |
| C2 | 210 | 3.08 (nc) | 2 + 0 | <0.03 | <1 | nc | 26 | >27 | 3.6 |
| C3 | 250 | 1.27 (170) | 0.25 + 0 | <0.03 | <1 | <4 | 109 | >109 | 3.8 |
1 The in vivo results for allicin bioavailability (RRF) and Tmax are from Table 6. All products were consumed with the low-protein (LP) meal, except C3 was consumed with the high-protein (HP) meal. 2 Alliinase activity is expressed as μg allicin min−1 g−1 garlic powder content. 3 Potential allicin (allicin potential): allicin found (mg/tablet or capsule) after pulverized tablets or capsule contents were stirred in water for 30 min; it is also given as % of label claim reported in Table 1, except when there was no claim (nc) for allicin. 4 Time to achieve complete disintegration in the dissolution test. The first 2 h was in acid; the remaining time was in buffer. Values are the average of two tests. 5 Dissolution allicin release (mg): allicin found (mg/tablet or capsule) at the United States Pharmacopeia (USP) standard time of 1 h in buffer, after 2 h in acid. Values are the average of two tests. 6 Dissolution allicin release (%): allicin found, as percent of potential allicin, at the USP standard time of 1 h in buffer, after 2 h in acid. 7 Dissolution allicin release (% of claim): dissolution allicin release (mg) compared to label claim (Table 1), except when there was no claim (nc). 8 Ratio (in vivo/in vitro): allicin bioavailability (%)/dissolution allicin release (%). 9 Dissolution allicin release (%), at the time of complete disintegration, when greater than 1 h in buffer.