diff --git a/lib/apiculture/openapi_documentation.rb b/lib/apiculture/openapi_documentation.rb
index 7a6641a..b86f098 100644
--- a/lib/apiculture/openapi_documentation.rb
+++ b/lib/apiculture/openapi_documentation.rb
@@ -83,7 +83,7 @@ def name
       @path.route_parameters.each do |parameter|
         # This is a bit confusing but naming is a little different between
         # apiculture and openapi
-        full_path.gsub!(":#{parameter.name}", "\{#{parameter.name}\}")
+        full_path = full_path.gsub(":#{parameter.name}", "\{#{parameter.name}\}")
       end
       Util.clean_path("#{@prefix}#{full_path}")
     end
diff --git a/spec/apiculture/openapi_documentation_spec.rb b/spec/apiculture/openapi_documentation_spec.rb
index be362de..d740a45 100644
--- a/spec/apiculture/openapi_documentation_spec.rb
+++ b/spec/apiculture/openapi_documentation_spec.rb
@@ -40,6 +40,11 @@ class PancakeApi < Apiculture::App
       route_param :topping_id, 'Pancake topping ID', Integer, cast: :to_i
       api_method :get, '/pancake/with/:topping_id' do |topping_id|
       end
+
+      desc 'Pancake api method definition has frozen strings'.freeze
+      route_param :topping_id, 'Pancake topping ID'.freeze, Integer, cast: :to_i
+      api_method :get, '/pancake/frozen/:topping_id'.freeze do |topping_id|
+      end
     end
   end
 
@@ -80,7 +85,7 @@ class PancakeApi < Apiculture::App
       end
 
       it 'will have 4 paths' do
-        expect(paths.size).to eq(3)
+        expect(paths.size).to eq(4)
       end
 
       context 'POST /pancakes' do