New spectrophotometric microdetermination of carbapenem antibiotics derivatives in pharmaceutical formulations

Peer review under responsibility of Taibah University

Figures & data

Fig. 1 Chemical structures of imipenem (1), meropenem (2), and ertapenem (3).

Fig. 2 Absorption spectra of Phen and Bip complexes in presence of 4.0 μg mL⁻¹ imipenem.

Fig. 3 Effect of pH and reagent concentration on the absorbance of the [Phen] and [Bip] complexes in presence of 4.0 μg mL⁻¹ Imipenem.

Fig. 4 Effect of temperature and reaction time on the absorbance of [Phen] and [Bip] complexes in presence of 4.0 μg mL⁻¹ Imipenem.

Table 1 Characteristics of different calibration graph for carbapenem derivatives by developed Phen and Bip methods.

Parameter	Units	Imipenem		Meropenem		Ertapenem
		Phen	Bip	Phen	Bip	Phen	Bip
Wavelength	(nm)	510	520	510	520	510	520
Beer’s concentration range	(μg mL^−1)	0.2–10.0	0.2–10.0	0.5–10.0	0.5–10.0	0.5–10.0	0.5–10.0
Ringbom concentration range	(μg mL^−1)	0.35–9.5	0.33–9.7	1.05–8.7	1.2–8.8	0.5–9.0	0.52–9.4
Detection limits	(μg mL^−1)	0.064	0.055	0.042	0.074	0.112	0.145
Quantification limits	(μg mL^−1)	0.211	0.176	0.139	0.244	0.358	0.435
Molar absorpitivity	×10^4 (L mol^−1 cm^−1)	5.60	3.50	7.00	5.75	8.70	6.58
Sandell sensitivity	(μg cm ^−2)	0.0142	0.0128	0.0247	0.01976	0.0227	0.0176
Regression equation	(Y = a + bX)^a
Slope (b)		0.175	0.114	0.1691	0.13708	0.17315	0.12111
S.D. of slope (Sb)		3.76 × 10^−3	2.10 × 10^−3	0.00238	0.00339	0.00648	0.00587
Intercept (a)		5.08 × 10^−2	2.80 × 10^−2	0.05416	0.0346	0.08571	0.08065
S.D. of intercept (Sa)		1.80 × 10^−4	1.00 × 10^−3	0.0238	0.01785	0.0341	0.03086
Correlation coefficient		0.9984	0.9988	0.9979	0.9982	0.9958	0.9930
Calculated t-values (2.57)^b		1.07	0.70	1.10	0.80	1.03	0.74
Calculated F-test (5.05)^a		2.37	2.13	2.47	2.22	2.52	2.19

a Y = a + bX, where Y is the absorbance of the coloured complex and X is the concentration of drug in μg mL⁻¹.

b Values in parentheses are the theoretical values for t- and F-value at 95% confidence limits and five degrees of freedom.

Fig. 5 Spectrophotometric determination of imipenem using [Phen] and [Bip] complexes at the optimum experimental conditions.

Table 2 Accuracy and precision of the proposed methods for analysis of imipenem (n = 5).

Method	Taken (μg mL^−1)	Found (μg mL^−1)
		Within-assays			Between-assays
		Found (μg mL^−1)	Recovery (%)	RDS (%)	Found (μg mL^−1)	Recovery (%)	RDS (%)
Phen	1.0	0.95	95.00	0.88	0.97	97.00	1.25
	3.0	2.86	95.33	0.78	3.12	104.00	0.95
	5.0	4.78	95.60	1.10	4.92	98.40	0.98
	8.0	7.89	98.63	0.95	7.91	98.88	1.25
Bip	1.0	1.01	101.00	0.65	0.99	99.00	0.66
	3.0	3.02	100.66	0.75	2.92	97.33	0.77
	5.0	5.10	102.00	1.05	4.85	97.00	0.96
	8.0	7.93	99.12	0.82	7.88	98.50	0.74

Table 3 Determination of carbapenem in pharmaceutical preparations by the proposed and official method.

Sample	Recovery
	Phen	Bip	Official method
Tienam (500 mg)	Recovery 100.8 ± 1.0	Recovery 98.9 ± 1.3	Recovery 99.6 ± 1.3
	Variance 0.71	Variance 0.59
	F* 2.82	F 2.53
	t* 1.93	t 0.55
Meronem (500 mg)	Recovery 99.8 ± 0.61	Recovery 101.7 ± 0.92	Recovery 101.0 ± 1.0
	Variance 0.55	Variance 0.49
	F = 1.74	F 2.03
	t = 0.73	t 0.92
Invanz (1.0 g)	Recovery 99.4 ± 0.80	Recovery 100.6 ± 0.9	Recovery 100.0 ± 1.4
	Variance 0.44	Variance 1.05
	F 3.13	F 3.05
	t 0.88	t 1.22