Clozapine-Encapsulated Binary Mixed Micelles in Thermosensitive Sol-Gels for Intranasal Administration

Phase transforming in situ gels for sustained and controlled transmucosal drug delivery via the intravaginal route

Direct, reliable, controlled, and sustained drug delivery to female reproductive tract (FRT) remains elusive, with conventional dosage forms falling way short of the mark, leading to premature leakage, erratic drug delivery, and loss of compliance. Historically, the intravaginal route remains underserved by the pharmaceutical sector. To comprehensively address this, we turned our focus to phase-transforming sol-gels, using poloxamers, a thermosensitive polymer and, doxycycline (as hyclate salt, DOXH) as our model agent given its potential use in sexually transmitted infections (STIs). We further enhanced mucoadhesiveness through screening of differing viscosity grade hydroxypropyl methyl celluloses (HPMCs). The optimised sol-gels remained gelled at body temperature (<37 °C) and were prepared in buffer aligned to vaginal cavity pH and osmolality. Lead formulations were progressed based on their ability to retain key rheological properties, and acidic pH in the presence of simulated vaginal fluid (SVF). From a shelf-life perspective, DOXH stability, gelation temperature (Tsol-gel), and pH to three months (2-8 °C) was attained. In summary, the meticulously engineered, phase-transforming sol-gels provided sustained mucoretention despite dilution by vaginal fluid, paving the way for localised antimicrobial drug delivery at concentrations that potentially far exceed the minimum inhibitory concentration (MIC) for target STI-causing bacteria of the FRT.

LA67 Liposome-Loaded Thermo-Sensitive Hydrogel with Active Targeting for Efficient Treatment of Keloid via Peritumoral Injection

A keloid is a benign tumor manifested as abnormal fibroplasia on the surface of the skin. Curing keloids has become a major clinical challenge, and searching for new treatments and medications has become critical. In this study, we developed a LA67 liposome-loaded thermo-sensitive hydrogel (LA67-RL-Gel) with active targeting for treating keloids via peritumoral injection and explored the anti-keloid mechanism. Firstly, Arg-Gly-Asp (RGD) peptide-modified liposomes (LA67-RL) loaded with LA67 were prepared with a particle size of 105.9 nm and a Zeta potential of -27.4 mV, and an encapsulation efficiency of 89.6 ± 3.7%. We then constructed a thermo-sensitive hydrogel loaded with LA67-RL by poloxamer 407 and 188. The formulation was optimized through the Box-Behnken design, where the impact of the proportion of the ingredients on the quality of the hydrogel was evaluated entirely. The optimal formulation was 20.7% P407 and 2.1% P188, and the gelation time at 37 °C was 9.5 s. LA67-RL-Gel slowly released 92.2 ± 0.8% of LA67 at pH 6.5 PBS for 72 h. LA67-RL-Gel increased adhesion with KF cells; increased uptake; promoted KF cells apoptosis; inhibited cell proliferation; reduced α-SMA content; decreased collagen I, collagen III, and fibronectin deposition; inhibited angiogenesis; and modulated the keloid microenvironment, ultimately exerting anti-keloid effects. In summary, this simple, low-cost, and highly effective anti-keloid liposome hydrogel provides a novel approach for treating keloids and deserves further development.

Development of Lyophilised Eudragit® Retard Nanoparticles for the Sustained Release of Clozapine via Intranasal Administration

Clozapine (CZP) is the only effective drug in schizophrenia resistant to typical antipsychotics. However, existing dosage forms (oral or orodispersible tablets, suspensions or intramuscular injection) show challenging limitations. After oral administration, CZP has low bioavailability due to a large first-pass effect, while the i.m. route is often painful, with low patient compliance and requiring specialised personnel. Moreover, CZP has a very low aqueous solubility. This study proposes the intranasal route as an alternative route of administration for CZP, through its encapsulation in polymeric nanoparticles (NPs) based on Eudragit^® RS100 and RL100 copolymers. Slow-release polymeric NPs with dimensions around 400-500 nm were formulated to reside and release CZP in the nasal cavity, where it can be absorbed through the nasal mucosa and reach the systemic circulation. CZP-EUD-NPs showed a controlled release of CZP for up to 8 h. Furthermore, to reduce mucociliary clearance and increase the residence time of NPs in the nasal cavity to improve drug bioavailability, mucoadhesive NPs were formulated. This study shows that the NPs already exhibited strong electrostatic interactions with mucin at time zero due to the presence of the positive charge of the used copolymers. Furthermore, to improve the solubility, diffusion and adsorption of CZPs and the storage stability of the formulation, it was lyophilised using 5% (w/v) HP-β-CD as a cryoprotectant. It ensured the preservation of the NPs' size, PDI and charge upon reconstitution. Moreover, physicochemical characterisation studies of solid-state NPs were performed. Finally, toxicity studies were performed in vitro on MDCKII cells and primary human olfactory mucosa cells and in vivo on the nasal mucosa of CD-1 mice. The latter showed non-toxicity of B-EUD-NPs and mild CZP-EUD-NP-induced tissue abnormalities.

Intranasal in situ gelling liquid crystal for delivery of resveratrol ameliorates memory and neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) is an illness that affects people aged 65 or older and affects around 6.5 million in the United States. Resveratrol is a chemical obtained from natural products and it exhibits biological activity based on inhibiting the formation, depolymerization of the amyloid, and decreasing neuroinflammation. Due to the insolubility of this compound; its incorporation in surfactant-based systems was proposed to design an intranasal formulation. A range of systems has been produced by mixing oleic acid, CETETH-20 and water. Polarised light microscopy (PLM), small angle x-ray scattering (SAXS) and transmission electron microscopy (TEM) confirm the initial liquid formulation (F) presented as microemulsion (ME). After dilution, the gelled systems were characterized as hexagonal mesophase and they showed feasibility proprieties. Pharmacological assays performed after intranasal administration showed the ability to improve learning and memory in animals, as well as remission of neuroinflammation via inhibition of interleukin.

Self-Assembling Lecithin-Based Mixed Polymeric Micelles for Nose to Brain Delivery of Clozapine: In-vivo Assessment of Drug Efficacy via Radiobiological Evaluation

Purpose

The research objective is to design intranasal brain targeted CLZ loaded lecithin based polymeric micelles (CLZ- LbPM) aiming to improve central systemic CLZ bioavailability.

Methods

In our study, intranasal CLZ loaded lecithin based polymeric micelles (CLZ- LbPM) were formulated using soya phosphatidyl choline (SPC) and sodium deoxycholate (SDC) with different CLZ:SPC:SDC ratios via thin film hydration technique aiming to enhance drug solubility, bioavailability and nose to brain targeting efficiency. Optimization of the prepared CLZ-LbPM using Design-Expert® software was achieved showing that M6 which composed of (CLZ:SPC: SDC) in respective ratios of 1:3:10 was selected as the optimized formula. The optimized formula was subjected to further evaluation tests as, Differential Scanning Calorimetry (DSC), TEM, in vitro release profile, ex vivo intranasal permeation and in vivo biodistribution.

Results

The optimized formula with the highest desirability exhibiting (0.845), small particle size (12.23±4.76 nm), Zeta potential of (-38 mV), percent entrapment efficiency of > 90% and percent drug loading of 6.47%. Ex vivo permeation test showed flux value of 27 μg/cm².h and the enhancement ratio was about 3 when compared to the drug suspension, without any histological alteration. The radioiodinated clozapine ([¹³¹I] iodo-CLZ) and radioiodinated optimized formula ([¹³¹I] iodo-CLZ-LbPM) were formulated in an excellent radioiodination yield more than 95%. In vivo biodistribution studies of [¹³¹I] iodo-CLZ-LbPM showed higher brain uptake (7.8%± 0.1%ID/g) for intranasal administration with rapid onset of action (at 0.25 h) than the intravenous formula. Its pharmacokinetic behavior showed relative bioavailability, direct transport percentage from nose to brain and drug targeting efficiency of 170.59%, 83.42% and 117% respectively.

Conclusion

The intranasal self-assembling lecithin based mixed polymeric micelles could be an encouraging way for CLZ brain targeting.

Alternative Routes of Administration of Clozapine

Clozapine is the only antipsychotic with proven effectiveness in treatment-resistant schizophrenia. It is usually administered using commercially available oral tablets, but not all patients are willing or able to take medicines in this way. Orodispersible clozapine tablets are available from several manufacturers and may be useful where swallowing solid dosage forms is difficult, or as an aid to observe compliance. Liquid formulations of clozapine can be prepared extemporaneously or purchased commercially, but most preparations are suspensions (clozapine is poorly soluble) and patients may find them unpalatable. The administration of clozapine (suspension or crushed tablets) via enteral feeding tubes (predominantly nasogastric) has been reported both in medically unwell patients and in patients refusing clozapine. Enteral administration is likely to be superseded by intramuscular clozapine, which has recently been re-introduced and is being widely used in some countries. Successful use of this formulation in enforced treatment strategies has been described by several authors with good long-term outcomes when switched to oral treatment. Intramuscular clozapine has also been used in physically ill patients who are unable to take any form of enteral medication. Other methods of delivery (transdermal, nasal) are not yet commercially available, but offer promise of further treatment options for this group of seriously ill patients.