Application of SRMS 154 as Sustained Release Matrix for the Delivery of Stavudine: In vitro and in vivo Evaluation and Effect of Poloxamer 188 on the Properties of the Tablets

Assessment of the Anti-Malarial Properties of Dihydroartemisinin- Piperaquine Phosphate Solid Lipid-Based Tablets

BACKGROUND

Artemisininbased combination therapies (ACTs) typified by dihydroartemisinin- piperaquine phosphate are first-line drugs used in the treatment of Plasmodium falciparum malaria. However, the emergence of drug resistance to ACTs shows the necessity to develop novel sustained release treatments in order to ensure maximum bioavailability.

OBJECTIVES

To formulate dihydroartemisinin (DHA)-piperaquine phosphate (PQ) sustained release tablets based on solidified reverse micellar solutions (SRMS).

METHODS

The SRMS was prepared by fusion using varying ratios of Phospholipon® 90H and Softisan® 154 and characterised. The tablets were prepared by using an in-house made and validated mould. The formulations were tested for uniformity of weight, hardness, friability, softening time, erosion time and in vitro-in vivo dissolution rate. Antimalarial properties were studied using modified Peter's 4-days suppressive test in mice. One-way analysis of variance (ANOVA) was used in the analysis of results.

RESULTS

Smooth caplets, with average weight of 1300 ± 0.06 mg to 1312 ± 0.11 mg, drug content of 61 mg for DHA and t 450 mg for PQ. Tablet hardness ranged from 7.1 to 9.0 Kgf and softening time of 29.50 ± 1.90 min. Erosion time of 62.00 ± 2.58 to 152.00 ± 1.89 min were obtained for tablets formulated with Poloxamer 188 (Batches R2, S2 and T2) which significantly reduced the softening and erosion time (p < 0.05). In vitro release showed that the optimized formulations had a maximum release at 12 h. Formulations exhibited significantly higher parasitaemia clearance and in vivo absorption compared to marketed formulations at day 7 (p < 0.05).

CONCLUSION

DHA-PQ tablets based on SRMS were much easier and relatively cheaper to produce than compressed tablets. They also showed exceptionally better treatment of malaria owing to their sustained release properties and improved bioavailability and are recommended to Pharmaceutical companies for further studies.

A MSALL quantitative method for the determination of Poloxamer 188 in rat plasma by UHPLC-Q-TOF/MS and its application to pharmacokinetic study

Poloxamer (PL)188 is a commonly used pharmaceutical excipient with unique physicochemical properties. In this study, an MS^ALL quantitative method for the determination of PL188 in rat plasma by UHPLC-Q-TOF/MS was developed and validated. PL188 was analyzed on PLRP-S reversed-phase column (50 × 4.6 mm, 8 μm, 1,000 Å) with mobile phase 0.1% formic acid-water and 0.1% formic acid in acetonitrile-isopropanol (2:3, v/v). The liner range was 0.1-10.0 μg/ml. A pharmacokinetic study was performed on rats at a dose of 5 mg/kg by intravenous injection. The pharmacokinetic parameters of intravenous injection were as follows: half-life was 2.0 ± 1.1 h, volume of distribution was 5.1 ± 3.2 L/kg, area under the concentration-time curve was 3.0 ± 0.6 μg/L h and clearance was 1.7 ± 0.3 L/h/kg. The results indicated that PL188 could be rapidly distributed to tissues with a high clearance rate. This study can provide a good reference for the further study of PL188.

Anti-Inflammatory and Gastroprotective Properties of Aspirin - Entrapped Solid Lipid Microparticles

Background: Aspirin is a nonsteroidal anti-inflammatory drug that is very effective in the treatment of inflammation and other health conditions, however, it causes gastric irritation. Recently, researchers have developed patents (US9757529, 2019) of inhalable aspirin for rapid absorption and circumvention of gastric irritation.

Objective: The aim of this work was to formulate aspirin-loaded lipid based formulation in order to enhance oral bioavailability and inhibit gastric irritation.

Methods: This solid lipid microparticles loaded with aspirin (SLM) was formulated by a modified cold homogenization-solvent evaporation method. In vitro studies such as in vitro drug release, particle size, Encapsulation Efficiency (EE), micromeritic properties and loading capacity were carried out. Pharmacodynamics studies such as anti-inflammatory and ulcerative properties of the SLM were also carried out in Wistar rats.

Results: The results showed that aspirin entrapped SLM exhibited the highest EE of 72% and particle size range of 7.60 + 0.141µm to 20.25 + 0.070µm. Formulations had about 55% drug release at 6h in simulated intestinal fluid pH 6.8.The formulations had good flowability that could facilitate filling into hard gelatin capsule shells. The SLM exhibited 100% gastroprotection against aspirin-induced ulcers (p < 0.05). The percentage of anti-inflammatory activities also showed that aspirin-entrapped SLM had 78% oedema inhibition at 7h, while the reference had 68% inhibition at 7h.

Conclusion: Aspirin-entrapped SLM showed good sustained-release properties, enhanced anti-inflammatory properties and total gastric protection from aspirin-induced ulcers and could be used as once-daily oral aspirin.