The n-octyl β-d-glucoside/water binary phase diagram (temperature vs concentration) and the aggregation parameters of the individual phases have been determined. n-Octyl β-d-glucoside forms four different phases together with water. At temperatures below 22 °C, there is an isotropic solution region from neat water extending up to almost 60 wt % n-octyl β-d-glucoside. As the concentration is further increased, three liquid crystalline phases form in the following order:  hexagonal, cubic, and lamellar. At high surfactant concentrations (>93 wt %) the lamellar phase is in equilibrium with hydrated crystals. The hexagonal phase disappears at temperatures slightly higher than 20 °C. The solution region has been investigated with 1H-NMR to deduce the self-diffusion coefficients of both n-octyl β-d-glucoside and water. From these results it has been possible to draw conclusions about the surfactant aggregation behavior at dilute concentrations and when the n-octyl β-d-glucoside concentration is increased. The water diffusion in the n-octyl β-d-glucoside/water system has been compared with the diffusion process of water in a glucose solution, and it has been possible to interpret the data in terms of water diffusion in a glucose solution with some additional obstruction effects from the micellar hydrocarbon cores. The liquid crystalline phases have been examined by means of small-angle X-ray scattering and analyzed in terms of repetition distances and area/head group in the hexagonal, cubic, and lamellar phases. An important result of this study is the fact that the area per glucose unit in the surfactant is an almost invariant quantity across the phase diagram.

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The temperature versus concentration phase diagrams of the n-nonyl β-glucoside/water and the n-decyl β-glucoside/water systems are presented. The micellar region of the n-nonyl β-glucoside has been studied using 1H NMR self-diffusion to obtain information about the micellar size. Nonspherical aggregates are formed at concentrations immediately above the cmc. Three different liquid crystalline phases are formed as the concentration of n-nonyl β-glucoside is increased, viz. a hexagonal, a bicontinuous cubic (of space group Ia3d), and a lamellar phase. 1H NMR self-diffusion measurements have also been performed across the phase boundary separating the micellar and the cubic regions. It was found that there is no discontinuity in the surfactant self-diffusion when crossing this phase boundary. A particular feature of the n-decyl β-glucoside is the occurrence of a phase separation into two liquid isotropic solutions in the (total) surfactant concentration interval from approximately 0.1 to 17 wt % surfactant. The dilute and concentrated solutions have been examined by means of time-resolved fluorescence quenching (TRFQ). It was found that, at the lower phase boundary, nonspherical discrete aggregates are formed, whereas at the upper phase boundary (17 wt %), the aggregates are large. At high surfactant concentration (>65 wt %), a lamellar liquid crystalline phase is formed. The liquid crystalline phases present in the two binary phase diagrams have been characterized by small-angle X-ray scattering (SAXS). The results have been analyzed in terms of repetition distances and surfactant head-group areas. An important result from the SAXS analysis is that the head-group area is an almost invariant parameter in the different liquid crystalline phases.

That 3alpha-hydroxy-5alpha/beta-pregnane steroids (GABA steroids) have modulatory effects on the GABA-A receptor is well known. In behavioral studies in animals high exogenous dosages give concentrations not usually reached in the brain under physiological conditions. Animal and human studies show that GABA-A receptor-positive modulators like barbiturates, benzodiazepines, alcohol, and allopregnanolone have a bimodal effect. In pharmacological concentrations they are CNS depressants, anesthetic, antiepileptic, and anxiolytic. In low dosages and concentrations, reached endogenously, they can induce adverse emotional reactions in up to 20% of individuals. GABA steroids can also induce tolerance to themselves and similar substances, and rebound occurs at withdrawal. Menstrual cycle-linked disorders can be understood by the concept that they are caused by the action of endogenously produced GABA-steroids through three mechanisms: (a) direct action, (b) tolerance induction, and (c) withdrawal effect. Examples of symptoms and disorders caused by the direct action of GABA steroids are sedation, memory and learning disturbance, clumsiness, increased appetite, worsening of petit mal epilepsy, negative mood as tension, irritability and depression during hormone treatments, and the premenstrual dysphoric disorder (PMDD). A continuous exposure to GABA steroids causes tolerance, and women with PMDD are less sensitive to GABA-A modulators. A malfunctioning GABA-A receptor system is related to stress sensitivity, concentration difficulties, loss of impulse control, irritability, anxiety, and depression. An example of withdrawal effect is "catamenial epilepsy," when seizures increase during menstruation after the withdrawal of GABA steroids. Similar phenomena occur at stress since the adrenals produce GABA steroids during stress.

Premenstrual syndrome (PMS) is a menstrual cycle-linked condition with both mental and physical symptoms. Most women of fertile age experience cyclical changes but consider them normal and not requiring treatment. Up to 30% of women feel a need for treatment. The aetiology is still unclear, but sex steroids produced by the corpus luteum of the ovary are thought to be symptom provoking, as the cyclicity disappears in anovulatory cycles when a corpus luteum is not formed. Progestogens and progesterone together with estrogen are able to induce similar symptoms as seen in PMS. Symptom severity is sensitive to the dosage of estrogen. The response systems within the brain known to be involved in PMS symptoms are the serotonin and GABA systems. Progesterone metabolites, especially allopregnanolone, are neuroactive, acting via the GABA system in the brain. Allopregnanolone has similar effects as benzodiazepines, barbiturates and alcohol; all these substances are known to induce adverse mood effects at low dosages in humans and animals. SSRIs and substances inhibiting ovulation, such as gonadotrophin-releasing hormone (GnRH) agonists, have proven to be effective treatments. To avoid adverse effects when high dosages of GnRH agonists are used, add-back hormone replacement therapy is recommended. Spironolactone also has a beneficial effect, although not as much as SSRIs and GnRH agonists.

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