Title of Invention

PRODUCTION OF FINE GRADE ABSORBABLE SURGICAL SUTURES FROM FISH GUT COLLAGEN

Abstract

A process for producing fine grade absorbable surgical suture comprising of extraction of gut from the fresh water fishes Labeo Rohita, Cirrhinus mrigala and Catla catla, cleaning the gut by axial flow of water, removal of all soluble proteins by a mixture of 0.01 N sulphuric acid and 10% salt to give pure collage filaments, twisting, cross-linking and strengthening filaments by soaking in a bath of 0.02 % chromium trihydroxide, 10%-15% sodium chloride and 1 ppm ferric hydroxide followed by coating with 30 % alcoholic suspension of 1% gelatin or collagen and drying the product as fine absorbable surgical suture for surgical procedures.

Full Text

3. Description This invention relates to the field of medical sciences. In particular this invention relates to surgical sutures. Especially this invention relates to fine grade absorbable surgical sutures from collagen obtained from the gut of fish. The aim of this invention is to prepare fine grade absorbable surgical sutures from fish gut collagen, for suturing surgical wounds of various types in human beings. This present invention makes use of purified collagen filaments from fish, sulphuric acid, sodium chloride, sodium dichromate, sodium bicarbonate, starch and collagen suspension from fish maws to prepare fine grade absorbable surgical surture. The success of fine grade absorbable surture lies in the strengthening of the fish gut collagen filaments in such a way that the resulting surture has sufficient knot pull strength or tenacity and is not absorbed at least for 10 to 15 days, by which time the wound heals naturally and the surture gets absorbed within 30 days. The primary object of the invention is to develop a low cost indigenous technology for production of absorbable surgical sutures. Another object of the invention is to develop more tissue compatible absorbable sutures. Further object of this invention is to utilize cheap and indigenous raw material. Further object of this invention is to bring down cost of absorbable surgical sutures. Further object of this invention is to increase the supply and avoid scarcity of the absorbable surgical sutures in Indian market. Existing Technology for Production of absorbable surgical sutures (catgut) The existing production technology for absorbable surgical sutures (catgut) involves purification of the collagen filaments of submucosa of the intestines of land animals like cattle, sheep, goat etc. The purified submucosa of animals is partially dried and twisted to give long threads. These threads are further dried and sterilized to give plain catgut. The plain catgut (absorbable surgical sutures) have only a short tissue life of 4 to 5 days. For certain surgeries where tissue heals in 3 to 4 days such plain catgut is used for suturing. But in most surgical cases the healing time is 7 to 8 days, so the plain catgut will not be effective. For suturing such wounds catgut with a longer tissue life is required. This is achieved by tanning the plain catgut with certain chemicals, normally chromium salts. Such absorbable surgical sutures , are called chromicised sutures (chromisiced catgut) and they will be absorbed in tissue only after 10 to 12 days by which time almost all the wounds will be healing. The advantages of this technology are: 1. It enables the natural absorption of sutures after the wound heals (After 10 to 12 days) 2. Strong and thicker grades of sutures can be easily prepared 3. Tissue reactions are comparatively less when compared with the synthetic absorbable sutures The Disadvantages of this are: 1. Thinner grades of sutures (9-0 to 4-0) cannot be prepared. 2. The knot pull strength, which is an important property of surgical sutures, is less for thinner grades of catgut prepared from cattle, sheep and goat intestines. 3. Some tissues reactions for catgut prepared from the intestines of cattle, sheep and goat is common. 4. Catgut of thinner grades suitable for microsurgeries and cosmetic surgeries cannot be prepared. The main difference of new technology from existing technology 1. The raw material for the new technology is the intestines of certain fishes like rohu? catla and mrigal which are largely herbivorous fishes. 2. The production technology involves physical cleaning of guts by axial flow of water, dissolution and removal of non collagen proteins by pickling, followed by twisting, cross linking and strengthening of collagen threads by chromium trihydraoxide and ferric hydroxide treatment, washing in potable water, drying, polishing, packing and sterilization with ethylene oxide/UV. Advantages of new technology 1. The fine grade absorbable sutures(7-0 to 1-0) can be prepared easily. 2. The cost of production is considerably less(about Rs. 5/- per suture). 3. The suture prepared by the new technology is almost free from tissue reactions. 4. With the new technology production of suitable catgut for micro surgery and cosmetic surgery will be easy and cheap. 5. Being soft, tissue cutting effect of these fine grade catguts is minimum compared to synthetic absorbable and nonabsorbable sutures of similar grade. 6. Availability and scope for preparation catgut (absorbable surgical sutures ) in the size grades ranging from 7-0 to 1-0, which are common requirements of cosmetic, micro, ophthalmic and major surgeries. 7. Most of the fine grade sutures in the range 9-0 to 4-0 are imported and monopoly products of M/s. Ethicon. So the present technology offers scope for indigenous production of fine grade absorbable surgical sutures, with scope for export. 8. The raw material being herbivorous fish collagen- an early species in evolution chances of rejection and allergic reactions are minimum. Studies have proved this. 9. This is tirst time in the world absorbable surgical sutures are prepared from fish gut collagen Now the invention will be described in detail with reference to the drawings accompanying this specification, shown as Figure-1 indicating in block diagram various steps involved in the process of manufacturing fine grade absorbable surgical sutures from fish gut collagen. The gut of fresh fish is extracted and cleaned by axial flow of water in a gut cleaning system fabricated for the purpose. This is shown as step 1 in figure 1. The cleaned guts are then extracted with solution of dilute sulphuric acid (0.01 N) in brine (10%) to give collagen filaments with necessary stability. This step is known as pickling which is shown as process step No.2 in the block diagram (fig 1). The collagen filaments are then twisted so as to impart physical strength to the collagen filaments. Further a step of cross-linking is effected so as to impart physical strength to collagen filaments. Thereafter the collagen filaments are mounted on a frame and soaked in a solution containing 0.02% chromium trihydroxide, lppm Ferric Hydroxide and 10-15% sodium chloride at 40 degree Centigrade for 6 hours. These processes of twisting, Cross-linking & thickening, neutralization and washing are shown at steps No 3, 4 & 5 of the said process as in fig 1. The strengthening and neutralization operations are done either in a suture strengthening equipment consisting of a tank for a bath and a revolving frame for mounting the stretched collagen filaments or manually using a dipping tank and circular spindle. The strengthened and neutralized collagen filaments are then coated with 1% collagen suspension in 30% ethanol by repeated dipping and drying using a coating and drying system. This is shown as step No. 6 of the process. The Strengthened and coated sutures are taken out, the frame cut to size graded according to diameter and packed in asceptic condition in concentrated isopropyl alcohol. The Packed sutures are sterilized by UV irradiation or ethylene oxide to give fine grade absorbable surgical suture for use as suture material. The process of grading and polishing is shown as step No 7 of the process and the steps of packing, sterilization and final storage are shown as steps no 8, 9 and lastly 10 of the process in fig 1. When commercialized, the hitherto wasted portions of fish, like fish guts will fetch a good price. Thereby ensuring a better return to the fishermen. It will also help in reducing environmental pollution caused by the unhygienic and improper disposal of presently unutilized fish viscera. Sutures below 3-0 grade are often imported to meet internal demand. Under this situation the process developed will also help import substitution if the same is used for commercial production. ii. The product prepared from the purified collagen filaments from the guts of any species of the fishes Labeo rohita, cirrhinus mmrigala and catla catla, after twisting, chromising and smoothening for use as absorbable suture in surgical operations. 1/ We Claim (1) A Process for producing fine grade absorbable surgical suture comprising of extraction of gut from the fresh water fishes Labeo rohita, Cirrhinus mrigala and Catla Catla, cleaning the gut by axial flow of water, removal of all soluble proteins by a mixture of 0.01 N Sulphuric acid and 10% salt to give pure collegen filaments, twisting, cross linking and strengthening filaments by soaking in a bath of 0.02% chromium trihydroxide 10%-15% sodium chloride and 1 ppm ferric hydroxide followed by coating with 30% alcoholic suspension of 1% gelatin or collagen and drying the product as fine absorbable surgical suture for surgical procedures. (2) A product prepared from the purified collagen filaments from the guts of any species of the fishes Labeo rohita, cirrhinus mrigala and catla catla, after twisting, chromising and smoothening for use as absorbable suture in surgical operations.

Documents:

790-mas-2000-abstract.pdf

790-mas-2000-claims filed.pdf

790-mas-2000-claims granted.pdf

790-mas-2000-correspondnece-others.pdf

790-mas-2000-correspondnece-po.pdf

790-mas-2000-description(complete) filed.pdf

790-mas-2000-description(complete) granted.pdf

790-mas-2000-drawings.pdf

790-mas-2000-form 1.pdf

790-mas-2000-form 3.pdf

790-mas-2000-other documents.pdf