Study on the formulation of o/w emulsion as carriers for lipophilic drugs

Enhancing topical delivery of ISRIB: Optimizing cream formulations with chemical enhancers and pH adjustment

Chemical warfare agents, particularly vesicants like lewisite, pose a threat due to their ability to cause skin damage through accidental exposure or deliberate attacks. Lewisite rapidly penetrates the skin, causing inflammation and blistering. This study focuses on developing a cream formulation of a therapeutic agent, called integrated stress response inhibitor (ISRIB), to treat lewisite-induced injuries. Moreover, animal studies demonstrate a molecular target engagement (ISR) and significant efficacy of ISRIB against lewisite-induced cutaneous injury. The goal of this formulation is to enhance the delivery of ISRIB directly to affected skin areas using an oil-in-water cream emulsion system. We investigated various excipients, including oils, surfactants, emollients, and permeation enhancers, to optimize ISRIB's solubility and penetration through the skin. The result of this study indicated that the optimal formulation includes 30 % w/w of N-Methyl-2-pyrrolidone, dimethyl sulfoxide and Azone® at a pH of 5. 5. It delivered the highest amount of ISRIB into the skin, demonstrating highest skin absorption with no detectable systemic exposure. Additionally, characterization of the cream, including texture analysis, emulsion type, and content uniformity, confirmed its' suitability for topical application. These findings suggest that ISRIB cream formulation is a promising approach for the localized treatment of skin injuries caused by lewisite.

Intranasal haloperidol-loaded miniemulsions for brain targeting: Evaluation of locomotor suppression and in-vivo biodistribution

Haloperidol is a commonly prescribed antipsychotic drug currently administered as oral and injectable preparations. This study aimed to prepare haloperidol intranasal miniemulsion helpful for psychiatric emergencies and exhibiting lower systemic exposure and side effects associated with non-target site delivery. Haloperidol miniemulsions were successfully prepared by spontaneous emulsification adopting 2(3) factorial design. The effect of three independent variables at two levels each namely; oil type (Capmul®-Capryol™90), lipophilic emulsifier type (Span 20-Span 80) and HLB value (12-14) on globule size, PDI and percent locomotor activity inhibition in mice was evaluated. The optimized formula (F4, Capmul®, Tween 80/Span 20, HLB 14) showed globule size of 209.5±0.98nm, PDI of 0.402±0.03 and locomotor inhibition of 83.89±9.15% with desirability of 0.907. Biodistribution study following intranasal and intravenous administration of the radiolabeled (99m)Tc mucoadhesive F4 revealed that intranasal administration achieved 1.72-fold higher and 6 times faster peak brain levels compared with intravenous administration. Drug targeting efficiency percent and brain/blood exposure ratios remained above 100% and 1 respectively after intranasal instillation compared to a maximum brain/blood exposure ratio of 0.8 post intravenous route. Results suggested the CNS delivery of major fraction of haloperidol via direct transnasal to brain pathway that can be a promising alternative to oral and parenteral routes in chronic and acute situations. Haloperidol concentration of 275.6ng/g brain 8h post intranasal instillation, higher than therapeutic concentration range of haloperidol (0.8 to 5.15ng/ml), suggests possible sustained delivery of the drug through nasal route.

Permeation studies and histological examination of sheep nasal mucosa following administration of different nasal formulations with or without absorption enhancers

This study was designed to investigate the possible histological effects of different intranasal (IN) formulations of indomethacin (IND) on nasal mucosa in sheep. For this purpose, oil-in-water (O/W) emulsion (E) and solution (S) formulations including 3 mg/mL of IND were prepared. Penetration enhancers such as polyvinylpyrolidone (PVP), citric acid (CA) and sodium taurocholate (NaT) were added to emulsion (1%) at the final step into the formulations. First, the effect of penetration enhancers on permeation of IND was evaluated by in vitro permeation studies in which sheep nasal mucosa was used. According to the permeation studies PVP showed the highest enhancing effect on the permeation rate of IND from sheep nasal mucosa. Furthermore, the IND permeation from E containing PVP (1.624 +/- 0.045 mg) was significantly higher than that obtained from E (0.234 +/- 0.012 mg) (p < 0.05). For the histological studies, white Karaman sheep of approximately 20 +/- 5 kg, aged 4 to 8 months were used. They were randomly divided into eight groups, each including three sheep. Five experimental groups received different formulations of IND emulsion without/ with penetration enhancers (E-PVP, E-CA, E-NaT, E) and IND solution (S), respectively. Parallel controls were composed of either untreated groups and were given blank emulsion or isotonic sodium chloride solution (0.31 mg/kg). 2 mL of each experimental formulation was applied to both nostrils of sheep, and 1/3 central and lower regions of the nose were dissected and prepared for light microscopy. Specimens stained with hematoxylin and eosin and Gomori's trichrome were examined by light microscopy. No signs of inflammation or erosion were noticed in the nasal mucosa of the control groups. Widened epithelial intercellular spaces were noticed in E-CA, E-NaT, and E-PVP groups as well with the E-PVP group showing the largest intraepithelial separations. E-CA and E-NaT groups showed significant decrease in the amount of goblet cells, while hypoplasia was considerably moderate in the E-PVP group. Finally, intranasal administration of IND emulsion with PVP may be considered as an alternative to intravenous and per oral administrations of IND to overcome their adverse effects.

Permeation studies of indomethacin from different emulsions for nasal delivery and their possible anti-inflammatory effects

The purpose of this research was to develop an emulsion formulation of indomethacin (IND) suitable for nasal delivery. IND was incorporated into the oil phases of oil in water (O/W) and water in oil (W/O) emulsions. For this purpose, different emulsifying agents (Tween 80, Span 80 and Brij 58) were used in two emulsion formulations. When the effects of several synthetic membranes (nylon, cellulose, cellulose nitrate) were compared with the sheep nasal mucosa, the cellulose membrane and sheep nasal mucosa showed similar permeation properties for O/W emulsion (P > 0.05). To examine the absorption characteristics of IND, the anti-inflammatory properties of intravenous solution of IND, intranasal O/W emulsions of IND (with or without enhancers) and intranasal solution of IND (IND-Sol) were investigated in rats with carrageenan-induced paw edema. When citric acid was added to the nasal emulsion, the anti-inflammatory activity was similar to that of intravenous solution (P > 0.05). Finally, it was concluded that, intranasal administration of IND emulsion with citric acid may be considered as an alternative to intravenous and per oral administrations of IND to overcome their adverse effects.

Emulsions of oil from Adenanthera pavonina L. seeds and their protective effect

In our previous study, we developed very stable formulations of submicron oil-in-water emulsions from Adenanthera pavonina L. (family Leguminosae, subfamily Mimosoideae) seed oil, stabilised with soybean lecithin (SPC). Continuing our research, we introduced an additional co-emulsifier, Tween 80, to those formulations in order to decrease the size of the emulsion particles and improve their stability. Formulations with a mean particle size ranging from 43.6 to 306.5 nm and a negative surface charge from -45.3 to -28.5 mV were obtained. Our stability experiments also revealed that most of the tested formulations had a very good degree of stability over a 3-month storage period, both at 4 degrees C and at room temperature. Since many intravenous injectable drugs exhibit lytic activity against erythrocytes, we examined this activity for the emulsion form of cardol, a natural compound with already proven hemolytic properties. The incorporation of this agent into the emulsion caused an evident decrease in hemolytic activity (97-99%). This highly protective effect, observed against sheep erythrocytes, was independent of both the composition and the particle size of the emulsions used. Our studies suggest that nonionic surfactant/phospholipid-based emulsions containing this edible oil of A. pavonina L. may be useful as an alternative formulation matrix for pharmaceutical, nutritional or cosmetic applications of otherwise membrane-acting components.