Accelerated stability and bioassay of a new oral α-ketoglutarate formulation for treating cyanide poisoning

Figures & data

Figure 1. Accelerated stability analysis of α-ketoglutarate (α-KG) formulation was carried out for a period of 6 months. At the beginning of the experiment (“0” month), absorbance of α-KG was recorded at 240–400 nm. The UV spectrum of α-KG was recorded at 317 nm, while cyanide did not show any absorbance at 240–400 nm. Thereafter, cyanide and α-KG were mixed in 1:1 ratio and the disappearance of α-KG peak was observed, which confirmed the interaction of α-KG and cyanide to produce cyanohydrin complex.

Table 1. Various physical, chemical and microbiological assays carried out during accelerated stability analysis of α-KG formulation.

		Time intervals in months
Stability analysis	Parameters	0	1	2	3	4	5	6
Physical stability analysis	Color and clarity	Yellow and clear	Yellow and clear	Yellow and clear	Yellow and clear	Yellow and clear	Yellow and clear	Yellow and clear
	pH	7.8 ± 0.10	7.8 ± 0.10	7.8 ± 0.15	7.8 ± 0.10	7.8 ± 0.15	7.7 ± 0.20	7.7 ± 0.10
	Evaporation	Nil	Nil	Nil	Nil	Nil	Nil	Nil
	Extractable volume (ml)	100	100	100	100	100	100	100
Chemical analysis	Photometric assay (mg/ml)	109.8 ± 0.50	106.3 ± 0.40	102.6 ± 0.60	98.3 ± 0.35	93.5 ± 0.50	88.1 ± 0.20	83.6 ± 0.20
Microbiological analysis	Total aerobic count	No growth observed	No growth observed	No growth observed	No growth observed	No growth observed	No growth observed	No growth observed

Accelerated stability analysis of α-ketoglutarate (α-KG) formulation was carried out for a period of 6 months. Various physical, chemical and microbiological analyses were performed at different time intervals. Values are mean ± SE of three replicates.

Table 2. Protective efficacy of different doses of α-KG formulation against acute cyanide intoxication in mice.

	Treatment time of α-KG
	0 min		−10 min
Treatments	LD50 of KCN (mg/kg)	PI	LD50 of KCN (mg/kg)	PI
0.15 g/kg α-KG	37.0 (14.6–89.1)	2.96	37.0 (14.6–89.1)	2.96
0.30 g/kg α-KG	73.8 (29.8–182.9)	5.91	73.8 (29.8–182.9)	5.91
0.60 g/kg α-KG	73.8 (29.8–182.9)	5.91	73.8 (29.8–182.9)	5.91
2.0 g/kg α-KG	73.8 (29.8–182.9)	5.91	147.33 (59.5–364.9)	11.78

Accelerated stability analysis of α-ketoglutarate (α-KG) formulation was carried out for a period of 6 months. At the beginning of the experiment (“0” month), protective efficacy of α-KG (oral) formulation was evaluated against potassium cyanide (KCN; oral) in male mice. Acute (24 h) LD₅₀ of KCN was determined in the presence or absence of simultaneous treatment (0 min) or pre-treatment (−10 min) of α-KG given at 0.15 g/kg (low dose), 0.30 g/kg (medium dose), 0.60 g/kg (high dose) and 2.0 g/kg (protective dose). Protection Index (PI) was calculated as the ratio of LD₅₀ of KCN in protected animals and LD₅₀ of KCN in unprotected animals. LD₅₀ of KCN alone was 12.5 (7.7–20.6) mg/kg. Values in parentheses are fiducial limits at 95% confidence interval.

Figure 2. Accelerated stability analysis of α-ketoglutarate (α-KG) formulation was carried out for a period of 6 months. At the beginning of the experiment (“0” month), female rats were administered α-KG (oral) formulation at 0.15 g/kg (low dose), 0.30 g/kg (medium dose), 0.60 g/kg (high dose) and 2.0 g/kg (protective dose). Thereafter, blood α-KG levels were measured at various time intervals. Values are mean ± SE of six animals. *Significantly different from corresponding control at p < 0.05.