the invention relates to the use of purine derivatives for the production of medicaments for the treatment of mucoviscidosis and diseases related to protein addressing errors in cells , said derivatives being of formula : where r2 , r6 and r9 , independently = halogen , a r — nh —, r — nh — nh —, nh 2 — r ′— nh or r — nh — r ′— nh — group , where r = straight or branched chain saturated or unsaturated alkyl , aryl , cycloalkyl , or heterocyclyl group , r ′= straight or branched chain , saturated or unsaturated alkylene , arylene or cycloalkylene , r and r ′ each include 1 to 8 carbon atoms optionally substituted with one or more — oh , halogen , amino or alkyl groups , r2 furthermore may be a heterocycle optionally with a straight or branched chain saturated or unsaturated alkyl , aryl or cycloaryl or a heterocycle optionally substituted by one or more — oh , halogen , amino or alkyl groups , r9 furthermore may be a straight or branched chain saturated or unsaturated alkyl , aryl or cycloalkyl and r2 and r9 furthermore may be hydrogen with the exception of 2 -- 6 - benzylamino - 9 - methylpurine .