The possibility of delivering levothyroxine avoiding the digestive system has many advantages. These include interference with food, drinks, other medicines, supplements, etc. Also the possible effects of levothyroxine on the gut ling and biome.
It
will take years of research for any products to reach market. Even
then, most novel medicines, even if just a different route of delivery,
cost considerably more than existing products. Therefore access will be
limited by wealth of countries and, within countries, wealth of patients
or other funding mechanisms
To this end, there have been a number of trials of possible ways of delivering levothyroxine transdermally.
I used the following search (which will return updated results each time it is run).
https://europepmc.org/search?query=transdermal%20levothyroxine
The most obvious results of interest were:
The following paper has just been added:
Effects and Action Mode of Oleic Acid and Azone on Release and Penetration Process of Levothyroxine Sodium Patches
In recent years, there has been a significant increase in the prevalence of thyroid diseases, particularly hypothyroidism. In this study, we investigated the impact and mechanisms of Chemical permeation enhancement(CPE) on transdermal permeation of levothyroxine sodium (L-T4) patches.We found that the combination of oleic acid (OA) and Azone (NZ) yielded the best transdermal permeation effect for L-T4.Subsequently, we also investigated the relevant propermeability mechanism.The results demonstrate that the combined application of OA and NZ significantly enhances the transdermal permeation of L-T4 compared to individual applications,it is attributed to two mechanisms: firstly, OA improves drug release by increasing the flowability of the pressure-sensitive adhesive (PSA) matrix; secondly, both OA and NZ act on the stratum corneum, especially facilitating L-T4 permeation through the hair follicle pathway. No skin irritation or cytotoxicity is observed with these final patches, which exhibit a remarkable therapeutic effect on hypothyroidism. this study contributes to the development of transdermal formulations of L-T4.
Full paper is behind a paywall.
https://link.springer.com/article/10.1208/s12249-024-02875-x
Film-Forming Systems for Dermal Drug Delivery
Film-forming formulations represent a novel form of sustained release dermatic products. They are applied to the skin as a liquid or semi-solid preparation. By evaporation of the volatile solvent on the skin, the polymer contained in the formulation forms a solid film. Various film-forming formulations were tested for their water and abrasion resistance and compared with conventional semi-solid formulations. Penetration and permeation studies of the formulations indicate a potential utility as transdermal therapeutic systems. They can be used as an alternative to patch systems to administer a variety of drugs in a topical way and may provide sustained release characteristics.
https://europepmc.org/article/MED/34201668
Levothyroxine sodium loaded dissolving microneedle arrays for transdermal delivery.
Levothyroxine (LT-4) sodium has shown variable bioavailability following oral administration. This can be assigned to the significant influence of gastrointestinal conditions, food and drugs administered concomitantly on the rate and extent of absorption from the gastrointestinal tract. Thus, the aim of this research study was to establish an efficient transdermal delivery system of LT-4 sodium via the application of hyaluronic acid dissolving microneedles. Microneedles-based drug delivery system consists of sharp-tip needles that puncture the top layers of the skin in a minimally invasive manner to create physical channels through which therapeutic molecules can easily diffuse into/across the skin. Hyaluronic acid polymer at different ratios (5-60 %) was used to prepare microneedle arrays (100 needles per array) using a micromoulding technique. Characterisation tests were carried out to select the optimum formulation. F11 formula containing 50% w/v hyaluronic acid and 1% v/v Tween 80 formula showed an appropriate needle shape with dimensions of 432 ± 6.4 μm in height and a tip diameter of 9.8 ± 1.3 μm. The microneedle arrays demonstrated a suitable mechanical strength after applying a force of 32 N per array and an excellent insertion ability both in Parafilm M® and human skin. The in vivo dissolution of microneedles was started rapidly within 5 minutes following the insertion in the skin and completed at 1 hour. Ex vivo permeation study using human skin has shown a significant improvement in LT-4 sodium delivery across the skin compared to control preparations (drug solution and microneedle free film). The microneedle array F11 has significantly (P ≤ 0.05) increased LT-4 sodium permeation through the skin (cumulative permeated amount of 32 ± 2 μg/cm2) in comparison to the control solution (cumulative permeated amount of 0.7 ± 0.07 μg/cm2) and the microneedle free film (cumulative permeated amount of 0.1 ± 0.02 μg/cm2) over 7 hours. The findings from the irritation test revealed that mild erythema was produced from the application of microneedle arrays which disappeared within 24 hours. Accordingly, dissolving hyaluronic acid microneedles could be a feasible and effective approach to delivering LT-4 sodium transdermally without causing significant skin damage.
https://europepmc.org/article/MED/36131889
Levothyroxine: Conventional and Novel Drug Delivery Formulations.
Although levothyroxine is one of the most prescribed medications in the world, its bioavailability has been reported to be impaired by many factors, including interfering drugs or foods and concomitant diseases, and persistent hypothyroidism with a high dose of levothyroxine is thus elicited. Persistent hypothyroidism can also be induced by noninterchangeability between formulations and poor compliance. To address these issues some strategies have been developed. Novel formulations (liquid solutions and soft gel capsules) have been designed to eliminate malabsorption. Some other delivery routes (injections, suppositories, sprays, and sublingual and transdermal administrations) are aimed at circumventing different difficulties in dosing, such as thyroid emergencies and dysphagia. Moreover, nanomaterials have been used to develop delivery systems for the sustained release of levothyroxine to improve patient compliance and reduce costs. Some delivery systems encapsulating nanoparticles show promising release profiles. In this review, we first summarize the medical conditions that interfere with the bioavailability of oral levothyroxine and discuss the underlying mechanisms and treatments. The efficacy of liquid solutions and soft gel capsules are systematically evaluated. We further summarize the novel delivery routes for levothyroxine and their possible applications. Nanomaterials in the levothyroxine field are then discussed and compared based on their load and release profile. We hope the article provides novel insights into the drug delivery of levothyroxine.
https://europepmc.org/article/MED/36412275
Preparation and in vitro evaluation of injectable formulations of levothyroxine sodium using in situ forming hydrogel temperature-responsive systems based on PLA-PEG-PLA and PLGA-PEG-PLGA triblock copolymers.
Objectives
Recently,
great attention has been paid to developing new drug delivery systems
to manage the rate, time, and site of drug release. We aimed to design a
novel drug delivery system to support targeted and gradual delivery of
levothyroxine sodium.
Materials and methods
The
triblock copolymers of PLA-PEG-PLA and PLGA-PEG-PLGA were constructed
using the ring-opening copolymerization method and then purified and
characterized by 1H-NMR, DSC, and GPC techniques. The phase transition
temperature of the polymers was determined, and levothyroxine sodium
stability was investigated in a phosphate-based buffer (pH 7.4). In
vitro drug release into the PBS was measured at different concentrations
of the triblocks for one month.
Results
The
results of NMR and GPC showed successful fabrication of the copolymers
with low molecular weight dispersion and Tg points of -8.19 °C and -5.19
°C for PLA-PEG-PLA and PLGA-PEG-PLGA, respectively. Stability tests
showed that during one month, most of the triblocks' masses degraded at
37 °C while levothyroxine sodium remained stable. Initial burst release
of the drug in both copolymers is inversely correlated with the
concentration of the polymer. Evaluation of drug release for 35 days
showed that PLA-PEG-PLA had a slower drug release rate than
PLGA-PEG-PLGA.
Conclusion
Considering
the low initial burst release, as well as continuous and long-term
release kinetics of PLA-PEG-PLA and PLGA-PEG-PLGA copolymers, they can
be used to gradually deliver levothyroxine sodium, obviating the need
for frequent administrations and concerns over drug-food interactions.
https://europepmc.org/article/MED/35656181
Transdermal Delivery Systems for Biomolecules.
Purpose
The
present review article focuses on highlighting the main technologies
used as tools that improve the delivery of transdermal biomolecules,
addressing them from the point of view of research in the development of
transdermal systems that use physical and chemical permeation enhancers
and nanocarrier systems or a combination of them.
Results
Transdermal
drug delivery systems have increased in importance since the late 1970s
when their use was approved by the Food and Drug Administration (FDA).
They appeared to be an alternative resource for the administration of
many potent drugs. The first transdermal drug delivery system used for
biomolecules was for the treatment of hormonal disorders. Biomolecules
have been used primarily in many treatments for cancer and diabetes,
vaccines, hormonal disorders, and contraception.
Conclusions
The latest technologies that have used such transdermal biomolecule transporters include electrical methods (physical penetration enhancers), some chemical penetration enhancers and nanocarriers. All of them allow the maintenance of the physical and chemical properties of the main proteins and peptides through these clinical treatments, allowing their efficient storage, transport, and release and ensuring the achievement of their target and better results in the treatment of many diseases.
https://europepmc.org/article/MED/33425065
If any more interesting papers are published, I'll happily add them to this blog if you tell me about them.
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[i][b]helvella - Transdermal Levothyroxine[/b]
Some links and information about the possibility of developing transdermal levothyroxine products.
Last updated 10/02/2025[/i]
Link to blog:
https://helvella.blogspot.com/p/helvella-transdermal-levothyroxine.html
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