Textual Amendments
F1Sch. 9A inserted (31.12.2020) by The Human Medicines (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/775), reg. 1, Sch. 4 (as amended by S.I. 2020/1488, reg. 1, Sch. 2 para. 191); 2020 c. 1, Sch. 5 para. 1(1)
5.—(1) This paragraph applies for the purposes of the definition of “similar active substance” in relation to chemical medicinal products.U.K.
(2) The principal molecular structural features are the relevant structural components of an active substance, which may be the whole or part of the molecule.
(3) Whether the principal molecular structural features are the same between two or more molecules will be identified by comparison of their structures.
(4) Isomers, mixtures of isomers, complexes, esters, ethers, salts and derivatives of the original active substance, or an active substance that differs from the original active substance only with respect to minor changes in the molecular structure, such as a structural analogue, are to be considered similar.
(5) Synthetic polynucleotide substances, single or double stranded, consisting of two or more distinct nucleotides where—
(a)the difference in the nucleotide sequence of the purine and pyrimidine bases or their derivatives is not major, are to be considered similar, therefore for antisense or interfering nucleotide substances, addition, substitution or deletion of a nucleotide not significantly affecting the kinetics of hybridisation to the target are usually to be considered similar; and
(b)the difference in structure related to modifications of the ribose or deoxyribose backbone sugars or to the replacement of the backbone sugars by synthetic analogues usually result in substances being considered similar, and for antisense or interfering nucleotide substances, changes in the ribose or deoxyribose backbone sugars not significantly affecting the kinetics of hybridisation to the target are usually to be considered similar.]