Table 2.

Solubility product (K_sp), intrinsic solubility (S_0,CC), and solubility advantage ( $\mathit{\text{SA}}=\frac{S_{0,\mathit{\text{CC}}}\mathit{\text{ or }}{S}_{0,\mathit{\text{Salt}}}}{S_{0,\mathit{\text{LTG}}}}$) of LTG cocrystals and salts.

Solid Phase	Ksp (M2)	S0,CC or S0,Salt (M)	SA
LTG-NCT Cocrystal	(1.4±0.4) ×10−4	1.2 × 10−2	18
LTG-HCl Salt	(6.7±0.53) × 10−5 a	8.2 × 10−3	12
LTG-SAC Salt	(1.1±0.2) × 10−5	3.3 × 10−3	5
LTG-MP Cocrystal	(5.3±0.47) × 10−7 b	7.3 × 10−4	1.1
LTG-PB Cocrystal	(1.2±0.5) × 10−8	1.1 × 10−4	0.2

^aK_sp of LTG-HCl was calculated from reported solubility of 0.46 mg/mL at 37°C (pH 1.2) from reference²⁷. K_sp of the salt was estimated at 25°C from [LTGH⁺] and [Cl⁻] concentrations calculated from the dissolved salt and HCl concentrations, using a heat of solution value of 30 kJ/mol.

^bSteady state concentration from dissolution data in reference (3) was used to calculate the K_sp of lamotrigine-methylparaben (LTG-MP) cocrystal, where cocrystal was reported to be stable.