Patent Description:
Type II Diabetes Mellitus is the most common type of diabetes worldwide. It is associated with increased blood glucose and contributes to a high rate of cardiovascular morbidity and mortality. While the cornerstone therapy to treating Type II Diabetes is weight loss, regular exercise and diet, antidiabetic drugs are used to maintain blood sugar. Type II Diabetes Mellitus is treated with oral hypoglycemics (sulfonylureas, biguanides, α-glucosidase inhibitors, meglitinide analogues and thiazolidinediones). The conventional dosage forms of oral hypoglycemics are challenged due to the need for frequent dosing, shortened half live and low bioavailability. There are significant complications and side effects posed by parenteral drugs or oral route of delivery, including invasive drug delivery systems; gastrointestinal bowel irritation due to interaction of the drug with other intestinal substances; drug reduction due to extensive first pass metabolism and toxicity; toxicity and poor aqueous solubility.

Advances have been made to improve drug delivery and to alleviate these challenges. These advances include drug delivery systems that deliver drugs at a constant rate and sustained release, reduced side effects and frequent doses. These drug delivery systems include microspheres, nanosystems, hydrogels, transdermal delivery systems, niosomes and controlled release tablets. Patent document <CIT> discloses oil-in-water nanoemulsions comprising diosgenin suitable for transdermal delivery of diosgenin to a patient to treat type II diabetes mellitus.

The invention addresses these problems arising from the use of parenteral drugs or oral route of delivery by providing a non-invasive and naturally formulated transdermal delivery system for a phytoactive antidiabetic agent - diosgenin. Diosgenin is a natural steroidal sapogenin that is extracted from herbs including Dioscorea rhizome, Dioscorea villosa, Trigonella foenum-graecum, Smilax China, and Rhizoma polgonati. It is used in the treatment of various diseases and medical conditions including cancers, hyperlipidemia, inflammation, infections and diabetes. In the treatment of diabetes, diosgenin has been shown to be effective in regulating the targets and pathways of glycolipid metabolism, apoptosis, inflammation and oxidative stress. To ensure targeted and sustained delivery of diosgenin, the invention discloses a formulation including a nanoemulsion matrix that engulfs and protects diosgenin until it systemically reaches its target.

The invention discloses a nanoemulsified formulation according to the claims that comprises:.

The formulation is therefore a naturally formulated nanoemulsified system. This allows it to permeate the skin to deeply penetrate and cross all barriers to enter the systemic circulation in a controlled manner. The nanoemulsion is prepared using low energy and ambient temperature which is beneficial for its cost effectiveness, ease of accessibility and ability to protect the efficacy of a drug throughout the preparation process by preventing the decomposition of thermolabile active ingredients since little or no temperature is required and instead, it is shown that it is sufficient to use a simple magnetic stirring.

The formulation allows for ease of administration and patient accessibility. It is a non-invasive mode of delivering diosgenin and is pain-free to the patient. It is shown that the solubility of diosgenin is enhanced when dissolved in combination with bottle gourd seed. Nanoemulsion based carriers are the most suitable delivery systems for poorly soluble drugs by improving the drug's solubility, improving permeation of drugs and ultimately increasing bioavailability by transdermal therapeutic systems.

The formulation can be used to treat diabetes, including Type I diabetes, Type II diabetes, gestational diabetes, maturity onset diabetes, neonatal diabetes, Wolfram syndrome, Alström syndrome and latent autoimmune diabetes. It particular, it is used to treat Type II Diabetes Mellitus by either producing the formulation as a cosmetic or gel for transdermal application, or by producing the formulation as a transdermal patch.

According to a first aspect of the invention there is provided a formulation according to the claims comprising an oil-in-water nanoemulsion matrix encapsulating diosgenin which may be dissolved in an oil phase.

The oil phase may comprise an oil selected from at least one of sesame oil, bottle gourd seed oil, flaxseed oil, omega-<NUM> polyunsaturated fish oil, omega-<NUM> polyunsaturated fish oil, safflower oil, olive oil, pine nut oil, cherry kernel oil, soybean oil, pumpkin oil, pomegranate oil, primrose oil, or a combination thereof.

According to the claims, the oil phase comprises a <NUM>:<NUM> mixture of sesame oil and bottle gourd seed oil (Lagenaria sphaerica).

The nanoemulsion matrix may include a non-ionic surfactant and a co-surfactant as emulsifiers.

The non-ionic surfactant may be Tween <NUM> and the co-surfactant may be glycerol.

The ratio of the oil to water is <NUM>:<NUM>.

The formulation may be in the form of a cosmetic, gel, transdermal patch, or similar.

According to a second aspect of the invention there is provided a method according to the claims of producing a formulation comprising a nanoemulsion matrix surrounding diosgenin, wherein the method includes the steps of:.

The oil phase is prepared by combining sesame oil and bottle gourd seed oil in a <NUM>:<NUM> ratio.

The ratio of oil to water is <NUM>:<NUM>.

The nanoemulsion matrix is prepared under low energy using a magnetic stirrer and ambient temperature.

The distilled water is added dropwise to the mixture while stirring by the magnetic stirrer.

The nanoemulsion matrix may be formed into a nanoemulsified gel. Disclosed, but not claimed, is a formulation comprising a nanoemulsion matrix and diosgenin for use in a method of treating diabetes in a patient, wherein the formulation is for transdermal delivery of diosgenin.

The diabetes may be selected from Type I diabetes, Type II diabetes, gestational diabetes, maturity onset diabetes, neonatal diabetes, Wolfram syndrome, Alström syndrome and latent autoimmune diabetes. It particular, the diabetes may be Type II diabetes mellitus. The formulation may be produced according to the method of the second aspect of the invention.

Disclosed, but not claimed, is a use of diosgenin and a nanoemulsion matrix in the manufacture of a formulation for treatment of diabetes in a patient, wherein the formulation is for transdermal delivery of diosgenin.

The diabetes may be any one of Type I diabetes, Type II diabetes, gestational diabetes, maturity onset diabetes, neonatal diabetes, Wolfram syndrome, Alström syndrome and latent autoimmune diabetes. The diabetes may be Type II diabetes mellitus.

The formulation may be produced according to the method of the second aspect of the invention.

The invention will now be described in more detail with reference to the Example hereunder, and the accompanying drawings.

In preparing the formulation, the concentration of diosgenin was measured based on the weight of rats. In view of its hydrophobic nature which limits its solubility in water, diosgenin was incorporated in the oil phase before the emulsification process.

A mixture of <NUM>:<NUM> sesame oil and bottle gourd seed oil (Lagenaria sphaerica) was prepared as the oil phase. Other oils may be used, such as flaxseed oil, omega-<NUM> polyunsaturated fish oil, omega-<NUM> polyunsaturated fish oil, safflower oil, olive oil, pine nut oil, cherry kernel oil, soybean oil, pumpkin oil, pomegranate oil, primrose oil, or a combination thereof.

<NUM> % of an equal mixture of Tween <NUM> and glycerol was added to <NUM>% of the oil phase.

The formulation was produced through a low energy-phase inversion composition technique with less shearing energy. The shearing procedure was conducted at an ambient temperature all through the preparation.

<NUM>/kg body weight (bw) diosgenin was dissolved in the oil phase and stirred at <NUM> rpm using the magnetic stirring hot plate.

Distilled water was titrated dropwise into the oil phase mixture until a phase inversion into an oil-in-water nanoemulsion was obtained with a <NUM> % water content.

Optimized nanoemulsion was modified into a nanoemulsified gel for improved skin applicability.

Prior to treatment, albino Wistar rats were treated with streptozotocin (STZ) to induce Type II Diabetes Mellitus (T2DM). The development and progression of the rats into a diabetic state was confirmed by spectrometrically measuring the random blood glucose level of rats at specific intervals. Rats with a sustained blood glucose level beyond <NUM>/dL and an HbA1c level ≥ <NUM>% were considered hyperglycemic/diabetic.

Diabetic rats were prepared for transdermal treatment with the formulated diosgenin-in-nanoemulsion. <NUM> of <NUM>/kg body weight (bw) diosgenin was applied at every single application <NUM> hourly for a period of three weeks. The therapeutic potential of diosgenin against T2DM was determined by measuring the blood glucose concentration (mg/dL) and HbA1c (%) of treated rats at specific intervals.

Effect of streptozotocin on the blood glucose concentration, glycosylated hemoglobin and HbA1c level in albino Wistar rats.

Table <NUM> presents the results of how the metabolism of normal albino rats progresses into a hyperglycemic/diabetic state as a multiple low-dosage of streptozotocin is administered for diabetes induction.

In <FIG>, the significance of the blood glucose concentration is indicated as * p<<NUM>, ** p<<NUM> and ***p<<NUM> when normal control, NC (n=<NUM>), is compared to disease group, DS (n=<NUM>) at stage <NUM> and <NUM> (DS-<NUM> and DS-<NUM>). # p<<NUM>, ## p<<NUM> and ###p<<NUM> when DS-<NUM> and DS-<NUM> is compared with early intervention and late intervention transdermal treatment (TDEI and TDLI) for three weeks.

In <FIG>, it is evident that the blood glucose concentration in diabetic rats (DS-<NUM> and DS-<NUM>) was highly elevated in comparison to the normal control (NC). With a single week's treatment of the rats using the formulation, the blood glucose concentration decreased significantly, with better results seen at early invention compared to late intervention. The blood glucose concentration for both early and late intervention cases decreased in week <NUM>. In the early intervention cases, there was not a significant decrease in blood glucose concentration in week <NUM> of treatment, but there was a noticeable difference in the late intervention cases in week <NUM>.

In <FIG>, HbA1c levels were measured at the end of disease induction and at the end of the <NUM> week treatment. The significance of each measurement is indicated as * p<<NUM>, ** p<<NUM> and ***p<<NUM> when normal control (NC) is compared to compared to disease stage <NUM> and <NUM> (DS-<NUM> and DS-<NUM>). # p<<NUM>, ## p<<NUM> and ###ρ<<NUM> when DS-<NUM> and DS-<NUM> is compared with early intervention and late intervention transdermal treatment (TDEI and TDLI).

In <FIG>, HbA1c (hemoglobin A1c) levels are highly elevated in diabetic rats (DS-<NUM> and DS-<NUM>) compared to the normal control. With treatment of the rats using the formulation, HbA1c levels decreased significantly, with better results seen at an early invention compared to late intervention. The HbA1c levels in the early intervention cases decreased to below that of the normal control, and in the late intervention cases the HbA1c levels decreased to the same level as the normal control.

Claim 1:
A formulation for transdermal delivery of diosgenin to a patient to treat type II diabetes mellitus in the patient, the formulation comprising diosgenin encapsulated in a nanoemulsion matrix, wherein
the nanoemulsion matrix is an oil-in-water nanoemulsion comprising diosgenin dissolved in an oil phase of the nanoemulsion matrix;
the oil phase comprises a <NUM>:<NUM> combination of sesame oil and bottle gourd seed oil; and
the ratio of oil to water is <NUM>:<NUM>.