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Main Subject - Selecting Wire Guides
One of the criteria in selecting wire guides is the hardness value. Ultra hard materials such as high alumina and tungsten carbide are preferred
According to USFDA, a combination product is one composed of any combination of a drug and device; biological product and device; drug and biological product
over plastics or steel. Figure 1 shows the Vickers hardness of the ultra hard materials that we use and their fracture toughness:
Figure 1
An
Figure 1
An
; or drug, device, and biological product and fixed dose combination would include two or more combinations of drug.
Examples of combination products may in
Examples of combination products may in
ther criterion in selecting wire guides is the surface finish, which attributes to the guides' coefficient of friction against the wire.
Scienti
Scienti
lude drug-coated devices, drugs packaged with delivery devices in medical kits, and drugs and devices packaged separately but intended to be used together.
ic means are employed to ascertain the surface finish in unambiguous numbers. One such instrument is the diamond probe profilometer, which gives
here is enormous increase in the number of combination products entering the market in the recent years. Combination products have proven advantages but fixe
readings in microns or micro inches. One micron is equal to 40 micro inches. A lower profilometer reading generally indicates a smoother surfac
d dose combinations are still in the process of convincing regulatory authority on their advantages over the single ingredient formulations.
Combination pro
Combination pro
finish. An interesting yet little known fact is that higher hardness is always associated with a finer surface finish, while mono-crystalline (
ucts have become life saving products for the pharmaceutical companies who doesn’t have many innovative molecules in their product pipeline and have been inc
hat is, a single crystal) materials like ruby and sapphire finish better compared with polycrystalline materials of the same hardness.
In recent
In recent
easingly used in the product life cycle management. Even the companies having product patents are trying to extend their product life cycle through the combi
years Fracture Toughness, a measure of the resistance of a material to the propagation of a crack, has had an increasing involvement in the inter
nation products and maximize the revenues. But the companies involved in this practice are overlooking that they are burdening the patients both economically
retation of wear phenomena.
It can be seen in Figure 1 that transformation toughened Zirconia (TTZ) and tungsten carbide offer higher fracture t
It can be seen in Figure 1 that transformation toughened Zirconia (TTZ) and tungsten carbide offer higher fracture t
and physically. They need to rightly judge the benefits of the combination products and they have to even look at the risks involved when combining the produ
ughness compared with sapphire and alumina s.
Over the years, extensive tribologial tests have been performed on the ultra hard materials that w
Over the years, extensive tribologial tests have been performed on the ultra hard materials that w
ts. Some of the combination products were well accepted by physicians while others suffered. Companies involved in development of combination products are fi
choose for wire guides.
Synthetic Sapphire from one single source* and of the same lot is chosen as the control and subject to an identical set
Synthetic Sapphire from one single source* and of the same lot is chosen as the control and subject to an identical set
ding difficulty in defining their combination products and facing various challenges from selecting a combination to marketing it.
Following aspects would a
Following aspects would a
of testing parameters. By dividing the unit weight loss of the material under the test by that of the synthetic sapphire, a specific wear rate is
dd to the challenges in developing combination products:
Which markets to tap where the combination products can do fairly well?
Which combination prod
Which markets to tap where the combination products can do fairly well?
Which combination prod
obtained. The specific wear rates obtained so far are tabulated in Figure 2:
Figure 2
It can be seen that among the materials tested, TTZ Zirc
Figure 2
It can be seen that among the materials tested, TTZ Zirc
cts are meaningful and rational?
Which therapeutic categories to select?
Which Combinations can address unmet needs of the patients?
Do combin
Which therapeutic categories to select?
Which Combinations can address unmet needs of the patients?
Do combin
nia, of an inferior hardness but of a higher fractural toughness, outwears synthetic Sapphire. This is also true in the case of tungsten carbide
tions increase the patient compliance?
What would be the developing cost?
How to tackle the risks encountered during combination product developmen
What would be the developing cost?
How to tackle the risks encountered during combination product developmen
All the polycrystalline Alumina s of an inferior hardness and adjacent fracture toughness perform less satisfactorily. The spread in wear resi
t?
As combination products don't fit into the traditional categories of drugs, medical devices, or biological products, the USFDA is in the process of devel
As combination products don't fit into the traditional categories of drugs, medical devices, or biological products, the USFDA is in the process of devel
tance among the alumina s is attributed to the percentage of the alumina content; the compacting pressure of the green body; and the mesh distrib
ping new procedures for reviewing their safety, efficacy and quality.
Professional from academic institutions, pharmaceutical industries, health care indust
Professional from academic institutions, pharmaceutical industries, health care indust
tion (of the powder). It can be postulated at this writing that hardness and toughness should be considered hand in hand when selecting ultra ha
y and representatives from various regulatory agencies are working out to design the regulatory requirements for manufacture and sale of combination products
d materials for wire guides.
It is hoped that with sufficient data and a sound statistical approach, one might someday be able to assign functio
It is hoped that with sufficient data and a sound statistical approach, one might someday be able to assign functio
.
As there is an increasing trend of the combination products companies manufacturing such products should be able to tackle the problems involved in the de
As there is an increasing trend of the combination products companies manufacturing such products should be able to tackle the problems involved in the de
al factors to each of the hardness and toughness plus other relevant values yet to be identified - that is, a mathematical model - in predicting
elopment. They need to be wiser in analyzing the market trends and the regulatory requirements.
Companies that provide selfless information through particip
Companies that provide selfless information through particip
he wear resistance of ultra hard materials without going through the elaborate wear tests.
*Hrand Djevahirdjian S. A. Switzerland (www.djeva.com
*Hrand Djevahirdjian S. A. Switzerland (www.djeva.com
tion in industry events and feedback to regulatory authorities would be able to face the challenges and will be successful in developing combination products
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