Beholder ★ Russia, 20171130 16:14 (2015 d 17:46 ago) Posting: # 18027 Views: 6,297 

Hi to everybody! May be it is a strange question, but nevertheless: using which LLOQ the chances to establish BE are higher: higher (5 ng/ml) or lower (0.5 ng/ml)? Thx in advance — Best regards Beholder 
cakhatri ★ India, 20171204 10:52 (2011 d 23:09 ago) @ Beholder Posting: # 18033 Views: 5,541 

Hi, Any LLOQ you select, should be based on justification. In general it is 1/32 of the reported Cmax (Cmax*1/32). This is assumed based on the standard calculation of 5 half lives and usually will be sufficient. Regarding which Cmax to select  You should consider the reported Cmax or if range is available, consider the lower range (if 80100 ng/mL Cmax, consider 80 and calculate 1/32) You also should look at the sampling time points in protocol. if that is beyond 5 half lives, the LLOQ should be lowered accordingly If you are conducting a study with truncated design, the LLOQ need not be 1/32 but higher (1/16 or 1/8) because usually for truncated design the sampling is restricted to 1 or 2 half life and hence LLOQ can be taken higher. With proper selection of LOQ, you will be able to minimize the BLQ (Below limit of Quantification) values and proper estimation of AUC0t and AUC0inf. Regards Chirag 
BEproff ● 20171207 10:25 (2008 d 23:35 ago) @ cakhatri Posting: # 18040 Views: 5,362 

Hi Chirag, Where did you take ratio 1/32? From a guide or from your experience? Prof 
mittyri ★★ Russia, 20171207 16:57 (2008 d 17:04 ago) @ BEproff Posting: # 18042 Views: 5,401 

Dear BEproff, I suppose 2^5 = 32 1/2^5 = 1/32 So Chirag is referring to 5half lives rule (I do not discuss its applicability here) — Kind regards, Mittyri 
cakhatri ★ India, 20171211 08:39 (2005 d 01:22 ago) @ mittyri Posting: # 18054 Views: 5,342 

Hi, That's correct. 1/32 is equivalent to 5 half life Regards Chirag 
xtianbadillo ☆ Mexico, 20180118 16:51 (1966 d 17:10 ago) @ cakhatri Posting: # 18215 Views: 4,987 

As Cakhatri said a proper LLOQ let you a proper estimation of AUC0t and AUC0inf and to avoid BLQ. "for bioequivalence studies the LLOQ should be not higher than 5% of the Cmax, while such a low LLOQ may be not necessary for exploratory pharmacokinetic studies EMA" for BE at least 80% of AUC0inf is required, so a low LLOQ is recommended. In my experience I go for 2SD of the Cmax and the result result is divided by 20: For instance Cmax 1000 +/100, so 800/20 = LLOQ = 40; in this example, according to EMA should be not higher than 50, so 40 is OK Doing this I have reduced my BLO; 1000/32 = 31.25 is better than 40 