[Experimental study of an ampicillin suppository (KS-R1) in adults and children].

KS-R1, a new rectal suppository of ampicillin (ABPC) sodium, was compared with oral and parenteral ABPC in terms of absorption and excretion in childish patients and healthy adult male volunteers. In addition, the irritation of KS-R1 to the rectum was studied. 1. Eight healthy adult male volunteers received 250 mg (potency) of KS-R1 rectally and 125 mg of ABPC intravenously in a cross-over study. Then, 4 of them were given intramuscularly 250 mg of ABPC, and 3 of the remaining 4 volunteers were given 250 mg of ABPC orally. The rectal administration of 250 mg of KS-R1 resulted in a mean peak ABPC plasma level (Cmax) of 2.6 mcg/ml at 30 minutes, and then ABPC levels declined with biological half-life (T2/1) of 0.55 hour. The peak time (Tmax) of occurrence after rectal dose of KS-R1 was earlier than that after oral dose of ABPC, and was equal to that after intramuscular dose of ABPC. Cmax after rectal dose of KS-R1 was equal to that after the oral dose, and was about 40% of the value attained with the intramuscular dose. Urinary recovery of ABPC during 6 hours after rectal dose of KS-R1 was 24.0%, compared with 34.0% for the oral dose, 59.6% for the intramuscular dose and 61.4% for the intravenous dose. The relative bioavailability of KS-R1, calculated on the basis of urinary recovery after intravenous administration of ABPC, was about 40%. 2. When KS-R1 (250 mg) was given to 2 adult volunteers 3 times daily for 5 days, no remarkable difference was found in plasma concentration and urinary recovery of ABPC. The pharmacokinetic parameters following the last administration were similar to those following a single administration of KS-R1. 3. KS-R1, oral ABPC and intravenous ABPC were administered at the dose of 125 mg (potency) to 5, 4 and 3 children and at the dose of 250 mg (potency) to 5, 3 and 3 children, respectively. Peak plasma level (Cmax) of ABPC after rectal administration of 125 mg and 250 mg of KS-R1 was reached in 15 minutes, indicating 4.8 and 7.1 mcg/ml, respectively. Peak time (Tmax) of ABPC after the rectal doses of KS-R1 was about 2 hours earlier than that after oral doses of ABPC. Cmax after KS-R1 was 3-4 times as high as that after the oral doses. Area under the curve (AUC) with KS-R1 was 1.38-1.55 times greater than that of oral ABPC, and about 24% of the values obtained with intravenous doses of ABPC. Urinary recoveries of ABPC rectal doses of KS-R1 were 30.4 to 45.6%, compared with 29.2 to 30.8% for the oral doses and 61.1 to 76.1% for the intravenous doses.(ABSTRACT TRUNCATED AT 400 WORDS)