Clarithromycin form patent- Canada case

Abbots Canadian Patent No. 2,386,527, has a claim 5 on a crystalline clarithromycin ( Form I) useful in treating bacterial infections.
The ’527 patent discloses that clarithromycin can exist in at least two crystalline forms, which Abbott has named Form I and Form II. There was also evidence before the applications judge that clarithromycin can exist in a third crystal form, known as Form 0. The patent specification describes Form I as having “an intrinsic rate of dissolution about three times that of Form II crystals”, which is asserted to “increas[e] bioavailability of the antibiotic and provid[e] significant formulation advantages” (at page 2 of the ’527 patent). In the only claim of issue , claim 5, the inventors claim:
The use of 6-O-methylerythromycin A Form I according to claim 1 or 2 in the treatment of bacterial infections in a host mammal.

Sandoz argued that prior art ’602 patent anticipated ‘527 patent. ‘602 begins by stating at the beginning of column I what the parties acknowledge was already previously known, that is that clarithromycin (6-O-methylerythromycin A) was already known as was its use as an antibacterial agent and that there were several known methods for preparing it. Experts for both Abbott and Sandoz agree that at least some of the crystalline forms produced using the ’602 as well as other prior art references would be Form I. Abbott’s experts Byrn and Atwood opine that under the probable drying conditions used, a mixture of Form 0 and Form I crystals would result. The fact that it is not entirely Form I does not matter since the parties have agreed that a proper construction of claim 5 contemplates a mixture of crystalline forms of clarithromycin which includes Form I. Sandoz’s experts were more certain that Form I would be the resultant crystal (Rohani Affidavit paragraph 604, Lee-Ruff Affidavit paragraphs 136 to 138, Eckhardt Affidavit paragraphs 195 and 196). It does not matter whether the crystals were entirely Form I or a mixture of Form I and something else, the agreed upon construction of claim 5 has been met.

Hence claim 5 was construed as “5. The use of clarithromycin, at least some of which is Form I, for the treatment of bacterial infections in a host mammal”.
Hence claim 5 was found to be invalid