Cocrystals of S-naproxen (S-NPX) or RS-naproxen (RS-NPX) and 4,4′bipyridine (BiPY) were prepared by the Gaseous Anti Solvent (GAS) method using CO₂ as antisolvent. S-NPX and BiPY cocrystals were also produced by Cocrystallization with Supercritical Solvent (CSS) using CO₂ as a solvent though leading to mixtures of cocrystals and homocrystals. Hydrogen-bond networks and stoichiometries of produced cocrystals were identical whatever the mode of preparation (evaporation, grinding and CO₂-assisted processes) and matched those already described in literature: S-NPX₂:BiPY₁ and RS-NPX₂:BiPY₁. The effects of the NPX:BiPY molar ratio and of the processing conditions were investigated. By GAS, an excess of BiPY in the initial processed mixture was mandatory to produce pure S-NPX₂:BiPY₁ cocrystals whereas pure RS-NPX₂:BiPY₁ cocrystals were identically produced from mixtures of 2:2 and 2:1 NPX:BiPY initial ratio. No enrichment of the product in any of the naproxen enantiomer was reached, even when mixtures of S- + RS-NPX were coprocessed with bipyridine.

_{S-萘普生 (S-NPX) 或 RS-萘普生 (RS-NPX) 和 4,4'联吡啶 (BiPY) 的共晶是通过使用 CO 2}作为反溶剂的气态反溶剂 (GAS) 方法制备的。_{S-NPX 和 BiPY 共晶也通过使用 CO 2}作为溶剂的超临界溶剂 (CSS) 共结晶来生产，但会导致共晶和均晶的混合物。_{无论采用何种制备方式（蒸发、研磨和 CO 2}辅助工艺），所产生的共晶的氢键网络和化学计量都是相同的，并且与文献中已经描述的相匹配：S-NPX ₂ :BiPY ₁和 RS-NPX ₂ :BiPY ₁. 研究了 NPX:BiPY 摩尔比和加工条件的影响。通过 GAS，在初始处理的混合物中过量的 BiPY 必须生产纯 S-NPX ₂：BiPY ₁共晶，而纯 RS-NPX ₂：BiPY ₁共晶同样由 2：2 和 2：1 NPX 的混合物生产： BiPY 初始比率。即使在 S- + RS-NPX 的混合物与联吡啶共处理时，也没有达到任何萘普生对映体中产物的富集。