The goal in patenting extended release formulations has to be broad enough to prevent the development of generic alternatives, and narrow enough to prevent invalidity arguments.
If the patent claim is valid and infringed then the generic extended release version cannot be made.
When courts evaluate patent infringements it is not usually of consequence how the extended release drug delivery system in either the original brand or the generic is classified.
The key point  for legal consideration appears to be both the specific drug delivery technology used by the generics manufacturer, as well as the physical characteristics and pharmacokinetic properties of the extended release product (both in vitro and in vivo).
Big pharma see extended release drugs as a logical follow-on strategy to extend a compound's patent life while generics companies see it as a interesting area in which the law seems favourable to generics in some cases.
Patients taking metoprolol succinate extended release should avoid abrupt cessation of therapy.
Metoprolol succinate extended release should be used with caution in patients who have bronchospastic disease, diabetes, thyrotoxicosis, or peripheral vascular disease; who are undergoing major surgery, or who take calcium channel blockers of the verapamil and diltiazem type.
There is a risk of worsening cardiac failure during up-titration of the dose of metoprolol succinate extended release.
Patients should be advised to (1) avoid operating automobiles and machinery or engaging in other tasks requiring alertness until the patient's response to therapy with metoprolol succinate extended release has been determined; (2) contact a physician if any difficulty in breathing occurs; (3) inform the physician or dentist before any surgery that he or she is taking metoprolol succinate extended release.
Monotherapy with Once-Daily Guanfacine Extended Release Significantly Improved ADHD Symptoms
In this study, investigators randomized 345 subjects to receive placebo or 2 mg, 3 mg or 4 mg guanfacine extended release once daily.
Compared to placebo, children aged 6 to 17 years treated with guanfacine extended release showed significant improvements in the core symptoms of ADHD (hyperactivity, impulsivity and inattention), as reflected by total scores on the primary efficacy measurement, the ADHD Rating Scale (ADHD-RS-IV).
As the first selective alpha-2A-adrenoceptor agonist being developed as an ADHD treatment, guanfacine extended release will be a welcomed addition to our armamentarium of ADHD medications.
We are pleased to have worked with Elite Pharmaceuticals to develop products which utilize the firm's extended release drug delivery technology.
This product is another example of how our proprietary extended release technology can be utilized by our partners.