Prodrugs in medicinal chemical structures are rarely discussed, so this article explores the obviousness of prodrug chemical structures through the case of Amerigen Pharmaceuticals Limited v. UCB Pharma GmBH. (Fed. Cir. 2019).Amerigen filed a third-party review (IPR) with the USPTO's Patent Trial and Petition Board (PTAB) challenging U.C.B's US Patent No. 6,858,650 (' 650 patent).Amerigen Pharmaceuticals pointed out that the application scope of the '650 patent is obvious and unpatentable, but the PTAB believes that the '650 patent is patentable, and Amerigen Pharmaceuticals disagrees with this decision. So file an appeal.1. Compounds of general formula I (Fig. 1.) in which R denotes C1 -C6 -alkyl, C3 -C10 -cycloalkyl, substituted or unsubstituted phenyl and X- is the acid residue of a physiologically compatible inorganic or organic acid.2. Compounds in accordance with claim 1, characterised in that X- in each case is an acid ester of hydrochloric acid, hydrobromic acid, phosphoric acid, sulphuric acid, nitric acid, acetic acid, propionic acid, palmitic acid, stearic acid, maleic acid, fumaric acid, oxalic acid, succinic acid, DL-malic acid, L-(-)-malic acid, D-(+)-malic acid, DL-tartaric acid, L-(+)-tartaric acid, D- (-)-tartaric acid, citric acid, L-aspartic acid, L-(+)-ascorbic acid, D-(+)-glucuronic acid, 2-oxopropionic acid (pyruvic acid), furan-2-carboxylic acid (mucic acid acid), benzoic acid, 4-hydroxybenzoic acid, salicyclic acid, vanillic acid, 4-hydroxycinammic acid, gallic acid, hippuric acid (N-benzoyl-glycine), aceturic acid (N-aectylglycine), phloretinic acid (3-(4 -hydroxyphenyl)-propionic acid), phthalic acid, methanesulfonic acid or orotic acid.3. Compounds in accordance with claims 1, characterised in that they have general formula 2(Fig. 2.) in which R denotes C1 -C6 -alkyl, C3 -C10 -cycloalkyl, substituted or unsubstituted phenyl and X- is the acid residue of a physiologically compatible inorganic or organic acid.4. Compounds in accordance with claim 3, characterised in that X in each case is an acid ester of hydrochloric acid, hydrobromic acid, phosphoric acid, sulphuric acid, nitric acid, acetic acid, propionic acid, palmitic acid, stearic acid, maleic acid , fumaric acid, oxalic acid, succinic acid, DL-malic acid, L-(-)-malic acid, D-(+)-malic acid, DL-tartaric acid, L-(+)-tartaric acid, D-( -)-tartaric acid, citric acid, L-aspartic acid, L-(+)-ascorbic acid, D-(+)-glucuronic acid, 2-oxopropionic acid (pyruvic acid), furan-2-carboxylic acid (mucic acid ), benzoic acid, 4-hydroxybenzoic acid, salicyclic acid, vanillic acid, 4-hydroxycinammic acid, gallic acid, hippuric acid (N-benzoyl-glycine), aceturic acid (N-aectylglycine), phloretinic acid (3-(4- hydroxyphenyl)-propionic acid), phthalic acid, methanesulfonic acid or orotic acid.5. Compounds in accordance with claims 3, characterised in that they are R-(+)-2-(3-(diisopropylamino-1-phenylpropyl)-4-hydroxymethyl -phenylisobutyrate ester hydrogen fumarate, R-(+)-2- (3-(diisopropylamino-1-phenylpropyl)-4-hydroxymethylphenylisobutyr ate ester-hydrochloride hydrate.21. A method of treating a patient suffering from urinary incontinence, which method comprises the step of administering to said patient an effective amount of a compound according to claim 1.22. A method of treating a patient suffering from urinary incontinence, which method comprises the step of administering to said patient an effective amount of a compound according to claim 3.23. A method of treating a patient suffering from urinary incontinence, which method comprises the step of administering to said patient an effective amount of a compound according to claim 5.24. The method of any one of claims 21-23, wherein the urinary incontinence disorder is urge incontinence.R in Figure 1 represents alkyl substituent with carbon number of 1-6, cycloalkyl substituent of C3-C10, substituted or unsubstituted phenyl substituent, and X- refers to the residue of organic acid or inorganic acid .R in Figure 2 represents alkyl substituent with carbon number of 1-6, cycloalkyl substituent with C3-C10, substituted or unsubstituted phenyl substituent, and X- refers to the residue of organic acid or inorganic acid .The main chemical structure of this case, Fesoterodine (Fig. 3), can be covered in either the 1st to 5th or 21st to 24th patent application scope.Fesoterodine is a cholinergic antagonist (antimuscarinic drug), which is medically a drug for the treatment of urinary incontinence. The related product is Toviaz®, which was approved by the Food and Drug Administration (FDA) in the United States in 2008.Fesoterodine (Fig. 3) is circled in two places, circle 2 represents the 2nd position, which has isobutyryl ester at the 2nd position, and circle 5 represents the 5th position, which has a hydroxymethyl group.Fesoterodine is a prodrug. Unlike typical drugs, a prodrug is an inactive molecule that needs to be transformed into an active therapeutic form in the human body.Because Vietnam has joined or signed CPTPP, EVFTA, RCEP, the National Assembly of the country passed the 2022 Intellectual Property Law Amendment Act (2022 IP Law) on June 16, 2022, which affects many aspects such as patents, trademarks, copyrights, etc., with some exceptions , the amendments are scheduled to take effect on January 1, 2023.This article excerpts some important changes in the relevant regulations on invention and design patents.