1378 BRITISH MEDICAL JOURNAL 5 JUNE 1976 Talampicillin: a new derivative of ampicillin Br Med J: first published as 10.1136/bmj.1.6022.1378 on 5 June 1976. Downloaded from D A LEIGH, D S REEVES, KATE SIMMONS, A L THOMAS, P J WILKINSON British Medical3Journal, 1976, 1, 1378-1380 ampicillin either after an overnight fast, or within 45 minutes of a standard breakfast. Serum levels were measured one, two, four, six, and eight hours after the dose and all urine was collected for two Summary consecutive six-hour periods and the subsequent 12-hour period. Thirteen patients treated with 750 mg of talampicillin twice daily Talampicillin is a thiazolide carboxylic ester of ampicillin had serum concentrations monitored after their first dose, which was and is hydrolysed in the intestinal mucosa to release variably related to their last meal. Most patients in the clinical trial free ampicillin. The mean peak serum concentration (see below) had urinary concentrations and total recoveries measured ofampicillin occurred one hour after a dose of talampicil- for the first 48 hours of treatment. In all studies ampicillin was lin and was about twice that attained by an equivalent assayed by a plate diffusion method using the Oxford staphylococcus (NCTC 6571) (at High Wycombe) or Bacillus subtilis (NCTC 6633) dose of ampicillin. The presence of food in the stomach (at Bristol) as the indicator strain. reduced and delayed the peak blood levels but did not affect the total amount of antibiotic absorbed or the urinary recovery. Talampicillin had less effect on the faecal flora in volunteers than ampicillin, and no over- FAECAL FLORA STUDY growth with Candida spp or Staphylococcus aureus was Ten healthy volunteers took 250 mg of talampicillin four times a seen. Thirty-eight out of 47 urinary infections were day for two days. Specimens of faeces collected into containers under eradicated by a seven-day course of talampicillin. liquid paraffin on the day before starting and the day of stopping treatment were examined within 30 minutes. Ten days later the procedure was repeated with the same dose of ampicillin. After each Introduction treatment the volunteers were asked about the effect of the antibiotic and the occurrence of any side effects. The faeces were cultured to determine the total counts of aerobic Since its introduction in 1964 ampicillin has successfully treated and anaerobic organisms, and the counts of Candida spp and Staphyl- many types of bacterial infection, but gastrointestinal side effects ococcus aureus. A standard volume of faeces, roughly equivalent to 1 g have been reported in up to 20O' of patients.' The phthalidyl weight, was disintegrated in 5 ml of Brewer's broth. Serial hundred- thiazolidine carboxylic ester of ampicillin, talampicillin (Talpen, fold dilutions were made in Brewer's broth, and surface viable counts Beecham), has been introduced recently to improve absorption from 0 l-ml inocula were carried out on blood, MacConkey, salt and to reduce these side effects. After oral administration mannitol, and a selective yeast agar, all incubated aerobically. They talampicillin is rapidly absorbed and hydrolysed by tissue estera- were also inoculated on to blood agar containing vitamin K and ses in the intestinal wall to release into the circulation ampicillin haemin, with or without neomycin (01 g/l), and incubated anaero- and the ester moiety, mainly 2-hydroxymethyl-benzoic acid. No bically by the Gaspak method. Colonies were counted after one and unchanged talampicillin is detectable in the peripheral blood.2 two days' incubation and speciated by routine laboratory methods. In common with other thiazolidine esters of pencillins3 talampi- http://www.bmj.com/ cillin has no intrinsic antibacterial activity and should have no direct effect on the bacterial flora of the intestinal tract. CLINICAL TRIAL We compare here some pharmacological properties of talampi- and of oral Forty-seven patients with urinary infection were treated with cillin with those of ampicillin report the effects talampicillin for seven days at a dosage of 390 mg three times daily administration of each drug on the faecal bacterial flora. We also (at Wycombe) or 750 mg twice daily (at Southmead). Infection was performed a clinical trial of talampicillin in urinary infections confirmed by a pure growth > 105 organisms/ml of a single species in at two centres (Wvcombe General Hospital and Southmead two consecutive urinary cultures. All isolates were sensitive to Hospital). ampicillin on initial laboratory disc testing. Further specimens were on 4 October 2021 by guest. Protected copyright. examined at one and three or five weeks after stopping treatment. Reinfection was distinguished from failure of eradication by antigenic Methods typing where appropriate (Esch coli) and Dienes' typing (Proteus spp). The patients gave informed consent; those with a history of PHARMACOLOGICAL STUDIES penicillin allergy or renal or hepatic insufficiency were not included. All patients were interviewed about the occurrence of side effects, and The serum and urine concentrations resulting from a single 390-mg haematological and biochemical indices were measured before and dose of talampicillin * were determined in 10 healthy fasting volunteers. after treatment. Samples of blood were taken 30 minutes and one, two, four, and six hours after the dose, and urine was collected for four two-hour periods. The effect of food on absorption was determined by a crossover study in which four volunteers took 500 mg of talampicillin or Results SERUM AND URINE CONCENTRATIONS *Ratio equivalent of talampicillin to ampicillin 1-5:1. The mean peak ampicillin concentration of 5 4 mg/l in the serum of the 10 fasting volunteers occurred one hour after the 390 mg dose of talampicillin (fig 1). Appreciable concentrations were present at Wycombe General Hospital, High Wycombe, Bucks HP11 2TT 30 minutes and six hours. In 13 inpatients who received 750 mg of D A LEIGH, MB, BS, consultant microbiologist talampicillin the mean peak concentration at one hour was 9 4 mg/l KATE SIMMONS, AMILS, research technician (fig 1), though individual results were more scattered than among the General Bristol 5NB volunteers. Southmead Hospital, BS10 In the crossover study peak serum concentrations of ampicillin D S REEVES, MB, MRCPATH, consultant microbiologist were more than twice as high after talampicillin than after ampicillin A L THOMAS, MB, MRCP, research registrar (now registrar in renal (fig 2). The mean peak (fasting) level was 5-2 mg/l after 500 mg of medicine, Cardiff Royal Infirmary, Cardiff CF2 lSZ) same dose of in P J WILKINSON, MB, BCHIR, senior registrar in medical microbiology talampicillin and 2-7 mg/l after the ampicillin. Food the stomach delayed the peak but did not affect urinary recoveries of BRITISH MEDICAL JOURNAL 5 JUNE 1976 1379 25 - 390mg ( _ 263mg PFA) in in either of the volunteer groups. The mean urinary ampicillin 10 healthy subjects concentration in the patients was 286 mg/l (range 67-1026 mg/i). --- 750mg in (-500mgqPFA) Br Med J: first published as 10.1136/bmj.1.6022.1378 on 5 June 1976. Downloaded from 20- 13 patients 0' FAECAL FLORA STUDY E I5 I15 The results of culture of the pretreatment faecal specimens before both talampicillin and ampicillin in the 10 volunteers were similar, U T 0. and in the four groups of bacteria studied the counts were within E 1 log difference for each volunteer. Overall, the total anaerobic 0 E counts were between 109 and 1011 organisms per gram of faeces, but 36 the total aerobic counts showed more individual variation, six volun- 5. teers having counts of 104 to 106 organisms per gram of faeces, but four having consistently lower counts of about 5 x 103 organisms. The Candida counts were always below 5 x 103 before treatment, but 0 with Staph aureus there was a range of 5 x 103 to 105 organisms. 0 05 2 4 6 Hours u FIG 1-Mean serum concentrations and ranges of ampicillin after single doses of talampicillin in volunteers and patients. PFA = Pure free acid. 80 0 -- Non-fasting -o1- - Fastinq Ampicilli n Talampicil in 0 60 8 500mg 50Cmg (-338mg PFA) 1-- ._. -- Non-fasting @ 40 - ~Fasting u > 0I ._. 20 S E- 0 0 0-b -12 -24 0 2 4 6 8 0 2 4 6 8 Hours Hours FIG 3-Mean cumulative urinary excretion and ranges of ampicillin in four healthy subjects after single oral dose of ampicillin or talampicilhin. PFA = FIG 2-Mean serum ampicillin concentrations and ranges in four healthy Pure free acid. subjects after single oral dose of ampicillin or talampicillin. PFA = Pure free acid. Four of the volunteers taking talampicillin showed little change in the counts of the four groups of bacteria (table I). Five showed a ampicillin (fig 3), which were 520, (fasting) and 59O% (after food) considerable increase in total aerobic counts (in four cases due to the http://www.bmj.com/ after talampicillin and 26% (fasting) and 230% (after food) after presence of ampicillin-resistant strains of Enterobacteriaceae) and ampicillin. two had a reduction in total anaerobic counts. Urine concentrations of ampicillin in the 10 fasting volunteers were With ampicillin the changes were more striking. The bacterial high with a mean peak of 800 mg/l (range 200-1500) in the first two counts in eight volunteers changed considerably (table I); in three the hours of collection. Altogether 47% of the administered dose was total aerobe count increased owing to resistant strains of Entero- recovered in six hours. The mean total antibiotic recovery in 40 patients bacteriaceae, and in four the total Candida count rose considerably. in the trial was 42% (range 9-790%) and showed greater variation than The total anaerobe count fell in four volunteers, one ofwhom developed on 4 October 2021 by guest.