Effect of filtration on morphine and particle content of injections prepared from slow-release oral morphine tablets

Table 1 Recovery of morphine after cold extraction and filtration

Filtration	Volume of extract (ml)	Amount of morphine (mg)	P versus cig. filter alone*
None	3.0	55.8 ± 1.9 (N = 4)
Cigarette filter
First filtrate	1.7 ± 0.1	31.7 ± 2.3
First rinse	1.1 ± 0.0	12.8 ± 0.7
Second rinse	1.1 ± 0.1	5.9 ± 0.2
Total	3.9 ± 0.1	50.5 ± 1.8
Cotton wool
First filtrate	1.7 ± 0.1	30.5 ± 1.9
First rinse	1.1 ± 0.1	10.6 ± 1.2
Second rinse	1.0 ± 0.0	5.0 ± 0.8
Total	3.8 ± 0.0	46.1 ± 0.1	0.099
0.45 μm filter	1.9 ± 0.0	33.9 ± 1.0	0.098^†
Combined filtration
Cig.+ 0.45 μm filter	5.0 ± 0.2	51.5 ± 0.7	0.701
Cig. + 0.22 μm filter	4.9 ± 0.2	51.9 ± 1.4	0.410

Data are mean ± SD, N = 3 except where otherwise indicated.
*This figure provides a comparison of the amount of morphine recovered through use of the target filter to that recovered through use of a cigarette filter. Comparisons were made by Mann-Whitney U test (a non-parametric analogue of the t-test), 2-tailed. Results are consistent with parametric analysis with Games-Howell post-hoc tests with the exception of ^†0.45 μm filters (p < 0.05). P values greater than 0.05 suggest that it is unlikely that there is any real difference between the amount of morphine recovered in the two compared techniques.

ISSN: 1477-7517