On a class of realizable propositional formulas

Propositional formula is called regularly realizable if there exists a number realizing (in Kleene's sense) every closed, arithmetical substitution instance of the formula. In this paper there is constructed a class $R$ of propositional formulas with the following properties: I) $R$ contains all intuitionistically derivable propositional formulas and is closed relative to rules of intuitionistic propositional calculus; 2) $R$ is recursively decidable; 3) every formula of $R$ is regularly realizable.
All realizable propositional formulas known to the author are contained in $R$.