diff --git a/R/new_ode_model.R b/R/new_ode_model.R
index 567fb410..50e46fe8 100644
--- a/R/new_ode_model.R
+++ b/R/new_ode_model.R
@@ -357,9 +357,9 @@ new_ode_model <- function (model = NULL,
                        "\\[OBS_COMP\\]", obs$cmt,
                        "\\[DOSE_COMP\\]", dose$cmt,
                        "\\[OBS_SCALE\\]", obs$scale,
-                       "\\[OBS_VARIABLE\\]", deparse(obs$variable),
+                       "\\[OBS_VARIABLE\\]", paste0(deparse(obs$variable), collapse = ""),
                        "\\[DOSE_BIOAV\\]", dose$bioav,
-                       "\\[DOSE_DUPLICATE\\]", deparse(dose$duplicate),
+                       "\\[DOSE_DUPLICATE\\]", paste0(deparse(dose$duplicate), collapse = ""),
                        "\\[CODE\\]", code,
                        "\\[PK_CODE\\]", pk_code,
                        "\\[DOSE_CODE\\]", dose_code,