[Determination of sennoside A in oriental pharmaceutical decoctions containing Rhei Rhizoma by ion-pair high-performance liquid chromatography]

A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise determination of sennoside A in oriental pharmaceutical decoctions containing Rhei Rhizoma. This method was compared with other two methods, i.e. ion-suppression and phosphate buffer methods. Sennoside A was eluted without interference in this ion-pair method, while the determination of sennoside A was interfered by co-existing components in the other two methods.

Diagnosis of the abuse of magnesium and stimulant laxatives

A reliable diagnosis of laxative abuse can only be reached by chemical analysis. We report a modified thin layer chromatography approach for the detection and confirmation of over-the-counter colonic stimulant laxatives. Potential interference by dietary and drug components chemically similar to anthraquinones was investigated and the method was found to be specific in this respect. The diagnosis of magnesium laxative abuse is more difficult since magnesium is a component of body fluids. By inducing diarrhoea with magnesium salts in volunteers we have established that the diagnosis can be made by measuring magnesium concentrations in stool water, with 30 mmol/L being an appropriate cut-off concentration.

Magnesium levels after magnesium-containing cathartics

To determine the effect on serum Mg++ levels of oral Magnesium-containing cathartics (MgCC) used in the treatment of suspected drug overdose, a prospective, non-randomized study of 24 cases of suspected drug overdose was conducted. Ten cases admitted to the observation unit were assigned to the single dose MgCC group. Fourteen cases admitted to either the ICU or the observation unit were assigned to the multiple dose MgCC group. Single dose cases received 30 gm of magnesium sulfate (MgSO4) at 0 hours. Multiple dose cases received 3 30 gm doses of MgSO4 at 0, 4, and 8 hours. Mg++ levels were measured prior to each MgSO4 dose and 1 and 4 hours after the final dose in both groups. In the single dose group, there was no difference between baseline Mg++ levels and post MgSO4 levels, and only 2/10 developed slightly elevated levels (2.2, 2.3 mEq/L). In the multiple dose group, levels increased and remained significantly higher than baseline after the second MgSO4 dose, and 9/14 developed elevated levels (2.2 to 5.0 mEq/L). All patients who developed elevated Mg++ levels had normal BUN and creatinine values. When the single and multiple dose groups were compared, baseline Mg++ levels were no different (1.68 +/- 0.21 vs 1.69 +/- 0.24, p = 0.952), but peak Mg++ levels were significantly higher in the multiple dose group (1.80 +/- 0.31 vs 2.61 +/- 0.86, p = 0.004). Cases that developed hypermagnesemia had slightly higher baseline Mg++ levels (1.78 +/- 0.22 vs 1.60 +/- 0.19 mEq/L, p = 0.041). In the multiple dose group, higher peak Mg++ levels were noted in cases involving ingestions of anticholinergic or opioid drugs (2.83 vs 1.98, p = 0.025). Hypermagnesemia developed in some cases with normal renal function, blood pressure, and urine output. We conclude that significant hypermagnesemia can occur rapidly after use of multiple dose Mg++ cathartics in standard doses in patients with normal renal function.

Factitious diarrhoea

Gastroenterologists often have to deal with patients with chronic diarrhoea. The vast majority will suffer from functional bowel syndrome. A few will present with a clear-cut organic disease. If chronic diarrhoea remains unexplained after extensive testing, if daily stool volume is high (greater than 500 g/24 h) and if the patient is female, factitious diarrhoea should be considered. Melanosis coli on sigmoidoscopy, cathartic colon on barium enema examination, a positive room search and chemical detection of the presence of specific laxatives in urine or stool may lead to the correct diagnosis. Treatment and management of such patients is difficult. Denial is the usual response to confrontation. Counselling and guidance by psychiatrists or psychologists is often not accepted by the patient. In many cases the role of the physician may be limited to preventing further potentially dangerous diagnostic and therapeutic interventions.

Bulk laxatives: their dietary fibre composition, degradation, and faecal bulking capacity in the rat

The intestinal dietary fibre degradation and faecal bulking capacity of various bulk laxatives were investigated by means of balance experiments on rats. Nitrogen, fat, and mineral excretion in faeces was also studied. The dietary fibre content of the various bulk laxatives was quite different (in g/kg dry matter): ACO fibre tablets (barley and citrus pulp), 451; Fiberform (wheat bran-based), 817; Inolaxol (sterkulia gum), 696; and Vi-Siblin (ispaghula husk), 533. The increase in faecal dry matter per 1 g dietary fibre was similar with ACO fibre tablets, Fiberform, and Vi-Siblin. Inolaxol gave a significantly (p less than 0.001) higher faecal dry-weight increment, mainly due to an increased mineral excretion. Of the dry-weight increment, 59-82% constituted undegraded dietary fibre. Thus, 68-97% of the fibre passed through the gastrointestinal tract without being degraded. All the bulk laxatives caused a similar increase in the faecal N content, whereas the increase in faecal lipids was most pronounced with Vi-Siblin. The water-holding capacity of faeces was more pronounced with Inolaxol and Vi-Siblin than with ACO fibre tablets and Fiberform.

A screening method for establishing laxative abuse

Abuse of laxatives, most of them belonging to the group of colonic stimulants or cathartics, can cause various disorders. Extensive diagnostic work can be avoided by early toxicological screening of the suspected patients with respect to laxatives. Because no screening method of this kind was available, we developed a procedure with which all phenolic and anthraquinone laxatives--except sodium picosulfate--can be detected in urine. This method is based on high-performance thin-layer chromatography in two systems after pretreatment of a 20-mL urine sample with beta-glucuronidase and subsequent column extraction. The procedure is very sensitive: at least 32 h after a single dose of bisacodyl, danthron, phenolphthalein, or sennoside, the drug can be detected in the urine. Bisoxatin and oxyphenisatin are still detectable in the urine 18 h after intake. The method is also highly specific; none of 73 other drugs interfered in either of the two chromatographic systems. This procedure can be helpful for the early diagnosis of laxative abuse.