<PAGE>   1

                                                                   EXHIBIT 10.23


                                     LEASE

STATE OF OKLAHOMA

COUNTY OF TULSA

THIS LEASE AGREEMENT (this "Lease") is made and entered into this 7th day of
July, 1999, by and between the Landlord and Tenant hereinafter named.


DEFINITIONS AND BANK PROVISIONS

The following definitions and basic provisions shall be consulted in
conjunction with and limited by the references thereto in other provisions of
this Lease:

(a)  "Landlord":                   Twenty First Properties, Inc., an Oklahoma
                                   corporation

(b)  "Landlord's Address":         2121 South Columbia Avenue
                                   Suite 650
                                   Tulsa, Oklahoma 74114-3505

(c)  "Tenant":                     medibuy.com, a Delaware Corporation

(d)  "Tenant's Address":           777 Alvarado Road, Suite 401
                                   La Mesa, California 91941

(e)  "Tenant's Representative":    Charlie Smith

(f)  "Building":                   Atlanta South Office Park

(g)  "Building's Address":         2526 East 71st Street, Suite C
                                   Tulsa, Oklahoma 74136

(h)  "Premises":                   Approximately 1,326 rentable square feet in
                                   the Building, such Premises being shown and
                                   outlined on the plan attached hereto as
                                   Exhibit "A" and being part of the Project
                                   situated on the real property described in
                                   Exhibit "B" attached hereto.

(i)  "Project":                    The term "Project" shall refer to the real
                                   property described in Exhibit "B" together
                                   with Building and all other improvements and
                                   appurtenances thereon, together with any
                                   such additions or changes as Landlord may
                                   from time to time designate as included
                                   within the Project.

(j)  "Environmental Law":          The term "Environmental Law" shall mean any
                                   federal, state, county, municipal, law,
                                   statute, code, rule, ordinance, regulation,
                                   order, judgment, decree, injunction or common
                                   law relating to any Hazardous Substances,
                                   pollution or protection of health and/or the
                                   environment now or at any time hereinafter in
                                   effect, as the same may be amended from time
                                   to time.

(k)  "Total Rentable Square Feet of Building":  81,450

(l)  "Commencement Date":                       August 1, 1999

(m)  "Expiration Date":                         July 31, 2002

(n)  "Term":                                    Three (3) years

(o)  "Rent" or "rent":             Rent or rent as used herein shall be deemed
                                   to consist collectively of (i) base rent as
                                   hereinafter scheduled; and (b) Additional
                                   Rent or additional rent as hereinafter
                                   defined.

(p)  "Schedule of Base Rent":

<TABLE>
<CAPTION>
Months              Monthly Installment           Total Period Base Rent
------              -------------------           ----------------------
<S>                 <C>                           <C>
1-36                $1,270.75                     $45,747.00
-------             --------------------          -----------------------
-------             --------------------          -----------------------
-------             --------------------          -----------------------
-------             --------------------          -----------------------
-------             --------------------          -----------------------
</TABLE>


                                       1
<PAGE>   2
               (q)  "TOTAL SCHEDULED BASE RENT":       $45,747.00

               (r)  "SECURITY DEPOSIT":                $1,270.73

               (s)  "GUARANTOR":                       N/A

                    (EXHIBIT "C" ATTACHED)

               (t)  "PREPAID RENTAL":                  $1,270.75

               (u)  "PERMITTED USES":      General Office Use

                                           -------------------------------------

               (v)  "SPECIAL PROVISIONS":  See Exhibit "A" Tenant Improvements
                                           See Exhibit "B" Rules and Regulations

                                           -------------------------------------

GRANTING
CLAUSE         In consideration of the obligation of Tenant to pay rent as
               herein provided and in consideration of the other terms,
               covenants and conditions hereof, Landlord hereby demises and
               issues to Tenant, and Tenant hereby takes from Landlord, the
               Premises to have and to hold the same for the Term specified
               herein, all upon the terms and conditions set forth in this
               Lease.

SERVICES
BY LANDLORD    Landlord agrees to furnish Tenant during Tenant's occupancy of
               the Premises the following services:

                    (a)  Hot and cold water at those points of supply provided
                         for general use of tenant.

                    (b)  Air conditioning, heat and electric current (for
                         lighting and fractional horsepower machines only)
                         during reasonable hours of generally recognized
                         business days, as determined by Landlord at such
                         quantity and of such quality as Landlord determines in
                         its sole judgement is reasonably necessary for Tenant's
                         comfortable use and enjoyment of the Premises.

                    (c)  Elevator service is common with other tenants for
                         ingress to and egress from the Premises.

                    (d)  Industrial cleaning services, five (5) days per week.

                    (e)  Electrical lighting for public areas and special
                         service areas of the Project in the manner and to the
                         extent deemed by Landlord to be standard.

               Failure to any extent to furnish, or any stoppage of, such
               services, resulting from causes beyond control of Landlord or
               from any cause, shall not render Landlord liable in any respect
               for damages to either person or property, nor be construed as to
               evictions of Tenant or work as abatement of rent, not relieve
               Tenant from fulfillment of any covenant or agreement hereunder.
               Should any equipment or machinery break down, or for any cause
               cease to function properly, Landlord shall use reasonable
               diligence to repair same promptly, but Tenant shall have no claim
               for rebate of rent or damages on account of any interruptions in
               services occasioned thereby or resulting therefrom.

               This Lease is conditioned upon faithful performance by Tenant of
               the following agreements, covenants, rules and regulations,
               herein set out and agreed to by Tenant.

PAYMENTS       (A) All rent payments are due in advance on the first day of each
               and every month, during the Term, and should be payable at the
               place designated for the delivery of notices in Landlord at the
               time of payment, without abatement, deduction setoff,
               courier-claim, suspension, determined or reduction of any kind or
               for any reason. The obligation of Tenant to pay Base Rent is an
               independent covenant, and so act as circumstance whether
               constituting breach of covenant by Landlord or not, shall release
               Tenant of the obligation to pay rent.

               (B) Tenant shall pay as additional rent any sums of money or
               other charges required to be paid by Tenant under this Lease,
               whether or not the same be designated specifically as "additional
               fees".

               (C) Any amount due from tenant to Landlord hereunder which is not
               paid when due shall bear interest at the maximum lawful rate from
               the due date until paid, unless otherwise specifically provided
               herein, but the payment of such interest shall not excuse or cure
               any default by Tenant under this Lease. In addition to such
               interest, if the monthly rental provided herein is not paid
               within five (5) days after the time is due, a late charge equal
               to ten percent (10%) of the amount overdue of One Hundred Dollars
               ($100.00), whichever is greater, which late charge Tenant hereby
               agrees is a reasonable estimate of the damages Landlord shall
               suffer as a result of Tenant's Due payment, which damages include
               Landlord's activities administrative and other costs associated
               with such late payment and the parties agree that it would be
               impracticable or extremely difficult to fix Landlord's actual
               damages in such event. Such interest and late payment penalties
               are separate and cumulative and are in addition to and shall not
               diminish or represent a substitute for any or all of Landlord's
               rights or remedies under any other provision of this Lease.

                                       2









<PAGE>   3
COMMON AREA

2.  The "Common Area" is the part of the Project designated by Landlord from
time to time for the common use of all tenants, including, without limitation,
the parking area, sidewalks, landscaping, curbs, loading areas, private streets
and alleys, lighting facilities, enclosed mall, corridors, hallways, stairs and
public bathrooms, if any, all of which shall be subject to Landlord's sole
management and control and shall be operated and maintained in such manner as
Landlord shall designate. Landlord reserves the right to change from time to
time the dimensions and location of the Common Area, as well as the location,
dimensions, identity and type of any improvements currently a part of, or
planned to be a part of the Project, and to construct additional buildings or
additional stories on existing buildings or other improvements on the Project,
and to eliminate improvements currently a part of the Project. Tenant and its
agents, employees, servants, licensees and invitees shall have the non-exclusive
license to use the Common Area in common with Landlord, other tenants and other
persons permitted by Landlord to use the Common Area subject to the Rules and
Regulations which are attached as Exhibit '3'. Without limiting the foregoing,
Landlord reserves the right to designate parking areas within the Common Area or
in reasonable proximity thereto, for Tenant and Landlord's agents, servants,
employees, contractors, licensees and/or invitees. Tenant shall not solicit
business or display merchandise within the Common Area, or distribute hardbills
therein, or take any action which would interfere with the rights of other
persons to use the Common Area. Landlord may temporarily close the Project (or
part thereof) as a result of disastrous acts of nature, and Landlord shall not
be liable to Tenant for any interruption of Tenant's business during such
periods.


REPAIRS BY TENANT

3.  Tenant will, at Tenant's own cost and expense, keep the Premises and all
other improvements to the extent covered by this Lease in sound condition and
good repair, and shall repair or replace any damage or injury done to the
Premises or any other part of the Project by Tenant or Tenant's agents,
employees, licensees, contractors, invitees and visitors, and if Tenant fails to
make such repair or replacements promptly, or within 15 days of occurrence, to
the satisfaction of Landlord, Landlord may at its option make such repair or
replacement, and Tenant shall pay to Landlord immediately upon demand as
additional rent the costs of such repairs and replacements plus fifteen percent
(15%) of such costs. Tenant will not commit or allow any waste or damage to be
committed on any portion of the Premises, and shall at the expiration or earlier
termination of this Lease by lapse of time or otherwise, deliver up the said
Premises to Landlord in as good condition as at time of possession, ordinary
wear and tear excepted, and upon such termination of this Lease Landlord shall
have the right to re-enter and resume possession of the Premises. Upon move out
by Tenant, should the Premises require any repairs or replacement which are the
responsibility of Tenant hereunder, Landlord shall have the right to make such
repairs or replacements at Tenant's cost and expense.

ASSIGNMENTS OR SUBLETTING

4. Tenant shall not sell, mortgage, transfer, or assign this Lease, or any
assets or interest therein, or allow same to be assigned by operation of law or
otherwise, or sublet the Premises, or any part thereof, or use permit same to be
used for any other purpose than stated in the use clause hereof without the
written consent of Landlord, which consent will not be unreasonably withheld.
Notwithstanding the foregoing, in the event the Tenant desires to assign or
sublet the Premises, Tenant shall provide Landlord with not less than one
hundred twenty (120) days written notice of Tenant's request, specifying in
detail any and all terms of such assignment or sublease. Landlord reserves the
right to cancel and terminate this Lease within thirty (30) days upon receipt
of such notice from Tenant of its request to assign or sublet the Premises. In
the event Landlord consents to an assignment or sublease of the Premises, which
assignment or sublease results in rental payments in excess of the monthly
payments due and owing under the terms of this Lease, such excess rental
payments shall be deemed to be rental payments due and owing Landlord. Any
sale, hypothecation, transfer, assignment or subletting which is not in
compliance with the provisions of this Lease shall be voidable by Landlord and
shall, at the option of Landlord, constitute a default under this Lease.
Landlord's acceptance of rent directly from any subtenant, assignee or other
transferee shall not be construed as Landlord's approval or consent thereto nor
Landlord's agreement to accept the attornment of any subtenant in the event of
any termination of this Lease. In no event shall Landlord's consent to any
further assignment or subletting be construed as (i) relieving Tenant from the
obligation to obtain Landlord's express written consent to any further
assignment or subletting or (ii) releasing Tenant from any liability or
obligation hereunder whether or not then accrued, and Tenant shall continue to
be fully, jointly and severally liable hereunder. As a further condition to
Landlord's consent to any subletting, assignment or other transfer of part or
all of Tenant's interest in the Premises (i) Tenant shall be required to pay
Landlord's reasonable attorney's fees and other costs incurred in connection
with the review and execution thereof, (ii) any sublessee of part or all of
Tenant's interest in the Premises shall agree that in the event Landlord gives
such sublessee notice that Tenant is in default under this Lease, such
sublessee shall thereafter make all sublease or other payments directly to
Landlord, which payments will be received by Landlord without any liability
whether to honor the sublease or otherwise (except to credit such payments
against same due under this Lease, and such sublessee shall agree to attorn
to Landlord, or its successors and assigns, at its request should this Lease be
terminated for any reason, except that in no event shall Landlord or its
successors or assigns be obligated to accept such attornment; and (iii)
Landlord may require that Tenant not then be in default under this Lease in any
respect. In the event that Tenant files any type of petition in bankruptcy or
has same filed against it and Landlord does not elect to terminate this Lease
is deemed to have waived its right to terminate this Lease, and in the event
that the trustee or receiver appointed by the bankruptcy court attempts to
assume this Lease and thereupon assign it to a third party, then Landlord
shall have the right to terminate this Lease within thirty (30) days upon
gaining knowledge of such attempted assumption and assignment, or upon being
given written notice of same by Tenant, whichever is later. Upon any subletting
or assignment by Tenant any renewal options, expansion options, rights of first
refusal and/or exclusivity provisions shall become null and void.

If Tenant is a corporation, partnership, limited liability company, or other
entity and if, at any time during this Term, any part or all of the corporate
shares or ownership interests, as the case may be, Tenant shall be transferred
by sale, assignment, bequest, inheritance, operation of law, or other
disposition so as to result in a change in the present effective voting control
of Tenant by the person or persons owning a majority of such shares or interest
on the date of this Lease, Tenant shall properly notifying Landlord in writing
of such change, and Landlord may terminate this Lease at any time after such
change in control by giving Tenant thirty (30) days prior written notice of
such termination.



                                       3

<PAGE>   4
ALTERATIONS ADDITIONS, AND IMPROVEMENTS

5. Tenants shall not make or allow to be made any alterations, additions, or
improvements in or to the Premises without the prior written consent of
Landlord; such consent will not be unreasonably withheld, but Landlord may
impose, as a condition of such consent, such requirements as Landlord in its
sole discretion may deem reasonable or desirable, including without limiting the
generality of the foregoing, requirements as to the manner in which, the time or
times at which, and the contractor by whom such work shall be done. Such
alterations, additions, or improvements when made to the Premises by Tenant
shall be surrendered to Landlord and become the property of Landlord upon
termination in any manner of this Lease, but this clause shall not apply to
movable non-attached fixtures or furniture of Tenant, provided, however, if
prior to termination of this Lease, or within thirty (30) days thereafter,
Landlord so directs by written notice to Tenant, Tenant shall promptly remove
such alterations, additions, or improvements, which were placed in or on the
Premises by Tenant and which are designated in said notice and shall repair any
damage occasioned by such removal and in default thereof Landlord may affect
said removals and repairs at Tenant's expense. All work with respect to
alterations, additions, and improvements shall be done in a good and workmanlike
manner and diligently prosecuted to completion to the end that the improvements
on the Premises shall at all times be a complete unit except during the period
of work. Any such alterations, additions and improvements shall be performed and
done strictly in accordance with the laws and ordinances relating thereto, and
with the requirements of all carriers of insurance on the Premises and the Board
of Underwriters, Fire Rating Bureau, or similar organization. Tenant shall
obtain at its sole cost and expense all required licenses and permits. In
performing the work of any such alterations, additions or improvements, Tenant
shall have the work performed in such a manner so as not to obstruct the access
to or within the Building of any other tenant. Before commanding any such work
or construction in or about the Premises, Tenant shall notify Landlord in
writing of the expected date of commencement thereof. Landlord shall have the
right at any time and from time to time to post and maintain on the Premises
such notices as Landlord deems necessary to protect the Premises or the Project,
and Landlord from the liens of mechanic, laborers, materialman, suppliers or
vendors. If any liens are filed against Landlord or any part the Project as a
result of Tenant's work, Tenant shall cause same to be discharged by payment or
bonding within ten (10) days after such lien is filed.

LEGAL AND VIOLATIONS OF INSURANCE COVERAGE

6. Tenant shall not occupy or use, nor permit any portion of the Premises or any
other part of the project to be occupied or used for any business or purpose
which is unlawful in part or in whole or deemed to be disreputable in any
manner, or ??? hazardous on account of fire, nor permit anything to be done
which will in any way increase the rate of fire insurance on the Project or
contents, and in the event that, by reason of acts of Tenant, there shall be any
increase in rate of insurance on the Project or contents created by Tenant's
acts or conduct of business, then Tenant hereby agrees to pay such increase.

Tenant shall not use or occupy the Premises or permit the same to be used for
any purpose whatsoever other than the Permitted Use. Tenant shall procure, at
its sole expense, any permits and licenses required for the transaction of
business in the Premises and otherwise comply and cause the Premises to comply
with all applicable laws, ordinances and governmental regulations, as amended,
including, but not limited to the Americans With Disabilities Act and any
Environmental Laws.

Tenant acknowledges and understands that the proper tenant mix of the Building
is essential to the successful operation of the Building and that the
restriction against the unauthorized use of the Premises is not amended to act
as a restraint on trade but to protect and insure the correct tenant mix.

LAWS AND REGULATIONS

7. Tenant shall maintain the Premises in a clean and healthful condition and
comply with all laws, ordinances, orders, rules, and regulations (state,
federal, municipal, and other agencies or bodies having any jurisdiction
thereof) with reference to conditions, or occupancy of the Premises.

INDEMNITY, LIABILITY AND LOSS OR DAMAGE

8. By moving into the Premises or taking possession thereof, Tenant accepts the
Premises as suitable for the purpose for which the same are leased and accepts
the Project and each and every appurtenance thereof, and Tenant by said acts
waives any and all defects therein. Landlord shall not be liable to Tenant or
Tenant's officers, agents, employees, contractors, guests, invitees, licensees
or to any person claiming by, through or under Tenant for any injury to person,
loss or damage to property, or for loss or damage to Tenant's business,
occasioned by or through the acts or omissions of Landlord or any other person,
or by any other cause whatsoever except Landlord's gross negligence or willful
wrong to the extent Landlord is not prevented by law from contracting against
such liability, Tenant shall indemnify Landlord and save it harmless from all
suits, actions, damages, judgements, liability and expense in connection with
loss of life, bodily or personal injury or property damage arising from or out
of any occurrence in, upon, at or from the Project or the occupancy or use
thereof by Tenant, its officers, agents, contractors, employees, servants,
invitees, licensees or any other person claiming by, through or under Tenant. If
Landlord shall without fault on its part, be made a party to any action
commenced by or against Tenant, Tenant shall indemnify, defend and hold Landlord
harmless from any ????, expense, claims or actions arising out of any of the
foregoing (including, without limitation, any court costs and attorney's fees).
The provisions of this Paragraph "8" shall survive the expiration or earlier
termination of this Lease with respect to any claims or liability occurring
prior thereto.

BUILDING RULES AND REGULATIONS

9. Tenant and Tenant's officers, agents, employees, contractors and invitees
shall comply fully with all requirements of the Rules and Regulations which are
attached as Exhibit "B" and made a part hereof as fully set out herein. Landlord
shall at all times have the right to amend or supplement such Rules and
Regulations or to amend them in such reasonable manner as may be deemed
advisable for Premises and the Project. Such additional Rules and Regulations
shall be forwarded to Tenant in writing and shall be carried out and observed by
Tenant.

                                       4
<PAGE>   5

ENTRY FOR REPAIRS AND INSPECTION

10.  Tenant will permit Landlord or their officers, agents, contractors and
representatives, the right to enter into and upon all parts of the Premises, at
all reasonable hours to inspect same or clean or make repairs or alterations or
additions as Landlord may deem necessary or for making repairs, alterations or
additions to adjacent amenities or any other premises in the Building and
Tenant shall not be entitled to any abatement or reduction of rent by reason
thereof. In the event of an emergency, Tenant hereby grants to Landlord the
right to enter the Premises at any time. In addition, Tenant shall permit
Landlord or Landlord's agent and any other person authorized by the same to
enter the Premises during the last six months of the Term for the purpose of
exhibiting the Premises to prospective lessees.

NUISANCE

11.  Tenant will conduct its business, and control its agents, employees,
invitees and visitors in such a manner as not to create any nuisance, interfere
with, annoy, or disturb other tenants or Landlord in the management of the
Building.

EMINENT DOMAIN AND FORCE MAJEURE

12.  (A) If the whole of the Premises or so much thereof as to render the
     balance unusable by Tenant is taken under power of eminent domain, or sold,
     transferred or conveyed in lieu thereof, this Lease shall automatically
     terminate as of the date of such condemnation, or as of the date possession
     is taken by the condemning authority, whichever is later. No award for any
     partial or entire taking shall be apportioned and Tenant hereby releases
     any claim to and assigns to Landlord any award which may be made in such
     taking or condemnation, together with any and all rights of Tenant now or
     hereafter arising in or to the same or any part thereof, provided, however,
     that nothing contained herein shall be deemed to give Landlord any interest
     in, or to require Tenant to assign to Landlord, any award made to Tenant
     for the taking of personal property and fixtures belonging to Tenant and
     removable by Tenant at the expiration of the term hereof as provided
     hereunder or for the interruption of, or damage to, Tenant's business. In
     the event of a partial taking, or a sale, transfer or conveyance in lieu
     thereof, which does not result in a termination of this Lease, pursuant to
     the foregoing, the rent shall be reduced in proration of the area taken,
     effective on the date physical possession is taken by the condemning
     authority.

     (B)  Landlord shall not be liable or responsible for any loss or damage to
     any property or person occasioned by theft, fire, act of God, public enemy,
     injunction, riot, strike, insurrection, war, court order, requisition or
     order of a government body or authority, or other matter beyond the
     control of Landlord or for any damage or inconvenience which may arise
     through repair or alteration of any part of the Project or failure to make
     any such repairs, or from any cause whatever, unless caused solely by
     Landlord's gross negligence.

LANDLORD'S LIEN

13.  As security for the performance of the obligations of the Tenant under
this Lease, the Tenant hereby grants the Landlord a security interest to all of
the property now owned or hereafter acquired by the Tenant which is located in
the Premises and all proceeds and products thereof. The Tenant shall not remove
any of such personal property from the Premises until all of the Tenant's
obligations under this Lease have been satisfied in full. Without excluding any
other manner of notice, any requirement for reasonable service to the Tenant of
the Landlord's intention to dispense of any property pursuant to the
enforcement of such security interest will be met if such notice is given at
least ten days before the close of such disposition. Any sale made pursuant to
the enforcement of such security interest will be deemed to have been a public
sale conducted in a commercially reasonable manner if held at the Premises
after advertisement of the time, place, method of sale and a general
description of the property to be sold in a daily newspaper published in the
country in which the Premises is located, for five (5) consecutive days before
the date of sale. The Tenant agrees to execute and deliver to the Landlord such
financing statements, continuation statements and other instruments as Landlord
might reasonably require to perfect, protect or continue the foregoing security
interest within ten (10) days after written request therefor.

ABANDONMENT

14.  If the Premises are abandoned or vacated by Tenant, Landlord shall have
the right, but not the obligation, to: (a) raise same for the remainder of the
period covered hereby; and if the rent is not received through such reletting
at least equal to the rent provided hereunder, Tenant shall pay and satisfy any
deficiencies between the amount of rent called for and that received through
reletting and all expenses incurred by any such reletting, including but not
limited to, the cost of renovating, altering and decorating for a new occupant,
and/or (b) provide for the storage of any personal property remaining in the
Premises without liability of any kind or nature for the cost of storage or the
return of the personal property to Tenant or take title to the abandoned
personal property which title shall pass to Landlord under this Lease as a Bill
of Sale without additional payments or credit from Landlord to Tenant.
Notwithstanding the foregoing, during the last ninety (90) days of the term of
this Lease if Tenant removes a substantial portion of Tenant's property or
Tenant has been in physical absence for ten (10) days it shall, at Landlord's
option constitute an abandonment and Landlord may enter the Premises for
purposes of renovating, altering and decorating the Premises for occupancy at
the end of the Term by a new tenant without in any way affecting Tenant's
obligation to pay rent and comply with all other terms and conditions of this
Lease. Nothing herein shall be construed as in any way denying Landlord the
right, in case of abandonment, of the Premises, or other breach of this Lease
by Tenant, to treat the same as an entire breach, and, at Landlord's option,
immediately sue for the entire breach of this Lease and any and all damages
occasioned Landlord thereby.

HOLDING OVER

15.  In case of holding over by Tenant after expiration or termination of this
Lease, Tenant shall pay as liquidated damages double rent for the entire
holdover period, and shall pay all attorney's fees, and expenses incurred by
Landlord in enforcing its rights hereunder. No holding over by Tenant after the
terms of this Lease, either with or without the content and acquiescence of
Landlord, shall operate to extend this Lease for a longer period than one
month; and holding over with the consent of Landlord in writing shall
thereafter constitute a tenancy Agreement from month to month, subject to all
the terms and conditions of this Lease. The foregoing provisions of this
Paragraph 15 are in addition to and do not affect Landlord's right of re-entry
or any other rights of Landlord hereunder or as otherwise provided by law.

                                       5

<PAGE>   6
ATTORNEY'S FEES

16. In case Tenant defaults in the performance of any of the terms, covenants,
agreements or conditions contained in this Lease, and Landlord places the
enforcement of this Lease, or any part thereof, or the collection of any rent
due, or to become due hereunder or recovery of the possession of the Premises in
the hands of an attorney or files upon the same, Tenant agrees to pay Landlord's
reasonable attorney's fees, and payment of the same shall be secured in like
manner as is herein provided, is to all remedies which may be invoked by
Landlord to secure payment of rent.

DAMAGE OR DESTRUCTION

17. If the Premises or the Building in which the Premises are located shall be
damaged by any cause or means whatsoever not caused or contributed to by the
negligence or fault of Tenant, its employees, agents, contractors, invitees or
visitors, and if insurance proceeds have been made available therefor, and if
said damage can be repaired within a period of ninety (90) working days by using
standard working methods and procedures, Landlord shall within a reasonable time
after the occurrences of said damage, and to the extent of the insurance
proceeds available therefor, enter and make repairs, and this Lease shall not be
affected but shall continue in full force and effect. However, if said damage
cannot be repaired within a period of ninety (90) working days by using standard
working methods and procedures, then this Lease shall cease and terminate as of
the date of such occurrence, and Tenant shall pay rent hereunder to such date
and immediately surrender the Premises to Landlord, unless within a period of
sixty (60) working days from the date of such occurrence Landlord shall elect to
keep this Lease in force and to restore the Premises to substantially the
condition as existed prior to the date of such occurrence by giving Tenant
written notice of such election within said sixty (60) working day period. If
Landlord so elects to continue the Lease and restore the Premises, Landlord
shall within a reasonable time after the date of the notice of said election
enter and make repairs, and this Lease shall not be affected, except that rents
hereunder shall be equitably abated while such repairs are being made for the
period of time and in the proportion that the Premises are untenable. If,
however, such damage is contributed to or results from the fault of Tenant,
Tenant's employees, agents, contractors, invitees or visitors, and if Landlord
does not have insurance covering such damage, such damage shall be repaired by
and at the expense of Tenant under the consent, direction and supervision of
Landlord, and the rent shall continue without abatement or reduction. The
completion of the repairs of all such damages is subject to reasonable delays
resulting from survey of such damage, obtaining plans and letting contracts for
repair, adjustment or insurance loss, strikes, labor difficulties,
unavailability of material, or other causes beyond the control of the party
obligated to make such repairs. Notwithstanding anything to the contrary
contained in this Paragraph 17, Landlord shall not have any obligation
whatsoever to repair, reconstruct or restore the Premises on account of the
damage resulting from any casualty covered under this Paragraph 17 which occurs
during the last twelve (12) months of the Term (or any extension thereof).
Landlord shall not be required to repair any injury or damage by any cause, or
to make any repairs or replacement of any property insured or required to be
insured under this Lease by Tenant.

INSURANCE

18. Tenant agrees during the Term (and any extension thereof) to carry: a broad
form comprehensive policy of public liability insurance (to include Premises/
Operations, Independent Contractors, Broad Form Contractual in support of
Tenant's indemnities in this Lease Agreement and Personal Injury Liability
Coverage) covering the Premises in an amount of not less than $1,000,000
combined single limit personal injury and property damage insurance; fire and
extended coverage insurance covering all alterations, additions, partitions,
improvements made or placed by Tenant in the Premises, and contents placed by
Tenant in the Premises; Workers' Compensation Insurance in an amount equal to
the minimum statutory limit (as the same hereafter may be amended): Employers
Liability Insurance in an amount of not less than $500,000; and, Automobile
Liability Insurance in an amount not less than $300,000, all with companies
satisfactory to Landlord in the name of Tenant (with Landlord and, if requested
by Landlord, any mortgages, trust deed holder, ground lessor or secured party
with a substantial interest in this Lease and/or the Project named as additional
insureds in the policy or by endorsement). Tenant also agrees to pay the
premiums therefor and to deliver copies of said policies and/or endorsement
thereto to Landlord, and the failure of Tenant to either obtain said insurance
or deliver copies of said policies or certificates thereof to Landlord shall
permit Landlord to procure said insurance and pay the requisite premiums
therefore, which premiums shall be repayable to Landlord with the next monthly
rental payment. Each insurer under the policies required hereunder shall agree
by endorsement on the policy issued by it or by independent insurance furnished
to Landlord that will give Landlord no less than thirty (30) days written notice
before the policy or policies in question shall be altered or canceled. All such
insurance policies shall be primary, noncontributable and shall contain
cross-liability coverage or an endorsement. The amounts of such insurance
required hereunder shall be subject to adjustment from time to time as requested
by Landlord or as requested by any ground lessor or lender with an interest in
the Project.

TRANSFER OF LANDLORD'S RIGHTS

19. Landlord shall have the right to transfer and assign, in whole or in part,
all and every feature of its rights and obligations hereunder and in the
Building and property referred to herein. Such transfers or assignments may be
either in a corporation, trust company, individual, or group of individuals, and
howsoever made are to be in all things respected and recognized by Tenant.

In the event of the transfer and assignment by Landlord of its interest in this
Lease to any person expressly assuming Landlord's obligation under this Lease,
Landlord shall thereby be released from any further obligations hereunder, and
Tenant agrees to look solely to such successor in interest of Landlord for
performance of such obligations. Any security given by Tenant to secure
performance of Tenant's obligations hereunder may be assigned and transferred by
Landlord to such successor in interest, and Landlord shall thereby be discharged
of any further obligation relaying thereto.

EVENTS OF DEFAULT AND REMEDIES

20. The following shall be deemed a default by Tenant under this Lease: (a) If
Tenant fails to pay when due any installment of rent or any other payment to
Landlord as herein provided; and if Tenant fails to comply with any term,
provision, condition, or covenant of this Lease other than the payment of rent,
or any of the Rules and Regulations new or hereafter established by Landlord;
(b) Tenant abandons, deserts or vacates the Premises; (c) any petition is filed
by or against Tenant under any section or chapter of the Bankruptcy Code, as
amended, or under any similar law or statute of the United States or of any
state thereof; (d) Tenant becomes insolvent or makes a transfer in fraud of
creditors; (e) Tenant makes an assignment for benefit of creditors, or (f) a
receiver is appointed for Tenant or any of the assets of Tenant. Upon the
occurrence of any such event or default, Landlord


                                       6
<PAGE>   7
shall have the option to pursue any one or more of the following remedies or
any other remedy that it may serve at law or equity, without any notice or
demand whatever.

     (1)  Terminate this Lease in which event Tenant shall immediately surrender
     the Premises to Landlord, and if Tenant fails to do so, Landlord may,
     without prejudice to any other remedy which Landlord may have for
     possession of the Premises and expel or remove Tenant and any other person
     who may be occupying said Premises or any part thereof, by force if
     necessary, without being liable for prosecution of any claim for damages
     therefor.

     (2)  Take immediate possession of the Premises, but if Tenant shall fail to
     vacate the Premises, Landlord may without notice and without prejudice to
     any other remedy Landlord may have, enter upon and take possession of the
     Premises and expel or remove Tenant and its effects, "by force if
     necessary", without being liable to prosecution or any claim for damages
     therefor, and Tenant agrees to indemnify Landlord for all loss, damage, and
     expense including reasonable attorney's fees which Landlord may suffer by
     reason of such termination.

     (3)  Declare the entire amount of the rent which would have become due and
     payable during the remainder of the Term to be due and payable immediately,
     in which event, Tenant agrees to pay the same at once, together with all
     rents therefor due, to Landlord at the address specified herein or
     hereunder, provided, however, that such payments shall not constitute a
     penalty or forfeiture or liquidated damages, but shall actually constitute
     payment in advance of the rent for the remainder of the Term. The
     acceptance of such payment by Landlord shall not constitute a waiver or any
     failure of Tenant thereafter occurring to comply with any term, provision,
     condition or covenant of this Lease.

     (4)  Relet the Premises and receive the rent therefor, and in such event,
     Tenant shall pay Landlord the cost of renovating, repairing and altering
     the Premises for a new tenant or tenants and any deficiency that may arise
     by reason of such reletting, on demand, at the address of Landlord
     specified herein or hereunder provided, however, the failure or refusal of
     Landlord to relet the Premises shall not release or affect Tenant's
     liability for rent or for damages and such rent and damages shall be paid
     by Tenant on the date specified herein.

     (5)  Landlord may, as agent of Tenant, do whatever Tenant is obligated to
     do by the provisions of this Lease and may enter the Premises, "by force if
     necessary", without being liable to prosecution or any claim or damages
     therefor, in order to accomplish this purpose. Tenant agrees to reimburse
     Landlord immediately upon demand for any expenses which Landlord may incur
     in thus effecting compliance with this Lease on behalf of Tenant, and
     Tenant further agrees that Landlord shall not be liable for any damages
     resulting to Tenant from such action, whether caused by the negligence of
     Landlord or otherwise.

Pursuit of any of the foregoing remedies shall not preclude pursuit of any of
the other remedies herein provided or any other remedies provided by law and/or
equity.

No act or thing done by Landlord or its agents during the Term hereof shall be
deemed an acceptance of a surrender of the Premises, and no agreement to accept
a surrender of the Premises shall be valid unless made in writing and signed by
Landlord. The mention in this Lease of any particular remedy shall not preclude
Landlord from any other remedy Landlord might have, either in law or in equity,
nor shall the waiver of or redress for any violation of any covenant or
condition in this Lease or any of the Rules and Regulations attached hereto or
hereafter adopted by Landlord, prevent a subsequent act, which would have
originally constituted a violation, from having all the force and effect of an
original violation. The receipt by Landlord of rent with knowledge of the breach
of any covenant in this Lease contained shall not be deemed a waiver of such
breach. The failure of Landlord to enforce any of the Rules and Regulations
attached hereto, or hereafter adopted, against Tenant and/or any other tenant of
the Project shall not be deemed a waiver. Waiver of said Rules and Regulations
by Landlord shall be in writing and signed by Landlord. (In case it should be
necessary or proper for Landlord to bring any action under this Lease to consult
or place said Lease or any amounts payable by Tenant thereunder, with an
attorney ???? or for the enforcement of any of the Landlord's rights hereunder,
then Tenant agrees in each and any such case to pay to Landlord reasonable
attorney's fees.)

In the event of any default by Landlord, Tenant shall give Landlord written
notice specifying such default with particularity, and Landlord shall thereupon
have thirty (30) days (or such longer as may be required in the exercise of due
diligence) in which to cure any such default. Unless and until Landlord fails
to cure any default after such notice, Tenant shall not have any remedy or
cause of action or reason thereafter. All obligations of Landlord hereunder
shall be constructed as covenants, not conditions. The term "Landlord" shall
mean the owner, for the time being, of the Project, and in the event of
transfer by such owner of its interest in the Project, such owner shall
thereupon be released and discharged for all covenants and obligations of the
Landlord thereafter accruing, that such covenants and obligations shall be
binding during the Term upon such new owner for the duration of such owner's
ownership. Notwithstanding any other provision hereof, in the event of any
breach of default by Landlord any term or provision of this Lease, Tenant
agrees to look entirely to the equity or interest then owned by Landlord in the
Project; however, in no event shall any deficiency judgment or any money
judgment of any kind be sought or obtained against any party Landlord.

OTHER DEFAULTS

21.  In the event Tenant, or Tenant's subsidiary or affiliate, shall have other
leases for other premises in the Project, any default by Tenant or Tenant's
subsidiary or affiliate under such other lease shall be deemed to be a default
herein and Landlord shall be entitled to enforce all rights and remedies as
provided for a default herein.


                                       7
<PAGE>   8
BIND AND INURE

22. The obligations of this Lease shall be binding upon and inure to the benefit
of the parties hereto and their respective successors and assigns, except that
Landlord named herein and each successive owner of the Premises shall be liable
only for the obligations occurring during the period of its ownership. Whenever
the Project is owned by a trustee or trustees, the obligations of Landlord shall
be binding upon Landlord's trust estate, but not upon any trustee, beneficiary
or shareholder of the trust individually. In the event this Lease is executed by
two or more persons or entities as "Tenant", the liability of each shall be
joint and several.

QUIET POSSESSION

23. Landlord hereby covenants that Tenant, upon paying rent as herein reserved,
and performing all covenants and agreements herein contained on part of Tenancy,
may have the peaceable and quiet enjoyment and possession of the Premises.

POSSESSION

24. If for any reason the Premises shall not be ready for occupancy by Tenant at
the Commencement Date, this Lease shall not be affected thereby, nor shall
Tenant have any claim against Landlord by reason thereof, but no rent shall be
payable for the period during which the Premises shall not be ready for
occupancy. All claims for damages arising out of any such delay are waived and
released by Tenant. With respect to the foregoing, if delivery of possession of
the Premises shall be delayed beyond the Commencement Date, it is understood and
agreed that the Commencement Date shall be extended to the date that the
Premises are tendered to the Tenant in which event the Term shall be
correspondingly extended. In the event of such delay in tendering the Premises
to Tenant, Landlord shall not be liable to Tenant for any damage whatsoever
resulting from the delay in the delivery of possession of the Premises.
Notwithstanding the foregoing, it is understood that if and to the extent that
Landlord is unable to deliver timely possession of the Premises to Tenant due to
delays by Tenant, then the rent reserves shall commence to accrue on the date
possession of the Premises would have been delivered to Tenant but for the
delays of Tenant. If permission is given to Tenant to occupy the Premises prior
to the Commencement Date, such occupancy shall be subject to all the provisions
of this Lease (including the payment of rent) except those relating to the Term.

CONDITION OF PREMISES

25. Tenant acknowledges that neither Landlord nor any agent of Landlord have
made any representation or warranty with respect to the Premises or the Project
or with respect to the suitability of either for the conduct of Tenant's
business or profession. The taking of possession of the Premises by Tenant shall
conclusively establish that the Premises and the Project were at such time in
satisfactory condition.

ESTOPPEL CERTIFICATE

26. Within five (5) days after request thereof by Landlord, Tenant agrees to
execute and deliver in recordable form an estoppel certificate to any proposed
mortgagee or purchaser, or to Landlord, certifying that this lease is unmodified
and in full force and effect (or, if there has been any modification, that the
same is in full force and effect as modified, and stating the modification),
that there are no defenses or offsets thereto (or specifically stating those
claimed by Tenant), and the dates to which Rent and other charges have been
paid, and stating such other matters as Landlord may require concerning the
lease or the Premises. In the event Tenant shall fail to return a fully executed
copy of such certificate to Landlord within the referenced period, then Tenant
shall be deemed to have approved and confirmed all of the terms, certifications
and representations contained in such certificate. Tenant irrevocably appoints
Landlord as attorney-in-fact for the Tenant with full power and authority to
execute and deliver in the name of Tenant such certificate if Tenant fails to
deliver the same within such period and such certificate is signed by Landlord
shall be fully binding on Tenant.

SIGNS

27. Tenant will not place or suffer to be placed or maintained on any exterior
door, wall or window of the Premises any sign, awning or canopy, or advertising
matter or other thing of any kind, and will not place or maintain any
decoration, lettering or advertising matter on the glass of any window or door
of the Premises without first obtaining Landlord's prior written approval and
consent in such instance. Tenant further agrees to maintain any such sign,
awning, canopy, decoration, lettering, advertising matter or other thing as may
be approved, in good condition at all times.

PERSONAL PROPERTY TAXES

28. With respect to Tenant's fixtures, furnishings, equipment and all other
personal property located in the Premises, Tenant shall pay, prior to
delinquency all taxes assessed against or levied thereon and when possible,
shall cause same to be assessed and billed separately from the property of
Landlord, but if same shall be assessed and taxed with the property of Landlord,
Tenant shall pay to Landlord its share of such taxes within ten (10) days after
Landlord's delivery to Tenant of a statement in writing setting forth the amount
of such taxes applicable to Tenant's property. In addition Tenant shall pay
promptly when due all taxes imposed upon Tenant's rent, gross receipts, charges
and business operations.

SUBORDINATES

29. Tenant hereby subordinates this Lease and all rights of Tenant hereunder to
any mortgage or mortgages, or vendor's lien, or similar instruments which now
are or which may from time to time be placed upon the Project, and such mortgage
or mortgages or liens or other instruments shall be superior to and prior to
this Lease. Tenant further covenants and agrees that if the mortgage or other
lien holder acquires the Premises as a purchaser at any such foreclosure sale
(any such mortgagee or other lien-holder or purchaser of the foreclosure sale
being such hereunder referred to as the "Purchaser at Foreclosure"). Tenant
shall thereafter, but only at the option of the Purchaser at Foreclosure, as
evidenced by the written notice of its election given to Tenant within a
reasonable time thereafter, remain bound by ??? or otherwise to the same effect
as if a new and identical Lease between the Purchaser at Foreclosure, as
Landlord, and Tenant, as tenant, had been entered into for the remainder of the
Term in effect at the institution of the foreclosure proceedings. Tenant agrees
to execute any instrument or instruments which may be deemed necessary or
desirable further to effect the subordination of this Lease to each such
mortgage, lien or instrument or to confirm any election to continue the Lease in
effect in the event of foreclosure, as above provided. Tenant hereby irrevocably
appoints Landlord as its special attorney-in-fact to execute and deliver any
document or documents provided for herein for and in the name of Tenant. Such
power, being coupled with and interest, is irrevocable.


                                       8

<PAGE>   9
SEVERABILITY CLAUSE

30.  If any clause or provision of that is illegal, invalid, or unenforceable
under present or future laws effective during the Term, then and in that event,
it is the ?? of the parties hereto that the remainder of this Lease shall not be
affected thereby, and it is also the intention of the parties to this Lease that
is ?? of each clause or provision that is illegal, invalid, unenforceable, there
be added as a part of this Lease, a clause or provision as similar in terms to
such illegal, invalid or unenforceable clause or provision as may be possible
and be legal, valid and enforceable. The caption of each paragraph hereof is
added as a matter of convenience solely and shall be considered to be of no
effect on the construction of any provision or provisions of this Lease.

SECURITY DEPOSIT

31.  Upon the occurrence of any event of default by Tenant, Landlord may, from
time to time, without prejudice to any other remedy use the Security Deposit
paid to Landlord by Tenant as herein provided to the extent necessary to make
good any arrears of rent and other damage, injury, expenses or liability caused
to Landlord by such event of default. If any portions of said deposit is so used
or applied, Tenant shall, within five (5) days after written demand therefor,
deposit cash with Landlord is an amount sufficient to restore the security
deposit to its original amount. Tenant shall not be entitled to interest on the
security deposit. Tenant shall not grant anyone a security interest of any kind
in such security deposit and no such security agreement shall be binding on
Landlord. If Tenant shall fully and faithfully perform every provision of this
Lease to be performed by it, the security deposit, or any balance thereof
remaining, shall be returned to Tenant at the expiration of the Term and upon
Tenant's vacation of the Premises. Such Security Deposit shall not be considered
as advance payment of rental or a measure of Landlord's damages in case of
default by Tenant.

WAIVER OF SUBROGATION

32.  Tenant hereby waives all right of subrogation by any insurance company
issuing policies carried by Tenant including, without limitation, the Premises,
Tenant's fixtures, personal property, or leasehold improvements, or Tenant's
business.

ADJUSTMENT OF RENTAL

33.  (A)  Operating Expenses:

          (1)  The term "Operating Expenses" shall mean all costs of management,
          operating and maintenance of the land, the Project and improvements
          and appurtenances thereon, all accrued and based on a calendar year
          insurance premiums period, as determined by generally accepted
          accounting principles, including by way of illustration but not
          limitation, real estate taxes, personal property taxes; other taxes,
          assessments and governmental charges (including taxes on rents of
          services); expenses for abatements, utilities, insurance premiums,
          janitorial and cleaning services, licenses, permits and inspection
          fees, heating and cooling, maintenance and repairs, general
          administration costs and expenses, labor and supplies, capital
          expenditures which result in a substantial labor or cost saving device
          or operation in which case the capital expenditures shall be amortized
          over ten years and included on an annual basis in the Operating
          Expenses, whether such Operating Expenses, or any portion thereof, are
          paid by the Landlord, directly by the Tenant, excluding, however,
          depreciation, capital expenditures which do not result in a
          substantial labor or cost saving device cost of Tenant improvements
          and commissions paid for leasing.

          (2)  It is agreed that the Base Rent provided for herein includes the
          Tenant's share of Operating Expenses during the first year of the
          Term. If the amount of such Operating Expenses for the entire Project
          exceed, in any calendar year, the actual base year operating expenses
          for 1998, Tenant shall pay its share of the excess in the same manner
          and with the same interest so stated throughout this Paragraph 33
          within ten (10) days of billing, as additional rental the Tenant's
          share of such excess.

          (3)  It is further agreed and understood that approximately January
          1st of each calendar year or as soon thereafter as the information can
          be obtained, Landlord shall notify Tenant of such calculations and (1)
          effective each January 1st, during the Term and on the first (1st) day
          of each of the succeeding eleven (11) months of each calendar year.
          Tenant shall pay the Landlord one-twelfth (1/12) of its share of the
          increase in annual Operating Expenses over and above actual base year
          operating expenses.

     (B)  If the average occupancy in any calendar year is less than ninety
          percent (90%), then the Operating Expenses for such year shall be
          adjusted to reflect what the expenses would have been at an occupancy
          of ninety-five percent (95%).

     (C)  It is further agreed that the provisions of Paragraph 33 shall
          survive the expiration or earlier termination of this Lease and be
          applicable to such portion of the calendar year as this Lease was in
          effect.

     (D)  In no event shall any provision of this Paragraph 33 result in any
          reduction in the Base Rent.

SALE OF ASSETS

36.  Tenant shall not transfer any portion of its assets outside the ordinary
course of its business so that the effect causes the Tenant to default under
Paragraph 35 of this Lease.


                                       9
<PAGE>   10
INTEREST ON PAST DUE OBLIGATIONS

37. Any interest due from Tenant hereunder which is not paid when due shall bear
interest at the rate of eighteen percent (18%) per annum from the due date until
paid, unless otherwise specifically provides herein, but the payment of such
interest shall not excuse or cure any default by Tenant under this Lease.

RELOCATION OF TENANT

38. At any time after Tenant's occupancy, upon at least thirty (30) days'
written notice to tenant, Landlord shall be entitled to relocate Tenant from the
Premises above to another space in the Building or to any other building in the
Project (Relocated Suite) provided that: (a) the Relocated Suite shall provide
Tenant with at least as much net rentable area as the Premises; (b) the
Relocated Suite shall provide Tenant with substantially the same improvements as
are provided to Tenant in the Premises at no additional cost to Tenant; and (c)
the reasonable expenses incurred by Tenant in relocation to the Relocated Suite
shall be borne by Landlord. Upon any such relocation, Landlord and Tenant shall
execute an addendum to amend this Lease to describe the Relocated Suite; and, in
any event, upon such or relocation being effected this Lease thereafter shall no
longer apply to the portion of the Building described in Section 4 above, but
shall be deemed to apply to the Relocated Suite.

INABILITY TO PERFORM

39. This Lease and the obligations of Tenant hereunder shall not be affected or
impaired because Landlord is unable to fulfill any of its obligations hereunder
or is delayed in doing so, if such inability or delay is caused by reason of
strike or other labor troubles, or act of God, or any other cause beyond the
control of Landlord.

INCORPORATION OF PRIOR AGREEMENTS; AMENDMENTS

40. This Lease contains all of the agreements of the parties hereto with respect
to any matter covered or mentioned in this Lease and no prior agreement or
understanding pertaining to any such matter shall be effective for any purpose.
No provision of this Lease may be amended or added to except by an agreement in
writing signed by the parties hereto or their respective successors in interest.
Any written addenda to this Lease, when signed or initialed by the contracting
parties shall be deemed a part of this Lease to the same full extent as if
incorporated herein.

ACCORD AND SATISFACTION

41. No payment by Tenant or receipt by Landlord of a lesser amount than that
stipulated herein for rent, additional rent or any other charge shall be deemed
to be other than on account of the partial stipulated rent, additional rent or
other charge then due, nor shall any endorsement or statement on a check or
letter accompanying any check or payment be deemed an accord and satisfaction
and Landlord may accept such check or payment without prejudice to Landlord's
rights to recover the balance of such rent, additional rent or other charges or
pursue any other remedy in this Lease, at law or in equity.

TIME OF ESSENCE

42. Time is of the essence with respect to the performance of every provision of
this Lease in which time of performance is a factor, except that whenever a
period of time as herein prescribed for action to be taken by Landlord, Landlord
shall not be liable or responsible for and there should be excluded from the
computation of any such period of time, any delays due to restrictions or any
other causes of any kind whatsoever which are beyond the reasonable control of
the Landlord.

NO BROKER OR AGENT OF TENANT

43. Tenant warrants that is has had no dealing with any broker or agent in
connection with the negotiation or execution of this Lease, other than: (a)
Landlord's broker or agent, if any, and, (b) a broker or agent authorized to act
as co-broker under a written co-brokerage agreement with Landlord, if any.
Tenant agrees to hold harmless and indemnify Landlord as to any claim which may
be asserted by any broker or agent which has acted for or on behalf of Tenant in
connection with the negotiation or execution of this Lease unless such claim
expressly and specifically has been authorized and is due under the terms of
such a written co-brokerage agreement.

LEASE EFFECTIVE UPON EXECUTION

44. Delivery of this Lease, duly executed by Tenant, constitutes an offer to
lease the Premises as herein set forth, and under no circumstances shall such
delivery be deemed to cause an option or reservation to lease the Premises for
the benefit of Tenant. This Lease shall only become effective and binding upon
execution hereof by Landlord and delivery of a signed copy to Tenant.

NOTICES

45. All other notices or communications which may be required or which may be
given under the terms of this lease shall be in writing and shall be deemed
sufficiently given or served if personally delivered to the other party, or if
sent by registered certified mail, return receipt requested, postage prepaid, or
by overnight delivery service such as Federal Express, Airborne, etc., in all
cases addressed to the parties hereto at the respective addresses set out in the
Basic Provisions above. The date of service by mail of any notice or other
communication required or which may be given under the terms of this lease shall
be two (2) dates after the date on which the same is deposited in the United
States mail by the party giving such notice. The date of service by personal
delivery shall be the date of such delivery. The date of service by overnight
delivery service shall be the day after the same is deposited with such
overnight delivery service. Any address or name specified for notices may be
changed by notice given in accordance with the provisions of this section. The
inability to deliver because of a changed address of which no notice was given
or the rejection or other refusal to accept a notice or other communication
shall not be deemed to affect the service of such notice.

EXECUTED and delivered as of the day and year first above written.


Tenant:   medibuy.com                    LANDLORD: TWENTY FIRST PROPERTIES, INC.
       -----------------------------               an Oklahoma Corporation
          a Delaware Corporation


By:       /s/ CHARLIE SMITH              By:      /s/ PAUL D. WILSON
   ---------------------------------        ---------------------------------
            Charlie Smith                            Paul D. Wilson


Title:        President                  Title:         President
      ------------------------------           ------------------------------


                                       10
<PAGE>   11

                                  EXHIBIT "A"

                     SPECIFICATIONS OF TENANT IMPROVEMENTS

Landlord agrees to provide Tenant with the following specific improvements
listed below. Any changes or upgrades in the items listed below will be paid
for by Tenant. These changes or requests must be made in writing to Landlord
and must be paid within one (1) week of the completion of work. Any
modifications desired by Tenant are to be approved by Landlord and carried out
by Landlord's general contractors.


                                  [FLOOR PLAN]


                                  SUITE 2526-C
                           1,324 RENTABLE SQUARE FEET

1.    Landlord shall paint space with color to be selected by Tenant from
      samples provided by Landlord including the exterior frame and door of
      Suite 2526-C.

2.    Landlord shall carpet space with color to be selected by Tenant from
      samples provided by Landlord.

3.    Landlord shall replace stained or damaged ceiling tiles as needed
      throughout the suite.

4.    Within ninety (90) days of the commencement date, Landlord agrees to
      install new carpet in the common area and to touch up the paint in the
      common area hallway.


"LANDLORD"                                "TENANT"

Twenty First Properties, Inc.,            medibuy.com
an Oklahoma Corporation                   a Delaware Corporation


By:  /s/ PAUL D. WILSON                   By: /s/ CHARLIE SMITH
   ------------------------------            ------------------------------
         Paul D. Wilson                           Charlie Smith


Title:     President                      Title:      President
      ---------------------------               ---------------------------
<PAGE>   12
                                  EXHIBIT "B"

                         BUILDING RULES AND REGULATIONS


1.  No additional locks or belts of any kind shall be placed upon any of the
doors or windows by Tenant, nor shall any changes be made in existing locks or
the mechanism thereof without the prior written consent of Landlord. Tenant
must, upon the termination of its tenancy, restore to Landlord all keys either
furnished to or otherwise procured by Tenant, and in the event of the loss of
any keys so furnished, Tenant shall pay to Landlord the cost thereof.

2.  Directories will be placed by Landlord, at its own expense, in conspicuous
places in the Building. No other directories shall be permitted, unless
previously consented to by Landlord in writing.

3.  Tenant will refer all contractors, contractor's representatives and
installation technicians, rendering any service to Tenant, to Landlord for
Landlord's supervision, approval and control before performance of any
contractual service. This provision shall apply to all work performed in the
Project including installations of telephones, telegraph equipment, electrical
devices and attachments and installations of any service affecting floors,
walls, woodwork, trim, windows, ceilings, equipment or any other physical
portion of Building.

4.  Movement in or out of the Building of furniture or office equipment, or
dispersion or receipt by Tenant of any merchandise or materials which require
use of elevators or stairways, or movement through Building entrances or lobby
shall be restricted to hours designated by Landlord. All such movement shall be
under supervision of Landlord and in the manner agreed between Tenant and
Landlord by prearrangement before performance. Such prearrangement initiated by
Tenant will include determination by Landlord and subject to its decision and
control as to the time, method and routing of movement and as to limitations
imposed for safety or other concerns which may prohibit any article, equipment
or any other item from being brought into the Building. Tenant is to assume all
risk as to damage to articles moved and injury to persons or public engaged or
not engaged in such movement, including equipment, property, and personnel of
Landlord if damaged or injured as a result of acts in connection with carrying
out this service for Tenant, from time of entering property to completion of
work, and Landlord shall not be liable for acts of any person engaged in, or any
damage or loss to any of said property or persons resulting from any act in
connection with such service performed for Tenant.

5.  No signs, advertisements or services shall be painted or affixed on or to
any windows or doors, or other parts of the Building or the Project, exempt of
color, size and style and in such places, as shall be first approved in writing
by Landlord. All signs will be contracted for by Landlord at the rate fixed by
Landlord from time to time, and Tenant will be billed and pay for such service
accordingly.

6.  If any Premises becomes infested with vermin, the Tenant, at its sole cost
and expense, shall cause its premises to be exterminated from time to time to
the satisfaction of the Landlord and shall employ such exterminations as shall
be approved by Landlord.

7.  Tenant and Tenant's agents, employees, guests and invitees shall not bring
into or keep in the Building, including but not limited to the Premises and the
Common Area, any explosives, firearms or weapons, including any licensed
concealed firearms. Tenant shall advise all agents, employees, guests and
invitees of this rule and shall enforce this rule upon the Premises. Tenant is
to assume all risk as to damage to real or personal property and injury to
persons as a result of Tenant's agents, employees, guests and invitees bringing
such items into the Building, including but not limited to the Premises and the
Common Area. Landlord shall not be liable for the acts of any persons bringing
explosives, firearms or weapons into the Building, including but not limited to
the Premises and the Common Area, or for any damage or loss to property or
persons resulting therefrom.

8.  Tenant shall not place, install or operate in the Premises or in any part of
the Building, any engines or machinery, or maintain, use or keep any
inflammable, explosive, or hazardous material without comment of Landlord.

9.  Landlord will not be responsible for lost or stolen personal property,
equipment, money, or jewelry from Tenant's area or public room regardless of
whether such loss occurs when the area is locked against entry or not.

10. No birds or animals shall be brought into or kept in or about Building.

11. Employees of Landlord shall not receive or carry messages for or to Tenant
or other person, nor contact with or render free of paid services to Tenant's
agents, employees or invitees.

12. Landlord will not permit entrance to Tenant's offices by use of pass keys
controlled by Landlord to any person at any time without written permission by
Tenant, except employees, contractors, or service personnel directly supervised
by Landlord.

13. The entries, passages, doors, elevators, elevator doors, hallways or
stairways shall not be blocked or obstructed; no rubbish, litter, trash, or
material of any nature shall be placed, emptied or thrown into these areas; and
such areas shall not be used at any time except for ingress or egress by Tenant,
Tenant's agents, employees, invitees or visitors to or from the Premises.

14. Plumbing fixtures and appliances shall be used only for purposes for which
constructed, and no sweepings, rubbish, rags or other  unsuitable material shall
be thrown or placed therein. Damage resulting to any such fixtures or appliances
from misuse by Tenant shall be repaired and replaced at Tenant's sole cost and
expense, and Landlord shall not in any case be responsible therefor.

15. Tenant shall not do, or permit anything to be done in or about the Building,
or bring or keep anything therein, that will in any way increase the rate of
fire or other insurance on the Building, or on property kept therein, or
obstruct or interfere with the rights of, or otherwise ???? or annoy, other
tenants, or do anything in conflict with the valid pertinent laws, rules or
regulations of any governmental authority.

16. The Landlord desires to maintain highest standards of environmental comfort
and conveniences for the
<PAGE>   13
courtesy. It will be appreciated if any undesirable conditions or lack of
courtesy or attention are reported directly to the management.

17. The work of the janitor or cleaning equipment shall not be hindered by
Tenant after 5:30 p.m. and such work may be done at any time when the offices
are vacant, the windows, doors and fixtures may be cleaned at any time. Tenant
shall provide adequate waste and rubbish receptacles, cabinets, book cases, map
cases necessary to prevent unreasonable hardship if Landlord is discharging its
obligations regarding cleaning service.

18. Landlord shall have the right to determine and prescribe the weight and
proper position of any unusually heavy equipment including safes, large files,
etc., that are to be placed in the Building, and only those which in the opinion
of Landlord might act with reasonable possibility to damage to the floors,
structure and/or freight elevator, may be moved into said building. Any damage
occurred in connection with the moving or installing of such aforementioned
articles to said building of the existence of same in said building shall be
paid for by Tenant, unless otherwise covered by insurance.

19. Landlord shall have the right to prohibit the use of the name of the
Building or any other publicity by Tenant, which, in Landlord's opinion, stands
to impair the reputation of the Building or its desirability for the executive
offices of Landlord or of other lessee, and, upon written consent from Landlord.
Tenant will refrain from or discontinue such publicity.

20. The Premises shall not be used for lodging, sleeping, or cooking or for any
immoral or illegal purpose or for any purpose that will damage the premises or
the reputation thereof, or for any purpose other than that specified in the
Lease covering the Premises.


<PAGE>   14
                                   (LANDLORD)

STATE OF OKLAHOMA   )
                    ) ss.
COUNTY OF TULSA     )


     Before me, the undersigned Notary Public in and for said County and State,
on this __________ day of __________________, 19___, personally appeared Paul D.
Wilson, who subscribed the name of Twenty First Properties, Inc., an Oklahoma
corporation domesticated in Oklahoma, to the foregoing Lease Agreement as its
President and acknowledged to me that he executes the same as himself free and
voluntary act and deed and as the free and voluntary act and deed of Twenty
First Properties, Inc., an Oklahoma corporation domesticated in Oklahoma, for
the uses and purposes therein and forth.

     Witness my hand and official seal the day and year last above written.


My Commission Expires:______________________      ______________________________
                                                           Notary Public

                          (IF TENANT IS A CORPORATION)

STATE OF OKLAHOMA   )
                    ) ss.
COUNTY OF TULSA     )


     Before me, the undersigned, a Notary Public, in and for said County and
State, on this ____________ day of ________________________, 19___, personally
appeared ___________________________________, to me known to be the identical
person who subscribed the name of ____________________________________________,
a corporation, as Tenant to the foregoing Lease Agreement as its _____________,
and acknowledged to me that ________________ executed the same as _____________
free and voluntary act and deed, and as the free and voluntary act and deed of
such corporation, for the uses and purposes therein set forth.

     Witness my hand and official seal the day and year last above written.


My Commission Expires:                                     see attached
                      -----------------           ------------------------------
                                                           Notary Public

<PAGE>   15
STATE OF CALIFORNIA      )
                         ) ss.
COUNTY OF SAN DIEGO      )


On the 20th day of June, 1999, before me, the undersigned, a Notary Public in
and for said County and State, personally appeared CHARLIE SMITH known to me
___ (or proved to me on the basis of satisfactory evidence) to be the person(s)
whose name is/are subscribed to the within instrument, and acknowledged to me
that he/she/they executed the same in his/her/their authorized capacity(ies),
and that by his/her/their signature(s) on the instrument the person(s), or the
entity upon behalf of which the person(s) acted, executed the instrument.

WITNESS my hand and official seal.

/s/ MIRANDA C. LANKS
------------------------------                              [SEAL]
NOTARY PUBLIC