Table 2 Different orders of degradation reaction and formulas for calculating kinetic parameters

Zero-order

\(R = \frac{{ - {\text{d}}\left\lceil A \right\rceil }}{{{\text{d}}t}} = k_{0}\)

t_1/2 = [A]₀ /2 k

t_0.9 = 0.1[A]₀/k₀

Hydrolysis of atorvastatin

Electrochemical degradation ceftriaxone

Ahmad et al. (2006), Ahmad and Vaid (2011), Aulton and Taylor (2007), de Haro Moreno and Salgado (2012), Jain et al. (2011), Oliveira et al. (2013), Robnik et al. (2019), Shubha and Sushma (2015) and Tutunaru et al. (2021)

First-order

\(R = \frac{{ - {\text{d}}\left\lceil A \right\rceil }}{{{\text{d}}t}} = kA\)

t_1/2 = ln(2)/k

t_0.9 = 0.105/ k₁

Oxidation of butacaine

Oxidation of benzocaine hydrochloride

Hydrolysis of atorvastatin

Thermal and photodegradation of ceftazidime

Second-order

\({\text{d}}\left\lceil A \right\rceil = \frac{{ - k\left\lceil A \right\rceil ^{2} }}{{{\text{d}}t^{2} }}\)

t_1/2 = 1/k[A]₀

t_0.9 = (0.11/ k) [A]₀

Photodegradation of formamethylflavin in acidic solution

Thermolysis of formamethylflavin, hydrolysis of esters in alkaline solution