<PAGE>
 
                                                                   Exhibit 10.30

                               SECURITY AGREEMENT
                               ------------------

     This Security Agreement (the "Agreement") is entered into as of the 13th
day of January, 1997, by and between Jayhawk Medical Acceptance Corporation, a
Texas corporation (herein referred to as "Debtor"), and Carl H. Westcott (herein
referred to as "Secured Party").

                            Introductory Provisions:
                            ----------------------- 

     The following provisions are true and correct and are a part of this
Agreement:

     A.   Debtor has executed a Promissory Note dated October 1, 1996, payable
to the order of NationsBank of Texas, N.A. (the "Bank") in the face amount of
$15,000,000 (the "Note").

     B.   Secured Party has executed a Continuing and Unconditional Guaranty
dated October 1, 1996, in favor of Bank (the "Guaranty"), pursuant to which
Secured Party guaranteed the payment when due of all indebtedness of Debtor to
Bank, including, without limitation, the obligations of Debtor to Bank under the
Note.

     C.   The execution of this Agreement by Debtor is a condition to Secured
Party guaranteeing future advances by Bank under the Note or otherwise.

     D.   In order to secure the payment by Debtor of the Obligations (as herein
defined below), Debtor desires to grant a security interest in and to certain
property of Debtor to Secured Party pursuant to the terms and conditions hereof.

     NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged and confessed, the parties hereto agree as follows:

     1.   CERTAIN DEFINITIONS.  Unless otherwise defined herein, or the context
          -------------------                                                  
hereof otherwise requires, each term defined in the Uniform Commercial Code of
the State of Texas (the "Code") is used in this agreement with the same meaning;
provided that if any definition given a term in Chapter 9 of the Code conflicts
-------- ----                                                                  
with the definition given that term in any other chapter of the Code, the
Chapter 9 definition shall prevail.

     2.   SECURITY INTEREST AND COLLATERAL.  Debtor hereby grants to Secured
          --------------------------------                                  
Party a security interest in the following property (all of the following being
herein sometimes referred to as the "Collateral"):

     a.   Whether now owned or hereafter acquired by Debtor, wherever located,
          all present and future accounts, general intangibles, chattel paper,
          documents, instruments, inventory, equipment, fixtures, other goods,
          minerals, money, installment contracts, and deposit accounts.
<PAGE>
 
     b.   The balance of every deposit account of Debtor and any claim of Debtor
          against Secured Party, now or hereafter existing, whether liquidated
          or unliquidated.

     c.   All present and future increases, profits, combinations,
          reclassifications, improvements, and products of, accessions,
          attachments, and other additions to, tools, parts, and equipment used
          in connection with, and substitutes and replacements for, all or part
          of the Collateral heretofore described.

     d.   All present and future accounts, general intangibles, chattel paper,
          documents, instruments, cash and noncash proceeds, and other rights
          arising from or by virtue of, or from the voluntary or involuntary
          sale or other disposition of, or collections with respect to, or
          insurance proceeds payable with respect to, or proceeds payable by
          virtue of warranty or other claims against manufacturers of, or claims
          against any other person or entity with respect to, all or any part of
          the Collateral heretofore described in this subparagraph or otherwise.

     e.   All present and future security for the payment to Debtor of any of
          the Collateral heretofore described and goods which gave or will give
          rise to any of such Collateral or are evidenced, identified, or
          represented therein or thereby; provided that the description of
                                          -------- ---- 
          Collateral contained in this Paragraph 2(e) shall not be deemed to  
                                       --------------
          permit any action prohibited by this agreement or by terms
          incorporated in this agreement.

     3.   THE OBLIGATION.  The security interest herein granted shall secure 
          --------------   
full payment and performance of any claim, right or remedy which Secured Party
may now have or hereafter acquire against Debtor that arises under the Guaranty
and/or from the performance by Secured Party thereunder including, without
limitation, any claim, remedy or right of subrogation, reimbursement,
exoneration, contribution, indemnification, or participation in any claim, right
or remedy of Bank against Debtor or against any security which Bank now has or
hereafter acquires, whether or not such claim arises in equity, under contract,
by statute, under common law or otherwise (the "Obligation").

     4.   REPRESENTATIONS AND WARRANTIES OF DEBTOR.  Debtor represents and
          ----------------------------------------                        
warrants that: (a) Debtor is the owner of the Collateral; (b) Debtor has
authority to execute and deliver this Agreement; (c) no financing statement or
amendment or renewal of any financing statement covering the Collateral, or any
part thereof, has been filed and not fully released or completely expired,
except any financing statement showing Secured Party as the sole secured party
thereon; (d) no security agreement covering the Collateral, or any part thereof,
has been made and not fully released, except any security agreement with regard
to which Secured Party is the sole secured party; (e) no security interest in or
encumbrance on the Collateral, or any part thereof, exists, except any security
interest or encumbrance in favor of Secured Party; and (f) no dispute, right of
setoff, counterclaim, or defense exists with respect to all or any part of the
Collateral.

     5.   COVENANTS OF DEBTOR.  So long as any part of the Obligation remains
          -------------------                                                
unpaid or unperformed, Debtor covenants and agrees to: (a) use the Collateral
with reasonable care, skill, and caution; (b) keep the tangible Collateral in
good repair, working order and condition, and promptly make all necessary
repairs and replacements to that end; (c) keep the Collateral properly
sheltered, and prevent the same from becoming damaged, injured, or depreciated;
(d) pay, before delinquent, all taxes and other assessments lawfully levied
against all or any of the Collateral; (e) keep the Collateral fully insured in
such amounts, 

                                       2
<PAGE>
 
against such risks, and with such insurers as may be satisfactory to Secured
Party, and at any time, at the request of Secured Party, furnish to Secured
Party satisfactory proof of maintenance of such insurance and the payment of
premiums thereon, and, if requested by Secured Party, deposit with the latter
the policies or certificates evidencing such insurance, provided that in the
event of a breach by Debtor of any of the provisions of this clause, Secured
Party may at its option maintain insurance on only Secured Party's interest in
the Collateral, any cost incurred thereby by Secured Party to be part of the
Obligation; (f) from time to time, and at any time, promptly execute and deliver
to Secured Party all other assignments, certificates, supplemental documents,
and financing statements, and do all other acts or things as Secured Party may
reasonably request in order to more fully evidence and perfect the security
interest herein created; (g) punctually and properly perform all of the
covenants, duties, obligations and liabilities of Debtor under the Note, and any
other agreement now or hereafter existing as security for or in connection with
the payment and performance of the Obligation or the Note, or any part thereof;
(h) promptly furnish such information as Secured Party may reasonably request
concerning the Collateral; (i) allow Secured Party to inspect the Collateral and
all records of any of Debtor relating thereto or to the Obligation, and to make
and take away copies of such records; (j) promptly notify Secured Party of any
change in any fact or circumstance warranted or represented by Debtor herein, or
in any other document furnished to Secured Party in connection with the
Collateral or the Obligation; (k) promptly notify Secured Party of any claim,
action, or proceeding affecting title to the Collateral, or any part thereof, or
the security interest herein created and, at the request of Secured Party,
appear in and defend, at Debtor's expense, any such action or proceeding; (l)
promptly, after being requested by Secured Party, pay to Secured Party the
amount of all reasonable expenses, reasonable attorneys' fees and other legal
expenses incurred by Secured Party in enforcing the Obligation and the security
interest herein created; (m) not, without the prior written consent of Secured
Party, lease, sell, assign, furnish under any contract of service, transfer,
abandon, or otherwise dispose of the Collateral; (n) not, without the prior
written consent of Secured Party, create any security interest in, mortgage, or
otherwise encumber the Collateral, or any part thereof, or permit the same to be
or become subject to any lien, attachment, execution, sequestration, or other
legal or equitable process, or any encumbrance of any kind or character, except
any solely in favor of Secured Party; (o) not use the Collateral, or permit the
same to be used, for any unlawful purpose or in any manner inconsistent with the
provisions or requirements of any insurance policy required hereunder; and (p)
not move or allow the Collateral, or any part thereof, to be moved across any
state boundary before (i) notice describing the current location, the proposed
removal and the proposed new location is given to and received by Secured Party
seven days in advance of a proposed removal and (ii) written consent of Secured
Party to the removal of such Collateral in such manner and to such location is
received by Debtor.

     6.   DEFAULT. The occurrence of any of the following events shall at the
          -------                                                            
option of Secured Party (or automatically upon the occurrence of an event
described in clause (f) below of this Section 6)  constitute an event of default
                                      ---------                                 
(an "Event of Default") under this Agreement:  (a) the failure to timely pay or
     ----------------                                                          
perform any obligations contained in the Note; (b) the failure or refusal of
Debtor to timely pay the Obligation, or any part thereof; (c) the occurrence of
an event of default under that certain Agreement dated October 1, 1996, by and
between Debtor and Bank; (d) any representation or warranty made by Debtor (or
any of its officers) under or in connection with this Agreement which shall
prove to have been incorrect in any material respect when made, or any failure
by Debtor to perform or observe any term, covenant or agreement contained in
this Agreement on its part to be performed or observed, which default or
nonperformance remains unremedied for a period of five (5) days after Debtor
receives notice thereof from Secured Party; or (f) Debtor shall (I) become
insolvent within the meaning of the Bankruptcy Code of the United States, as
amended, (II) admit in writing its or his inability to pay or otherwise fail to
pay its or his debts generally as they become due, or (III) suffer the
appointment of a receiver, trustee, custodian or similar 

                                       3
<PAGE>
 
fiduciary, or shall make an assignment for the benefit of creditors, or any
petition for an order for relief shall be filed by or against Debtor under the
Bankruptcy Code (if against Debtor, the continuation of such proceeding for more
than 30 days), or Debtor shall make any offer of settlement, extension or
composition to their respective unsecured creditors generally.

     7.   REMEDIES.  Upon the occurrence of a Default, in addition to any and 
          --------        
all other rights and remedies which Secured Party may then have hereunder, under
the Code or otherwise, Secured Party at its option may: (a) enter upon the
premises where any of the Collateral is located and take possession thereof and
remove the same, with or without judicial process; (b) reduce its claim to
judgment, foreclose or otherwise enforce its security interest in all or any
part of the Collateral by any available judicial procedure; (c) after
notification, if any, provided for in Paragraph 8 hereof, sell, lease, or
                                      -----------                        
otherwise dispose of, at the office of Secured Party, on the premises of Debtor
or elsewhere, as chosen by Secured Party, all or any part of the Collateral, in
its then condition or following any commercially reasonable preparation or
processing, and any such sale or other disposition may be as a unit or in
parcels, by public or private proceedings, and by way of one or more contracts
(it being agreed that the sale of any part of the Collateral shall not exhaust
Secured Party's power of sale, but sales may be made from time to time, and at
any time, until all of the Collateral has been sold or until the Obligation has
been paid or performed in full), and at any such sale it shall not be necessary
to exhibit the Collateral; (d) at Secured Party's discretion, surrender any
policies of insurance on the Collateral and receive and apply the unearned
premiums as a credit on the Obligation, and, in connection therewith, Debtor
hereby appoints Secured Party as the agent and attorney-in-fact for Debtor to
collect such premiums, Secured Party to exercise such power at its sole
discretion; (e) at Secured Party's discretion, retain the Collateral in
satisfaction of the Obligation whenever the circumstances are such that Secured
Party is entitled to do so under the Code; (f) apply the proceeds of any sale or
other disposition of the Collateral in the following order: first, to the
payment of all of its reasonable expenses (including, but not limited to, the
cost of any insurance, payment of taxes or other charges, and reasonable
attorneys' fees and other legal expenses) incurred in retaking, holding,
operating, preparing and preserving the Collateral or any part thereof for
sale(s) or other disposition, in arranging for such sale(s) or other
disposition, and in actually selling the same; next, to the payment of the
balance of the Obligation in such order and manner as Secured Party, in its
discretion, may deem advisable; and last, Secured Party shall account to Debtor
for any surplus, payment of which surplus to Debtor shall discharge Secured
Party with regard to Debtor; provided that Secured Party shall not be required
to account to Debtor for, and shall be entitled to retain, all such surplus, if
any, until such time as all of the Obligation shall have been discharged in full
and no part of the Obligation, whether matured or to arise in the future, shall
remain undischarged; and (g) exercise any and all other rights, remedies and
privileges it may have hereunder or under the Guaranty.

     8.   NOTICE OF SALE.  Reasonable notification of the time and place of any
          --------------                                                       
public sale of the Collateral, or reasonable notification of the time after
which any private sale or other intended disposition of the Collateral is to be
made, shall be sent to Debtor and to any other person entitled under the Code to
notice; provided, that if the Collateral is perishable, threatens to decline
speedily in value, or is of a type customarily sold on a recognized market,
Secured Party may sell or otherwise dispose of the Collateral without
notification, advertisement, or other notice of any kind.  It is agreed that
notice sent or given not less than ten calendar days prior to the taking of the
action to which the notice relates, is reasonable notification and notice for
the purposes of this paragraph.

     9.   MISCELLANEOUS.
          ------------- 

                                       4
<PAGE>
 
     (a)  Should any part of the Collateral come into the possession of Secured
Party, whether before or after Default, Secured Party may use or operate the
Collateral for the purpose of preserving it or its value or pursuant to the
order of a court of appropriate jurisdiction, or in accordance with any other
rights held by Secured Party in respect of the Collateral.  Debtor covenants to
promptly reimburse and pay to Secured Party, at Secured Party's request, the
amount of all reasonable expenses (including, but not limited to, the cost of
any insurance, payment of taxes or other charges and reasonable attorney's fees
and other legal expenses) incurred by Secured Party in connection with its
custody, preservation, use or operation of the Collateral, and, all such
expenses, costs, taxes and other charges shall be a part of the Obligation and
shall bear interest at the highest lawful rate from the date incurred until the
date repaid to Secured Party.  It is agreed, however, that the risk of loss or
damage to the Collateral is on Debtor, and Secured Party shall have no liability
whatever for failure to obtain or maintain insurance or for failure to determine
whether any insurance ever in force is adequate as to the amount or as to risks
insured.

     (b)  Secured Party shall have the right at any time to execute and file
this Agreement as a financing statement, but the failure of Secured Party to do
so shall not impair the validity or enforceability of this Agreement.

     (c)  All rights and remedies of Secured Party hereunder are cumulative of
each other and of every other right or remedy which Secured Party may otherwise
have at law or in equity or under any other contract or document for the
enforcement of the security interest herein or the collection of, or enforcement
of the security interest herein or the collection of, or enforcement of the
performance of, the Obligation, and the exercise of one or more rights or
remedies shall not prejudice or impair the concurrent or subsequent exercise of
other rights or remedies or a further or other exercise of the same right or
remedy.

     (d)  Debtor shall not be permitted to take or fail to take any action which
is permitted as an exception to any of the covenants contained herein or which
is within the permissible limits of any of the covenants contained herein if
such action or omission would result in the breach of any other covenant
contained herein.

     (e)  Whenever herein the singular number is used, the same shall include
the plural where appropriate, and words of any gender shall include each other
gender where appropriate.

     (f)  All notices, demands, requests and other communications required or
permitted hereunder must be in writing to be effective and shall be deemed to
have been given when actually received, or if earlier and regardless of whether
actually received (except where receipt is specified herein), upon deposit in a
regularly maintained receptacle for the United States mail, registered or
certified, postage prepaid, addressed to the addressee at its address set forth
below (provided that nothing in this subparagraph shall extend the notice period
set out in Paragraph 8 hereof):
           -----------         

               Debtor:             Jayhawk Medical Acceptance Corporation
                                   Two Galleria Tower, Suite 1800
                                   13455 Noel Road
                                   Dallas, Texas 75240

                                       5
<PAGE>
 
               Secured Party:        Carl H. Westcott
                                     100 Crescent Court
                                     Suite 1620
                                     Dallas, Texas 75201

or to such other address as any party hereto shall hereafter designate by
written notice delivered in accordance with this subsection and actually
received by the addressed party.

     (g)  This Agreement is being executed and delivered in, and is intended to
be performed in, the State of Texas, and the laws of the State of Texas shall
govern the validity, construction, enforcement, and interpretation of this
Agreement.

     (h)  If any provision of this Agreement is held to be illegal, invalid, or
unenforceable under present or future laws effective during the term of this
Agreement, the legality, validity, and enforceability of the remaining
provisions of this Agreement shall not be affected thereby, and in lieu of each
such illegal, invalid, or unenforceable provision there shall be added
automatically as a part of this Agreement a provision as similar in terms to
such illegal, invalid, or unenforceable provision as may be possible and be
legal, valid, and enforceable.

     (i)  With respect to any of the Collateral which is or becomes accounts,
instruments or chattel paper, Secured Party, without notice to Debtor, shall be
entitled, but not obligated, at any time and from time to time, to notify and
direct the  account debtor or obligor thereon to thereafter make all payments on
such Collateral directly to Secured Party, regardless of whether Debtor was
previously making collections thereon. Each account debtor and obligor making
payment to Secured Party hereunder shall be fully protected in relying on the
written statement of Secured Party that it then holds the security interest(s)
which entitle it to receive such payment, and the receipt of Secured Party for
such payment shall be full acquittance therefor to the one making such payment.

     (j)  This Agreement has been executed in a number of identical
counterparts, each of which, for all purposes, is to be deemed an original, and
all of which collectively constitute one agreement, but in making proof of this
Agreement, it shall not be necessary to produce or account for more than one
such counterpart.

     (k)  All covenants, agreements, undertakings, representations and
warranties made herein shall survive all closings hereunder unless and except as
otherwise indicated, and shall not be affected by any investigation made by any
party.

     (l)  This Agreement shall be binding upon and inure to the benefit of
Debtor, its successors and permitted assigns, and shall insure to the benefit of
Secured Party and its successors and assigns.

                                       6
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed in multiple original counterparts as of the day, month and year
first above written.

                             DEBTOR:
    
                             JAYHAWK MEDICAL ACCEPTANCE CORPORATION
    
    
                             By:      /s/ FRED JACKSON
                                ----------------------------------------------
                             Title:        Chief Financial Officer
                                   -------------------------------------------
    
    
                             SECURED PARTY:
    
    
                               /s/ CARL H. WESTCOTT
                             -------------------------------------------------
                             CARL H. WESTCOTT

                                       7