In-situ gel of nifedipine for preeclampsia: Optimization, in-vitro and in-vivo evaluation

Rational Design of Nanomedicine for Placental Disorders: Birthing a New Era in Women's Reproductive Health

The placenta is a transient organ that forms during pregnancy and acts as a biological barrier, mediating exchange between maternal and fetal circulation. Placental disorders, such as preeclampsia, fetal growth restriction, placenta accreta spectrum, and gestational trophoblastic disease, originate in dysfunctional placental development during pregnancy and can lead to severe complications for both the mother and fetus. Unfortunately, treatment options for these disorders are severely lacking. Challenges in designing therapeutics for use during pregnancy involve selectively delivering payloads to the placenta while protecting the fetus from potential toxic side effects. Nanomedicine holds great promise in overcoming these barriers; the versatile and modular nature of nanocarriers, including prolonged circulation times, intracellular delivery, and organ-specific targeting, can control how therapeutics interact with the placenta. In this review, nanomedicine strategies are discussed to treat and diagnose placental disorders with an emphasis on understanding the unique pathophysiology behind each of these diseases. Finally, prior study of the pathophysiologic mechanisms underlying these placental disorders has revealed novel disease targets. These targets are highlighted here to motivate the rational design of precision nanocarriers to improve therapeutic options for placental disorders.

In situ gastric floating gel of atazanavir sulphate for sustained release: formulation, optimization and evaluation

Aim: Atazanavir sulphate belongs to BCS class II drug, its oral bioavailability is limited due to its rapid first-pass metabolism and P-gp efflux. Materials & methods: The in situ floating gel using the complexed drug was prepared by ion gelation method and optimized the formulation as per 32 full factorial design. Results: Floating lag time of optimized formulation was found to be 18 s and percentage drug release of 94.18 ± 0.18 % at the end of 16 h. The concentration of gelling polymer affects drug release and a floating lag time and vice versa. Conclusion: In situ floating gel of atazanavir sulphate was found promising to sustain drug release due to an increased gastric residence time, which leads to enhanced potential therapy.

Solid lipid nanoparticles cyclodextrin-decorated incorporated into gellan gum-based dry floating in situ delivery systems for controlled release of bioactive compounds of safflower (Carthamus tinctorius. L): A proof of concept study in biorelevant media

Safflower (Carthamus tinctorius L.) has been explored as a source of natural antioxidant. However, quercetin 7-O-beta-D-glucopyranoside and luteolin 7-O-beta-D-glucopyranoside, as its bioactive compounds, possessed poor aqueous solubility, limiting its efficacy. Here, we developed solid lipid nanoparticles (SLNs) decorated with hydroxypropyl beta-cyclodextrin (HPβCD) incorporated into dry floating gel in situ systems to control the release of both compounds. Using Geleol® as a lipid matrix, SLNs were <200 nm in size with >80 % of encapsulation efficiency. Importantly, following the decoration using HPβCD, the stability of SLNs in gastric environment was significantly improved. Furthermore, the solubility of both compounds was also enhanced. The incorporation of SLNs into gellan gum-based floating gel in situ provided desired flow and floating properties, with <30 s gelation time. The floating gel in situ system could control the release of bioactive compounds in FaSSGF (Fasted-State Simulated Gastric Fluid). Furthermore, to assess the effect of food intake on release behavior, we found that the formulation could show a sustained release pattern in FeSSGF (Fed-State Simulated Gastric Fluid) for 24 h after being released in FaSGGF for 2 h. This indicated that this combination approach could be a promising oral delivery for bioactive compounds in safflower.

Response Surface Methodology for Optimization of Buspirone Hydrochloride-Loaded In Situ Gel for Pediatric Anxiety

The purpose of the current investigation was to formulate, assess, and optimize oral in situ gels of buspirone hydrochloride (BH) with the specific end goal of expanding the time the medication spends in the stomach, thereby ensuring an extended medication discharge. This would allow the use of a once-a-day dose of liquid BH formulations, which is ideal for the treatment of pediatric anxiety. In situ gels loaded with BH were prepared using various concentrations of sodium alginate (Na alg.), calcium chloride (CaCl₂), and hydroxypropyl methylcellulose (HPMC K15M). The in situ gels exhibited the desired consistency, drug distribution, pH, ability to form gel, and prolonged drug release in vitro. The (3³) full factorial design was utilized for the revealing of the ideal figures for the selected independent variables, Na alg. (X₁), HPMC (X₂), and CaCl₂ (X₃) based on measurements of the viscosity (Y₁) and percentage drug release after 6 h (Y₂). A pharmacokinetic study of the optimum formulation on rabbits was also performed. The formulation containing 2% of Na alg., 0.9% of HPMC-K15M, and 0.1125% of CaCl₂ was selected as the ideal formulation, which gave the theoretical values of 269.2 cP and 44.9% for viscosity and percentage of drug released after 6 h, respectively. The pharmacokinetic study showed that the selected oral Na alg. in situ gel formulation displayed a prolonged release effect compared to BH solution and the marketed tablet (Buspar^®), which was confirmed by the low C_max and high T_max values. The optimum oral Na alg. in situ gel showed a 1.5-fold increment in bioavailability compared with the drug solution.

Formulation, optimization and validation of floating oral in situ gel of Ivabradine hydrochloride

Aim: Ivabradine hydrochloride is a hyperpolarized activated channel blocker used for symptomatic treatment of chronic angina pectoris. However, due to its short half-life it is rapidly eliminated from systemic circulation. Materials & methods: Floating in situ gel was formulated using sodium alginate and HPMC K 100 M by pH induced ion gelation technique employing 3² factorial design for optimization and evaluated. Results: The in situ formulation remained buoyant in gastric environment for 12 h. Optimized formulation sustained and prolonged drug release in comparison with marketed product. Kinetic analysis of drug release indicated non fickian mechanism. Short term stability studies showed no significant changes indicating good formulation stability. Conclusion: Formulated in situ solution shows potential effective sustained release over a prolonged period of time.

A novel in vitro approach to investigate the effect of food intake on release profile of valsartan in solid dispersion-floating gel in-situ delivery system

Valsartan (VAL) is a BCS class II drug with low solubility and high permeability and, thus, its formulations often encounter low bioavailability problems. Its low bioavailability can be improved through enhanced formulation, such as incorporating it into a solid dispersion system (SD). The absorption can be further enhanced through gastroretentive systems. Herein, we developed a novel combination delivery approach consisting of floating in-situ gel and SD. VAL was incorporated with polymer carrier PVP and PEG 6000 and its solubility was then evaluated. The study found that VAL-SD containing PVP K-30 as the carrier with drug:PVP K-30 ratio of 1:3 shown highest solubility in different media. Moreover, DSC and XRD evaluations exhibited the change of VAL from crystal to amorphous following SD formulation. The SD was then formulated into floating in-situ gel preparations using sodium alginate as gel forming compound and HPMC as the controlled release matrix. The prepared VAL-SD floating in-situ gels were evaluated for their physical properties and drug release profile. The results showed that all physical evaluation of the floating in-situ gel formula possessed desirable physical properties and the use of HPMC in floating in-situ gel was able to sustain the in vitro release of VAL for 24 h in biorelevant media. Importantly, the effect of food intake on VAL release was also investigated, for the first time, showing that the VAL release could be controlled in FaSSGF (Fasted-State Simulated Gastric Fluid) in 2 h and FeSSGF (Fed-State Simulated Gastric Fluid) onwards. Thus, in can be hypothesized that the food intake did not affect the VAL release after 2 h in an empty gastric environment. Leading on from these results, in vivo studies in an animal model should be carried out to further assess the potency of this system.

Repurposing of nifedipine loaded in situ ophthalmic gel as a novel approach for glaucoma treatment

Glaucoma is a chronic eye disease characterized by elevated intraocular pressure (IOP) which causes severe complications to the eyes and may lead to vision loss. The effective treatment of such diseases motivated the search for novel and unique drugs and delivery systems. It has been reported that, nifedipine (NF) is effective in reducing the elevated IOP due to vasodilatation of eye vascular smooth muscles. NF loaded thermo-sensitive in situ gels were prepared by the cold method using poloxamer 407 (P407) and hydroxypropyl methyl cellulose (HPMC) polymers adopting Box-Behnken experimental design. All the prepared formulae were tested for homogeneity, clarity, pH, isotonicity, gelling capacity, rheological behavior, in vitro drug release and were tested in vivo on rabbits. The prepared in situ gels were homogenous, transparent, having a pH ranged from 5 to 5.5 and undergo sol-gel transition within few seconds physiological temperature. The in situ gels showed sustained in vitro release of NF where about 76% of the loaded drug was released over 12 h. NF loaded in situ gels showed a 45.83 ± 2.91% reduction in the IOP, with no sign of toxicity or irritation to the eye in rabbits. The current investigations clarified the efficiency of this novel and unique NF loaded in situ gel for the control of the IOP compared to the conventional ophthalmic dosage forms.

Promising Polymeric Drug Carriers for Local Delivery: The Case of in situ Gels

BACKGROUND

At present, the controlled local drug delivery is a very promising approach compared to systemic administration, since it mostly targets the affected tissue. In fact, various drug carriers for local delivery have been prepared with improved therapeutic efficacy.

OBJECTIVE

in situ polymer gels are drug delivery systems that not only present liquid characteristics before their administration in body, but once they are administered, form gels due to gelation. Their gelation mechanism is due to factors such as pH alteration, temperature change, ion activation or ultraviolet irradiation. in situ gels offer various advantages compared to conventional formulations due to their ability to release drugs in a sustainable and controllable manner. Most importantly, in situ gels can be used in local drug delivery applications for various diseases.

METHODS

This review includes the basic knowledge and theory of in situ gels as well as their various applications according to their administration route.

RESULTS

Various natural, semisynthetic, and synthetic polymers can produce in situ polymeric gels. For example, natural polysaccharides such as alginic acid, chitosan, gellan gum, carrageenan etc. have been utilized as in situ gels for topical delivery. Besides the polysaccharides, poloxamers, poly(Nisopropylacrylamide), poly(ethyleneoxide)/ (lactic-co-glycolic acid), and thermosensitive liposome systems can be applied as in situ gels. In most cases, in situ polymeric gels could be applied via various administration routes such as oral, vaginal, ocular, intranasal and injectable.

CONCLUSION

To conclude, it can be revealed that in situ gels could be a promising alternative carrier for both chronic and immediate diseases.

Gellan gum based gastroretentive tablets for bioavailability enhancement of cilnidipine in human volunteers

Cilnidipine, a fourth-generation both L-and N-type calcium channel blocker (CCB) is safe and effective in lowering blood-pressure without reflex tachycardia compared to other dihydropyridine CCBs. However, its low solubility coupled with extensive first-pass metabolism results in very low oral bioavailability. Thus the study aimed to improve oral bioavailability of Cilnidipine by increasing its gastrointestinal transit-time and mucoadhesion. Gastroretentive tablets were prepared by direct-compression technique using gellan gum as hydrogel forming polymer and sodium bicarbonate as gas-generating agent. Statistical optimization was carried out by design approach which showed that gellan gum has significant impact on floating lag time, mucoadhesive strength, % drug release at 1 h and time to release 90% of drug. Drug release study revealed that optimized tablets prolonged drug release for 12 h and followed anomalous-diffusion indicating drug release is by coupling of both diffusion and erosion mechanism. Intragastric behaviour of formulation in human volunteers revealed that radio-opaque tablets remain buoyant in stomach for more than 6 h with sufficient mucoadhesion. Comparative pharmacokinetic profiling in human subjects revealed that relative bioavailability of Cilnidipine GR tablets was enhanced compared to reference tablets. Thus concluded that gastroretentive tablets to be promising strategy for improved oral bioavailability of Cilnidipine for effective treatment of hypertension.