Effect of surfactants on absorption through membranes III: effects of dioctyl sodium sulfosuccinate and poloxalene on absorption of a poorly absorbable drug, phenolsulfonphthalein, in rats

Rutin-Loaded Transethosomal Gel for Topical Application: A Comprehensive Analysis of Skin Permeation and Antimicrobial Efficacy

This study conducts a systematic investigation of the creation and optimization of a rutin-loaded transethosome intended for topical use. The formulation's characteristics were thoroughly assessed for vesicle size (160.45 ± 1.98 nm), polydispersity index (0.235 ± 0.067), and zeta potential (-22.89 mV), with an entrapment efficiency and drug loading of 89.99 ± 1.55% and 8.9 ± 2.11%, respectively, and found to have a spherical shape by the use of transmission electron microscopy. The conversion to a gel suitable for application on the skin was carried out. The drug release form Opt-RUT-TE formulation (73.61 ± 2.55%) was significantly higher than that of release form RUT-suspension (34.52 ± 1.19%). The drug that permeated the skin from Opt-RUT-TEG (935.25 ± 10.49 μg/cm2) was significantly higher than the permeability from RUT-Suspension gel (522.57 ± 6.79 μg/cm2). Notably, tape stripping analysis revealed that the Opt-RUT-TE gel effectively penetrated the skin layers, with a higher concentration observed in the epidermis-dermis than in the RUT-suspension gel. The transethosomal gel exhibited favorable characteristics, highlighting its capacity to efficiently permeate the skin and suppress the growth of microorganisms, and Opt-RUT-TEG showed a higher microorganism inhibition zone (Gram-positive bacteria) than that of RUT-suspension gel. The investigation highlights the significant therapeutic possibilities of rutin in a transethosomal gel formulation for treating dermatological diseases by improving skin permeability and exhibiting antibacterial effects.

Assessing and mitigating pH-mediated DDI risks in drug development - formulation approaches and clinical considerations

pH-mediated drug-drug interactions (DDI) is a prevalent DDI in drug development, especially for weak base compounds with highly pH-dependent solubility. FDA has released a guidance on the evaluation of pH-mediated DDI assessments using in vitro testing and clinical studies. Currently, there is no common practice of ways of testing across the academia and industry. The development of biopredictive method and physiologically-based biopharmaceutics modeling (PBBM) approaches to assess acid-reducing agent (ARA)-DDI have been proven with accurate prediction and could decrease drug development burden, inform clinical design and potentially waive clinical studies. Formulation strategies and careful clinical design could help mitigate the pH-mediated DDI to avoid more clinical studies and label restrictions, ultimately benefiting the patient. In this review paper, a detailed introduction on biorelevant dissolution testing, preclinical and clinical study requirement and PBPK modeling approaches to assess ARA-DDI are described. An improved decision tree for pH-mediated DDI is proposed. Potential mitigations including clinical or formulation strategies are discussed.

Elucidating the insecticidal mechanisms of zein nanoparticles on Anticarsia gemmatalis (Lepidoptera: Erebidae)

Previous research suggested that positively charged zein nanoparticles [(+)ZNP] were toxic to neonates of Anticarsia gemmatalis Hübner and deleterious to noctuid pests. However, specific modes of action for ZNP have not been elucidated. Diet overlay bioassays attempted to rule out the hypothesis that A. gemmatalis mortality was caused by surface charges from component surfactants. Overlay bioassays indicated that negatively charged zein nanoparticles [(-)ZNP] and its anionic surfactant, sodium dodecyl sulfate (SDS), exhibited no toxic effects when compared to the untreated check. Nonionic zein nanoparticles [(N)ZNP] appeared to increase mortality compared to the untreated check, though larval weights were unaffected. Overlay results for (+)ZNP and its cationic surfactant, didodecyldimethylammonium bromide (DDAB), were found to be consistent with former research indicating high mortalities, and thus, dosage response curves were conducted. Concentration response tests found the LC50 for DDAB on A. gemmatalis neonates was 208.82 a.i./ml. To rule out possible antifeedant capabilities, dual choice assays were conducted. Results indicated that neither DDAB nor (+)ZNP were antifeedants, while SDS reduced feeding when compared to other treatment solutions. Oxidative stress was tested as a possible mode of action, with antioxidant levels used as a proxy for reactive oxygen species (ROS) in A. gemmatalis neonates, which were fed diet treated with different concentrations of (+)ZNP and DDAB. Results indicated that both (+)ZNP and DDAB decreased antioxidant levels compared to the untreated check, suggesting that both (+)ZNP and DDAB may inhibit antioxidant levels. This paper adds to the literature on potential modes of action by biopolymeric nanoparticles.

QbD Assisted Development of Lipidic Nanocapsules for Antiestrogenic Activity of Exemestane in Breast Cancer

Some breast cancers are caused by hormonal imbalances, such as estrogen and progesterone.These hormones play a function in directing the growth of cancer cells. The hormone receptors in hormone receptor-positive breast cancer lead breast cells to proliferate out of control. Cancer therapy such as hormonal, targeted, radiation is still unsatisfactory because of these challenges viz. MDR (Multiple drug resistance), off-targeting, severe adverse effects. A novel aromatase inhibitor exemestane (Exe) exhibits promising therapy in breast cancer. This study aims to develop and optimize Exe-loaded lipid nanocapsules (LNCs) by using DSPC, PF68 and olive oil as lipid, surfactant and oil phase, respectively and to characterize the same. The prepared nanocapsules were investigated via in-vitro cell culture and in-vivo animal models. The LNCs exhibited cytotoxicity in MCF-7 cell lines and enhanced anti-cancer activity and reduced cardiotoxicity in DMBA-induced animal model when compared to the drug. Additionally, in-vivo pharmacokinetics revealed a 4.2-fold increased oral bioavailability when compared with Exe suspension. This study demonstrated that oral administration of Exe-loaded LNCs holds promise for the antiestrogenic activity of exemestane in breast cancer.

Toward Developing Discriminating Dissolution Methods for Formulations Containing Nanoparticulates in Solution: The Impact of Particle Drift and Drug Activity in Solution

Enabling formulations are an attractive approach to increase the dissolution rate, solubility, and oral bioavailability of poorly soluble compounds. With the growing prevalence of poorly soluble drug compounds in the pharmaceutical pipeline, supersaturating drug delivery systems (SDDS), a subset of enabling formulations, have grown in popularity due to their properties allowing for drug concentrations greater than the corresponding crystalline solubility. However, the extent of supersaturation generated as the enabling formulation traverses the gastrointestinal (GI) tract is dynamic and poorly understood. The dynamic nature of supersaturation is a result of several competing kinetic processes such as dissolution, solubilization by formulation and endogenous surfactants, crystallization, and absorption. Ultimately, the free drug concentration, which is equivalent to the drug's inherent thermodynamic activity amid these kinetic processes, defines the true driving force for drug absorption. However, in cases where solubilizing agents are present (i.e., surfactants and bile salts), drug molecules may associate with colloidal nanoscale species, complicating drug activity determination. These nanoscale species can drift into the aqueous boundary layer (ABL), increasing the local API activity at the membrane surface, resulting in increased bioavailability. Herein, a novel approach was developed to accurately measure thermodynamic drug activity in complex media containing drug distributed in nanoparticulate species. This approach captures the influence of the ABL on the observed flux and, ultimately, the predicted unbound drug concentration. The results demonstrate that this approach can help to (1) measure the true extent of local supersaturation in complex systems containing solubilizing excipients and (2) elucidate the mechanisms by which colloidal aggregates can modulate the drug activity in solution and potentially enhance the flux observed across a membrane. The utilization of these techniques may provide development scientists with a strategy to evaluate formulation sensitivity to nanospeciation and allow formulators to maximize the driving force for absorption in a complex environment, perhaps enabling the development of dissolution methods with greater discrimination and correlation to pre-clinical and clinical data sets.

Micelles entrapped microparticles technology: a novel approach to resolve dissolution and bioavailability problems of poorly water soluble drugs

Aim: Aim of this study was to design a solid oral delivery system for a weakly basic drug such as dasatinib (DAS), so as to achieve pH-independent dissolution and improved oral bioavailability.Methods: DAS was solubilised using sodium lauryl sulphate as an aqueous micellar system and such a system containing lactose monohydrate as carrier was spray-dried to obtain a solid mass. Subsequently, the DAS-solid was converted into a tablet using conventional tableting methods.Results: The dissolution study revealed pH-independent dissolution over a wide range of pH conditions. An in vivo bioavailability testing on rats revealed an improved C_max and AUC_0-24. Similarly, viability assay showed a better inhibitory effect of spray-dried dasatinib over the DAS.Conclusions: Micellar solubilisation and spray-drying technology can be approached to resolve poor dissolution and bioavailability of drugs belonging to biopharmaceutical classification system II and III. This technology is amenable to scale-up and has commercial potential.

Intestinal permeation enhancers for oral peptide delivery

Intestinal permeation enhancers (PEs) are one of the most widely tested strategies to improve oral delivery of therapeutic peptides. This article assesses the intestinal permeation enhancement action of over 250 PEs that have been tested in intestinal delivery models. In depth analysis of pre-clinical data is presented for PEs as components of proprietary delivery systems that have progressed to clinical trials. Given the importance of co-presentation of sufficiently high concentrations of PE and peptide at the small intestinal epithelium, there is an emphasis on studies where PEs have been formulated with poorly permeable molecules in solid dosage forms and lipoidal dispersions.

Impact of Solubilizing Additives on Supersaturation and Membrane Transport of Drugs

PURPOSE

Many enabling formulations give rise to supersaturated solutions wherein the solute possesses higher thermodynamic activity gradients than the solute in a saturated solution. Since flux across a membrane is driven by solute activity rather than concentration, understanding how solute thermodynamic activity varies with solution composition, particularly in the presence of solubilizing additives, is important in the context of passive absorption.

METHODS

In this study, a side-by-side diffusion cell was used to evaluate solute flux for solutions of nifedipine and felodipine in the absence and presence of different solubilizing additives at various solute concentrations.

RESULTS

At a given solute concentration above the equilibrium solubility, it was observed that the solubilizing additives could reduce the membrane flux, indicating that the extent of supersaturation can be reduced. However, the flux could be increased back to the same maximum value (which was determined by the concentration where liquid-liquid phase separation (LLPS) occurred) by increasing the total solute concentration. Qualitatively, the shape of the curves of solute flux through membrane as a function of total solute concentration is the same in the absence and presence of solubilizing additives. Quantitatively, however, LLPS occurs at higher solute concentrations in the presence of solubilizing additives. Moreover, the ratios of the LLPS onset concentration and equilibrium solubility vary significantly in the absence and presence of additives.

CONCLUSIONS

These findings clearly point out the flaws in using solute concentration in estimating solute activity or supersaturation, and reaffirm the use of flux measurements to understand supersaturated systems. Clear differentiation between solubilization and supersaturation, as well as thorough understanding of their respective impacts on membrane transport kinetics is important for the rational design of enabling formulations for poorly soluble compounds.

Aerosol-OT microemulsions as transdermal carriers of tetracaine hydrochloride

The aerosol-OT (AOT)/water/isopropyl myristate microemulsion was investigated as a carrier in transdermal drug delivery of tetracaine hydrochloride. The study included in vivo analgesic studies on rats and histopathological, irritation, and oxidative stress measurements on mice. The tetracaine hydrochloride encapsulated in AOT/water/isopropyl myristate showed an eightfold enhancement in the analgesic response of drug compared to the aqueous solution of the drug as measured by the tail-flick method. The analgesic response of tetracaine hydrochloride, however, highly depended on the concentration of AOT and water of the microemulsion. The preliminary histopathological, irritation, and oxidative stress studies showed that AOT/water/isopropyl myristate microemulsion system is a safe transdermal carrier of tetracaine hydrochloride with a concentration of AOT in isopropyl myristate up to 21:79 w/w.

Surfactant-induced increases of permeability of rat oral mucosa to non-electrolytes in vivo

The effect of non-ionic, cationic and anionic surfactants on non-electrolyte permeability of rat oral mucosa in vivo was tested. The surfactants caused an increase in mucosal permeability to oil-soluble compounds and small and large water-soluble compounds. The effect was concentration-dependent, and both the cationic and anionic surfactants were more potent than the non-ionic compounds. Surfactant-treated tissue showed widening of the stratum corneum due to separation of layers and loss of surface layers. Measurement of the permeability to sodium lauryl sulphate indicated that this anionic surfactant produced damage to the permeability barrier.

Effect of docusate sodium on drug release from a controlled-release dosage form

This study was designed to determine the effect of a clinically used surfactant, docusate sodium, on the release of chlorpheniramine from a controlled-release dosage form (encapsulated coated pellets). In vivo treatments consisted of the controlled-release capsule alone or with 200 mg of docusate sodium. Plasma chlorpheniramine levels were determined, and the AUC was calculated. No significant difference in AUC values was observed between the two treatments. At a concentration below the CMC, docusate sodium enhanced the in vitro drug release rate. The surfactant exerted a greater effect on the release of the first one-third of the drug contained in nonwax-coated pellets. At the CMC, 0.02% (w/v), docusate sodium rapidly entrapped chlorpheniramine in micelles. The overall enhanced dissolution rate in vivo may have been offset by micellar drug entrapment.

Percutaneous absorption of butylparaben through guinea pig skin in vitro

Percutaneous absorption of aqueous butylparaben through guinea pig dorsal skin was studied using a diffusion chamber. Polysorbate 80 increased the solubilized concentration but decreased penetration of the preservative. Polyethylene glycol 400 also reduced the amount of penetration. Propylene glycol was less effective than polyethylene glycol 400. Preservative activities of these systems on several microorganisms were evaluated on agar plates. The relationship between the butylparaben penetration and preservative activity is discussed.

Local adjuvants: the influence of sodium dodecylbenzene sulphonate on immunization with aerosolized antigen

Guinea-pig respiratory and serum antibody responses were enhanced following exposure to aerosols of bovine IgG2 dissolved in solutions of sodium dodecylbenzene sulphate (SDBS). Enhanced response was seen in both primary and secondary immunization. Cell-mediated immune response (indirect macrophage migration influencing test) was not altered by SDBS. Results are discussed with a view to the possible utility of SDBS as adjuvant for prophylactic immunization.

Validity of oral bioavailability estimates of phenolsulfonphthalein based on total urinary excretion from rats

Urinary recovery of phenolsulfonphthalein from rats were determined after intracardial (0.075 mg) and oral (1.5 mg) doses. Although trace quantities of conjugated metabolites could be identified by TLC, the levels present did not introduce significant error into estimates of total phenolsulfonphthalein excretion if samples were assayed directly by colorimetric methods for only unchanged dye. The absolute availability of phenolsulfonphthalein based on urinary recovery under the present experimental conditions was estimated at 10.6%.

Effect of dioctyl sodium sulfosuccinate and poloxamer 188 on dissolution and intestinal absorption of sulfadiazine and sulfisoxazole in rats

The influence of two medicinal surfactants, poloxamer 188 and dioctyl sodium sulfosuccinate, on the dissolution of sulfisoxazole and sulfadiazine was investigated. A dramatic increase in the dissolution rate was observed at all surfactant concentrations. Drug absorption from the rat small intestine was also studied, and a significant but less dramatic increase was noted. Dissolution rate and absorption could be correlated only qualitatively. The two surfactants had no effect on the amount of sulfisoxazole excreted by the rat in 24 hr.

Inhibitory effect of dioctyl sodium sulfosuccinate on trypsin activity

The inhibitory effect of dioctyl sodium sulfosuccinate on the proteolytic activity of trypsin was investigate over the pH 6-8 range. The antitryptic activity was determined using two different substrates: casein and N,alpha-benzoyl-DL-arginine-p-nitroanilide hydrochloride. The mechanistic studies revealed the substrate-inhibitor interaction to be the overall major mechanism of inhibition. This interaction was shown to involve substrate depletion, probably involving some primary sites of the natural substrate casein. Some inhibition was also shown to be due to an interaction between the enzyme and the inhibitior molecules. The interactions of the inhibitor with the enzyme and the substrate were irreversible. The possible therapeutic significance of the inhibitory effect of the surfactant is discussed.

Effect of surfactants on absorption through membranes IV: effects of dioctyl sodium sulfosuccinate on absorption of a poorly absorbable drug, phenolsulfonphthalein, in humans

To explore the effect of dioctyl sodium sulfosuccinate on drug absorption in humans, the urinary excretion of a poorly absorbable drug, phenolsulfonphthalein, administered in solution with and without the surfactant was determined. Coadministration of a therapeutic dose of the surfactant with the drug solution resulted in a significant increase in the initial rate of absorption. A small increase in the extent of absorption was also observed. Pretreatment with the surfactant for 6 nights, followed by administration of the drug on the 7th day, did not significantly change the rate of extent of absorption. The surfactant is thought to have a direct effect on the GI membrane, resulting in a temporary change in its permeability. This effect appears to be reversible after a few hours.