PURPOSE: This scoping review aims to describe the effect of lipid-based formulations on the oral bioavailability of herbal compounds.
METHODS: A systematic search was conducted across three electronic databases (Medline, Embase and Cochrane Library) between January 2010 and January 2021 to identify relevant studies. The articles were rigorously screened for eligibility. Data from eligible studies were then extracted and collated for synthesis and descriptive analysis using Covidence.
RESULTS: A total of 109 studies were included in the present review: 105 animal studies and four clinical trials. Among the formulations investigated, 50% were emulsions, 34% lipid particulate systems, 12% vesicular systems, and 4% were other types of lipid-based formulations. Within the emulsion system classification, self-emulsifying drug delivery systems were observed to produce the best improvements in oral bioavailability, followed by mixed micellar formulations. The introduction of composite lipid-based formulations and the use of uncommon surfactants such as sodium oleate in emulsion preparation was shown to consistently enhance the bioavailability of herbal compounds with poor oral absorption. Interestingly, the lipid-based formulations of magnesium lithospermate B and Pulsatilla chinensis produced an absolute bioavailability greater than 100% indicating the possibility of prolonged systemic circulation. With respect to chemical conjugation, D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) was the most frequently used and significantly improved the bioavailability of its phytoconstituents.
CONCLUSION: Our findings suggest that there is no distinct lipid-based formulation superior to the other. Bioavailability improvements were largely dependent on the nature of the phytoconstituents. This scoping review, however, provided a detailed summary of the most up-to-date evidence on phytoconstituents formulated into lipid preparations and their oral bioavailability. We conclude that a systematic review and meta-analysis between bioavailability improvements of individual phytoconstituents (such as kaempferol, morin and myricetin) in various lipid-based formulations will provide a more detailed association. Such a review will be highly beneficial for both researchers and herbal manufacturers.
METHODS: This non-blinded, randomized clinical trial included 228 pregnant women at term with obstetric or medical indications for induction of labour. Women either took 50 µg misoprostol orally (two 25 µg tablets) or had one 25 µg tablet of misoprostol inserted in the posterior vaginal fornix. In each group, misoprostol administration was repeated every four hours in the same dose until regular uterine contractions were established or to a maximum of five doses. Time to delivery and outcome data for each group were compared.
RESULTS: Of the 228 women, eight (3.5%) were excluded from the analysis as they withdrew their consent after randomization. Mean induction-to-delivery interval was similar in both groups (21.22 hours in the oral group vs. 20.15 hours in the vaginal group; P = 0.58). There was no significant difference between the groups with respect to the number of women who delivered within 24 hours or who required oxytocin augmentation of labour, the mode of delivery, and neonatal outcomes (P > 0.05). Uterine hyperstimulation occurred in two women who received misoprostol vaginally, but not in any of the women in the oral misoprostol group.
CONCLUSION: Oral misoprostol in a dose of 50 µg every four hours, to a maximum of five doses, has the potential to induce labour as safely and effectively as 25 µg misoprostol administered vaginally every four hours.
MATERIALS AND METHODS: A Markov model was used to evaluate the economic and treatment outcomes of warfarin care bundles and NOACs compared with usual warfarin care. Cost-effectiveness was assessed from a societal perspective over a lifetime horizon with 3% discount rate in a hypothetical cohort of 65-year-old atrial fibrillation patients. Input parameters were derived from published literature, meta-analysis and local data when available. The outcome measure was incremental cost per quality-adjusted life years (QALY) gained (ICER).
RESULTS: Using USD5104 as the threshold of willingness-to-pay per QALY, patient's self-management of warfarin was cost-effective when compared to usual warfarin care, with an ICER of USD1395/QALY from societal perspective. All NOACs were not cost-effective in Thailand, with ICER ranging from USD8678 to USD14,247/QALY. When compared to the next most effective intervention, patient's self-testing and genotype-guided warfarin dosing were dominated. In the cost-effectiveness acceptability curve, patient's self-management had the highest probability of being cost-effective in Thailand, approximately 78%. Results were robust over a range of inputs in sensitivity analyses.
CONCLUSIONS: In Thailand, NOACs were unlikely to be cost-effective at current prices. Conversely, patient's self-management is a highly cost-effective intervention and may be considered for adoption in developing regions with resource-limited healthcare systems.
Objective: The current study was conducted to evaluate acute oral toxicity of LA on normal rats.
Methods: The study was conducted in accordance with the Organization for Economic Co-operation and Development guidelines (OECD 423) with slight modifications. LA was administered orally to female Sprague Dawley (SD) rats (n = 6/group) at a single dose of 300 and 2,000 mg/kg body weight, respectively, while normal control received vehicle only. Animals from all the three groups were monitored for any behavioural and toxicological changes and mortality for two weeks. Food and fluid consumption, body weight was monitored on daily basis. At the end (on day 15th) of the experimental period, blood was collected for haematological and biochemical analysis. Further, all the animals were euthanized, and internal organs were harvested for histopathological investigation using four different stainings; haematoxylin and eosin, Masson trichrome, Periodic Acid Schiff and Picro Sirius Red for gross pathology through microscopical observation.
Results: The study results showed no LA treatment-related mortality and morbidity at two different dosages. Daily food and water consumption, body weight, relative organ weight, haematological, and biochemical analysis were observed to be normal with no severe alterations to the internal tissues.
Conclusion: The current finding suggests that single oral administration of LA, even up to 2,000 mg/kg body weight, did not exhibit any signs of toxicity in SD rats; thus, it was safe to be used on disease models in animals.
METHODS: This study describes the formulation design, optimisation, characterisation and evaluation of insulin concentration via oral delivery in rats. A reversed-phase high-performance liquid chromatography (HPLC) method was developed and validated to quantify insulin concentration in rat plasma. The proposed method produced a linear response over the concentration range of 0.39 to 50 µg/ml.
RESULTS: In vitro release study showed that dissolution of insulin in simulated gastric juice of pH 1.2 was prevented by alginate core and chitosan coating but rapidly released in simulated intestinal fluid (pH 6.8). Additionally, Formulation 3 (F3) has a particle size of 340.40 ± 2.39 nm with narrow uniformity exhibiting encapsulation efficiency (EE) of 72.78 ± 1.25 % produced highest absorption profile of insulin with a bioavailability of 40.23 ±1.29% and reduced blood glucose after its oral administration in rats.
CONCLUSION: In conclusion, insulin oral delivery system containing alginate and chitosan as a coating material has the ability to protect the insulin from enzymatic degradation thus enhance its absorption in the intestine. However, more work should be done for instance to involve human study to materialise this delivery system for human use.