diff --git a/env.yaml b/env.yaml
index 1839345..35738d5 100644
--- a/env.yaml
+++ b/env.yaml
@@ -25,6 +25,7 @@ dependencies:
   - isort
   - nglview>=3.0.6,<3.1.0
   - openff-interchange >= 0.4.0
+  - openff-packmol = 0.1
   - openff-nagl-base >= 0.5.2
   - openff-nagl-models
   - openff-forcefields >= 2025.10.1
diff --git a/ptm_sim.ipynb b/ptm_sim.ipynb
index 899e3d6..7474142 100644
--- a/ptm_sim.ipynb
+++ b/ptm_sim.ipynb
@@ -872,7 +872,7 @@
    },
    "outputs": [],
    "source": [
-    "from openff.interchange.components._packmol import (\n",
+    "from openff.packmol import (\n",
     "    RHOMBIC_DODECAHEDRON,\n",
     "    solvate_topology,\n",
     ")\n",