Vin nn phenobarbital

Tabellae Phenobarbitali

Vin nn Gardenal, Luminal

 

L vin nn cha phenobarbital.

Ch phm phi p ng cc yu cu trong chuyn lun Thuc vin nn (Ph lc 1.20) v cc yu cu sau y:

Hm lng phenobarbital, C12H12N2O3, t 90,0 n 110,0% so vi hm lng ghi trn nhn.

Tnh cht

Vin mu trng.

 

nh tnh

A. Ly mt lng bt vin tng ng khong 60 mg phenobarbital lc vi 50 ml cloroform (TT) v lc. Bc hi dch lc n kh ri sy kh 105 oC trong 2 gi. Ph hng ngoi (Ph lc 4.2) ca cn phi tng ng vi ph hng ngoi ca phenobarbital i chiu.

B. Trong phn nh lng, thi gian lu ca pic chnh trn sc k ca dung dch th phi tng ng vi thi gian lu ca pc phenobarbital trn sc k dung dch chun.

 

ho tan

Thit b : Kiu cnh khuy.

Mi trng ho tan: 900 ml nc.

Tc quay: 50 vng/pht.

Thi gian: 45 pht.

Cch tin hnh: Ly mt phn dung dch sau khi ha tan, lc, b 20 ml dch lc u. o hp th (Ph lc 4.1) ca dch lc thu c bc sng cc i khong 240 nm. So snh vi dung dch chun c nng phenobarbital tng ng dung dch th v c lm song song; c th pha long dch th bng dung dch m borat pH 9,6 (TT) (nu cn) (Dung dch m borat pH 9,6 c iu ch bng cch ho tan 2,474 g acid boric (TT) v 2,982 g KCl (TT) v 36,9 ml dung dch NaOH 0,2N (TT) trong nc va 200,0 ml). Tnh hm lng phenobarbital ha tan da vo cc hp th o c v nng phenobarbital trong dung dch chun.

Yu cu: Khng c t hn 75,0% lng phenobarbital so vi lng ghi trn nhn c ho tan trong 45 pht.

 

nh lng

Tin hnh bng phng php sc k lng (Ph lc 5.3)

Dung dch m pH 4,5: Ho tan 6,6 g natri acetat trihydrat (TT) v 3,0 ml acid acetic bng (TT) trong 1000 ml nc, iu chnh n pH 4,5 0,1 bng acid acetic bng (TT).

Pha ng: Hn hp ca dung dch m pH 4,5 v methanol (3 : 2 ).

Dung dch ni chun: Ho tan cafein trong hn hp ng th tch methanol (TT) v dung dch m pH 4,5 c nng cafein khong 125 mg/ml.

Dung dch chun: Ho tan mt lng chnh xc khong 20,0 mg phenobarbital chun trong 15,0 ml dung dch ni chun, lc siu m nu cn, lc qua mng lc 0,45 mm.

Dung dch th: Cn 20 vin, tnh khi lng trung bnh vin v nghin thnh bt mn. Cn chnh xc mt lng bt vin tng ngkhong 20 mg phenobarbital, thm 15,0 ml dung dch ni chun, lc siu m trong 15 pht, lc qua mng lc 0,45 mm.

iu kin sc k: Ct thp khng g (25 cm 4 mm) c nhi pha tnh C (3-10 mm).

Detector quang ph hp th t ngoi bc sng 254 nm.

Tc dng: 2,0 ml/pht.

Th tch tim: 10 ml.

Cch tin hnh:

Kim tra kh nng thch hp ca h thng sc k: Tin hnh sc k vi dung dch chun, phn gii gia pic phenobarbital v cht chun ni khng c nh hn 1,2; h s i xng ca pic phenobarbital v pic ni chun khng c ln hn 2,0 v lch chun tng i ca cc ln tim lp li khng c qu 2,0%. Thi gian lu tng i ca cafein khong 0,6 v ca phenobarbital l 1,0. C th iu chnh thnh phn pha ng t iu kin trn.

Tin hnh sc k ln lt vi dung dch chun v dung dch th .

Tnh hm lng phenobarbital, C12H12N2O3, trong mt vin da vo din tch pic trn sc k ca dung dch chun, dung dch th v hm lng C12H12N2O3 trong phenobarbital chun.

 

Bo qun

Trong ng kn, trnh nh sng.

 

Loi thuc

Chng co git v an thn, gy ng.

 

Hm lng thng dng

10mg, 50 mg, 100 mg.