Metformin XR dosage and timing

Ok, so I have been diagnosed for about 4 years and on Metformin for about 2 years.

Its fair to say over the 4 years i have had periods of conscious effort in looking after my diet and longer periods of burying my head in the sand and doing what I like, however my recent retinopathy results (indication of changes that may lead to retinopathy, no treatment required yet) gave me the kick up the backside i needed and I am now back to making an effort and paying closer attention to my diet and BG levels.

So using today as an example, i was 7.4 first thing in the morning, 7.9 breakfast +2, 6.2 immediately prior to lunch and 6.9 Lunch +2. The day previous the same numbers were 8, 8.5, 6.2, 9.1. Generally my levels about 7pm (when i get in from work and before my evening meal) is around 5-6 in general.

I am currently taking 1500mg of Metformin XR just after my evening meal.

My question is this - has anyone experimented with taking Metformin XR at different times and perhaps even splitting the dose to achieve better results? the reason i ask is because it seems that if i start with a high fasting level, it continues for the rest of the day and I was hoping that staggering my dose my help to even out my levels through out the day instead of coming down gradually then spiking again with my evening meal.

Well that there is exactly why i have asked the question, i have made the dietary changes for the last three weeks taking care to minimise my carb intake (albeit not measured) and even to reduce sugar intake from natural sources where they exist whilst maintaining a balanced diet. I have yet to see any substantive changes in my BG levels over what i saw with my sporadic testing prior to the dietary changes.

I would also add that i am less concerned with the differences between normal and modified released versions of Metformin (i am on modified because of the side effects) but was unfamiliar with the mechanism of action of the drug (such as its half life) and whether a staggered approach would achieve a more consistent absorption level.

If as you say the plasma concentration over a 24 hour period is unaffected by the time it is taken and it naturally hits a saturation point/plateau then i can understand why it would have no impact on BG levels, however, as 1500mg is 500mg below the maximum recommended dose, I would have to assume that there is some "wiggle room".

I guess the real question here is whether or not my current dosage hits said saturation point and whether there are peaks and troughs in the plasma concentration levels over a 24 hour that could be smoothed out by a staggered approach.