Development and characterization of zaleplon solid dispersion systems: a technical note

Polymeric nanoencapsulation of zaleplon into PLGA nanoparticles for enhanced pharmacokinetics and pharmacological activity

Zaleplon (ZP) is a sedative and hypnotic drug used for the treatment of insomnia. Despite its potent anticonvulsant activity, ZP is not commonly used for the treatment of convulsion since ZP is characterized by its low oral bioavailability as a result of poor solubility and extensive liver metabolism. The following study aimed to formulate specifically controlled release nano-vehicles for oral and parenteral delivery of ZP to enhance its oral bioavailability and biological activity. A modified single emulsification-solvent evaporation method of sonication force was adopted to optimize the inclusion of ZP into biodegradable nanoparticles (NPs) using poly (dl-lactic-co-glycolic acid) (PLGA). The impacts of various formulation variables on the physicochemical characteristics of the ZP-PLGA-NPs and drug release profiles were investigated. Pharmacokinetics and pharmacological activity of ZP-PLGA-NPs were studied using experimental animals and were compared with generic ZP tablets. Assessment of gamma-aminobutyric acid (GABA) level in plasma after oral administration was conducted using enzyme-linked immunosorbent assay. The maximal electroshock-induced seizures model evaluated anticonvulsant activity after the parenteral administration of ZP-loaded NPs. The prepared ZP-PLGA NPs were negatively charged spherical particles with an average size of 120-300 nm. Optimized ZP-PLGA NPs showed higher plasma GABA levels, longer sedative, hypnotic effects, and a 3.42-fold augmentation in oral drug bioavailability in comparison to ZP-marketed products. Moreover, parenteral administration of ZP-NPs showed higher anticonvulsant activity compared to free drug. Oral administration of ZP-PLGA NPs achieved a significant improvement in the drug bioavailability, and parenteral administration showed a pronounced anticonvulsant activity.

Enhancement of zaleplon oral bioavailability using optimized self-nano emulsifying drug delivery systems and its effect on sleep quality among a sample of psychiatric patients

The aim of this work is to develop self-nano emulsifying drug delivery system (SNEDDS) to enhance the oral bioavailability of zaleplon (Zal) as a poorly water-soluble drug. Moreover, the bioavailability and the effect on the quality of sleep among a sample of psychiatric patients is to be assessed. D-optimal mixture design was used for optimization. Optimized SNEDDS formulation was evaluated for droplet size, transmission electron microscope (TEM) and in-vitro dissolution test. Zal bioavailability was evaluated by determining its serum concentration and pharmacokinetic parameters in 8 patients after oral administration. Effect on sleep quality was assessed among 40 psychiatric patients. Patients’ sleep quality was assessed in 40 psychiatric patients before and after medication using the Arabic version of the Pittsburgh Sleep Quality Index (PSQI). Zal- SNEDDS appeared as nano-sized spherical vesicles. Moreover, Zal was completely dissolved from optimized formulation after 45 min indicating improved dissolution rate. Zal-SNEDDS showed significantly higher C_max, T_max and AUC_0→∞ compared to commercial product after oral administration. Zal-SNEDDS significantly improved the total score of PSQIs (p < .001) with higher subjective sleep quality, reduced sleep latency, improved day time function and sleep disturbance (p < .001). Using sleep medication was reduced significantly (p = .027). However, it did not modify sleep duration or sleep efficiency. SNEDDS have improved Zal solubility and enhanced its bioavailability. Furthermore, Zal-SNEDDS have improved the total score of PSQIs and may be considered a good choice to enhance the quality of sleep among psychiatric patients.

Micronized Zaleplon Delivery via Orodispersible Film and Orodispersible Tablets

The following research study focuses on improving the solubility of zaleplon (BCS class II drug) via micronization technique in order to enhance its oral delivery in orodispersible formulations. Zaleplon along with a surfactant solution was micronized by ultrasonication. The micronization process reduced the particle size of the crystalline drug about six-fold from its original size of 155.5 μm. The micronized zalepon dispersion was lyophilized to allow for a change in the state of matter (to a powder). The superior dissolution parameters (Q₅, Q₃₀, IDR, MDR, MDT, DE, and RDR) of zaleplon in microcrystalline form over the original crystalline form in in vitro dissolution studies had unraveled that micronization technique is an efficient tool in enhancing drug solubility. The micronized zaleplon solid dispersion (after lyophilization) was loaded into orodispersible tablet (ODT) and orodispersible film (ODF) formulations. The positive quality of ODT with adequate hardness and smooth texture was attributing to the presence of Pearlitol Flash® as a ready to use ODT platform. On the other hand, the ODF loaded with micronized zaleplon and prepared with Lycoat® RS 720 (as a film former) ensured adequate tensile strength. The disintegration time of ODT and ODF was 30 ± 5 and 35 ± 5 s, respectively. Thus, the orodispersible formulations containing micronized zaleplon have a strong potential for rapid disintegration following superior absorption in solution state through oral cavity into the blood stream, envisaging better oral delivery.