I suppose theoretically you could buy some fish oil supplements, use a syringe to suck out the oil, then use another syringe to fill the little "skins" with N. Seems like it would take ages, though, and the N-filled "skins" would be at risk of leaking while you're filling the rest. To me it seems like a lot of hassle to avoid a bad taste. Can't we think of some larger "skin" you could use - something water-resistant but not stomach-acid resistant?
Update: Having browsed the internet a little, I think I'd buy some good chocolates filled with something soft (buttercream, brandied cherries, whatever) and inject them with N. I wouldn't need 75 of them, I hope!