TABLE 5.

Quantification of enzymatic degradation of meropenem products by mDHP-I, determined by HPLC-UV and microbiological assay^a

Assay and reaction time (h)	Fraction of initial meropenem concn remaining (%)
	Control	Initial 125 mg/liter		Initial 250 mg/liter		Initial 500 mg/liter
		iMer	gMer-A	iMer	gMer-A	iMer	gMer-A
HPLC-UV
0.08	99	89	65	86	48	96.4	51
0.5	98.3	87	63	82	44	94	47
1.0	96	49	25	39	26	73	37
1.5	96	23	17	27	14	57	8
4.0	92	10	10	8	8.4	41	0
4.5	92	10	8	6	4	0	0
Microbiological assay
0.08	96	92	45	88	45	89	64
0.5	94	94	45	88	43	89	60
1.0	94	64	30	31	17	35	14
1.5	94	48	23	20	12	22	17
4.0	88	15	0	6	6	7	5
4.5	88	0	0	6	6	5	5

^aThe enzymatic reaction was allowed to take place for 5 min at 37°C before taking the first sample for analysis; the control sample (iMer, 500 mg/liter) was incubated in sterile saline without the enzyme. The data are presented as the percentage of each initial concentration of meropenem (125, 250, or 500 mg/liter).